AWS and TPWS Application Requirements … · 1.4.1 This document sets out a series of requirements...

Rail Industry StandardRIS-0775-CCSIssue: TwoDate: December 2018

AWS and TPWSApplication Requirements

Synopsis

This document sets out requirementsand guidance for the application of theUnited Kingdom (UK) Class B trainprotection system ‘TPWS’, whichcomprises the Automatic WarningSystem (AWS) and the Train Protectionand Warning System (TPWS).

Copyright in the Railway Group documents is owned by RailSafety and Standards Board Limited. All rights are herebyreserved. No Railway Group document (in whole or in part)may be reproduced, stored in a retrieval system, ortransmitted, in any form or means, without the prior writtenpermission of Rail Safety and Standards Board Limited, or asexpressly permitted by law.

RSSB members are granted copyright licence in accordancewith the Constitution Agreement relating to Rail Safety andStandards Board Limited.

In circumstances where Rail Safety and Standards BoardLimited has granted a particular person or organisationpermission to copy extracts from Railway Group documents,Rail Safety and Standards Board Limited accepts noresponsibility for, nor any liability in connection with, the useof such extracts, or any claims arising therefrom. Thisdisclaimer applies to all forms of media in which extractsfrom Railway Group documents may be reproduced.

Published by RSSB

Uncontrolled when printed Supersedes RIS-0775-CCS Iss 1 with effect from 01/12/2018

Issue Record

Issue Date Comments

One 03/03/2018 New document containing material fromGERT8075 issue two and GEGN8675 issue two notwithin scope of Railway Group Standards.

Two 01/12/2018 Revised Part 5 and Appendices A, B and Cincorporating requirements for VDUimplementation of DMI and integration withETCS.

Revised Part 5 also replaces former Appendix Dwhich is now not used.

AWS/TPWS output requirements formerly in Part 5moved to section 4.3.

Revisions have been marked by a vertical black line in this issue. Definitions andReferences may also have been updated but these are not marked by a vertical blackline.

Superseded Documents

The following Railway Group documents are superseded, either in whole or in part asindicated:

Superseded documents Sections superseded Date whensections aresuperseded

RIS-0775-CCS issue one AWSand TPWS ApplicationRequirements

All 01/12/2018

Supply

The authoritative version of this document is available at www.rssb.co.uk/railway-group-standards. Enquiries on this document can be submitted through the RSSBCustomer Self-Service Portal https://customer-portal.rssb.co.uk/

AWS and TPWS ApplicationRequirements

of 133 RSSB

Contents

Section Description Page

Part 1 Purpose and Introduction 71.1 Purpose 71.2 Application of this document 71.3 Health and safety responsibilities 81.4 Structure of this document 81.5 Approval and authorisation of this document 8

Part 2 System Description 92.1 General introduction to AWS and TPWS 92.2 AWS 102.3 TPWS 11

Part 3 Trackside Subsystem Requirements 133.1 Requirements for trackside AWS equipment 133.2 Requirements for trackside TPWS equipment 29

Part 4 Trainborne Subsystem Requirements 394.1 Requirements for trainborne AWS equipment 394.2 Requirements for trainborne TPWS equipment 414.3 Output requirements 44

Part 5 AWS/TPWS Driver Machine Interface (DMI) 465.1 Introduction to the AWS/TPWS DMI 465.2 Integrating the AWS/TPWS DMI into a rail vehicle 475.3 AWS/TPWS DMI controls 495.4 AWS/TPWS DMI indications 645.5 AWS/TPWS DMI control functions 765.6 AWS/TPWS indication functions 805.7 AWS/TPWS onboard subsystem power-up test functions 885.8 AWS/TPWS fault indications 90

Part 6 System Availability and Integrity 936.1 Availability and integrity of the AWS/TPWS system 93

Appendices 94Appendix A AWS/TPWS DMI System Models 94

RSSB Page 3 of 133

Appendix B AWS/TPWS Control and Indication Panel 97Appendix C AWS/TPWS DMI VDU layouts 98Appendix D Not used 100Appendix E Guidance on AWS Design Principles 101Appendix F Guidance on AWS Receiver Sensitivity Testing 102Appendix G Not usedAppendix H Description of AWS and TPWS Trainborne Equipment 104Appendix I Not usedAppendix J AWS and TPWS Trainborne Equipment - Fault and Failure

Management 110Appendix K AWS Testing using a Hand-Held Permanent Magnet 125Appendix L Guidance on AWS Route Compatibility Assessments 128

Definitions 129

References 132

of 133 RSSB

List of Figures

Figure 1: TPWS typical layout 11

Figure 2: Example designs of AWS caution acknowledgement control 53

Figure 3: Example of the AWS warning acknowledged indication ('sunflower') 71

Figure 4: AWS/TPWS brake demand indication combination and transitions 84

Figure 5: AWS/TPWS DMI structural viewpoint 94

Figure 6: Train driver operational context viewpoint: AWS DMI use cases 95

Figure 7: Train driver operational context viewpoint: TPWS DMI use cases 96

Figure 8: AWS/TPWS panel layout 97

Figure 9: AWS/TPWS panel dimensions 97

Figure 10: Example layout for touch screen VDU 98

Figure 11: Example layout for soft key VDU 98

Figure 12: Typical AWS/TPWS trainborne sub-system 105

Figure 13: AWS/TPWS right side failure investigation process 111

Figure 14: AWS wrong side failure investigation process 113

Figure 15: Combined AWS/TPWS fault finding guide 117

Figure 16: Combined AWS/TPWS system fault-finding flowchart 118

RSSB Page 5 of 133

List of Tables

Table 1: Provision of AWS at signals 14

Table 2: Track transmitter frequencies for overspeed protection functionality 37

Table 3: Track transmitter frequencies for train stop functionality 37

Table 4: AWS caution acknowledgement control 51

Table 5: AWS brake demand acknowledgement control 53

Table 6: SPAD brake demand acknowledgement control 54

Table 7: Overspeed brake demand control 56

Table 8: Brake release control 57

Table 9: Train stop override control 59

Table 10: TPWS temporary isolation control 61

Table 11: AWS isolation control 62

Table 12: AWS/TPWS isolation control 63

Table 13: AWS/TPWS DMI indications 64

Table 14: AWS and TPWS audible indications 66

Table 15: AWS warning acknowledged indication ('sunflower') 68

Table 16: Brake demand and acknowledgement indications 71

Table 17: Train stop override indication 73

Table 18: TPWS temporary isolation/fault indication 75

Table 19: Common AWS/TPWS faults 119

Table 20: Test after a 'right side failure’ reported 125

Table 21: Test after a 'wrong side failure’ reported 127

of 133 RSSB

Part 1 Purpose and Introduction

1.1 Purpose

1.1.1 This document is the industry agreed and endorsed standard on the application ofthe Automatic Warning System (AWS) and the Train Protection and Warning System(TPWS) on the Great Britain (GB) mainline railway network and on trains operating onthat network. It is complementary to GERT8075, which sets out requirements fortechnical compatibility of the AWS and TPWS trackside subsystems with the AWS /TPWS onboard subsystems.

1.1.2 Conformity with the requirements in this document can be used by infrastructuremanagers (IMs) and railway undertakings (RUs) in discharging their obligations underthe Railway Safety Regulations 1999 (RSR 99).

1.1.3 Document ERA/TD/2011-11 List of Class B Systems, published by the European UnionAgency for Railways (EUAR), records that ‘TPWS’ is a UK Class B system applicable tothe whole network. In this context, ‘TPWS’ includes AWS.

1.1.4 The Control Command and Signalling Technical Specification for Interoperability(CCS TSI) section 3.1 states that ‘The requirements for Class B systems are theresponsibility of the relevant Member State’. This Rail Industry Standard, togetherwith Railway Group Standard GERT8075, fulfils that responsibility by setting out theGB industry agreed requirements for ‘TPWS’ on the GB mainline railway.

1.1.5 This document includes the TPWS Driver-Machine Interface (DMI) requirements,which have been developed to control the risk of a driver incorrectly resetting theTPWS and restarting the train after a train protection system intervention. This issometimes referred to as ‘TPWS reset and go risk’. These requirements support thedesign of a TPWS DMI which will provide operational functionality consistent with therequirements set out in the Rule Book GERT8000 and the supporting handbookRS522 that all GB mainline train operators have collectively agreed to mandate onthemselves.

1.1.6 The requirements in RIS-0775-CCS are available to both suppliers and train operatorsas widely accepted codes of practice which can be used as a means of applying theCSM RA risk acceptance principles to the hazards of a train passing the end of asignalled movement authority and a train exceeding the permissible speed, in orderto control collision risk and derailment risk. They also provide suppliers of rail vehiclesand onboard CCS subsystems with a specification of a system which is capable ofsafe integration into the GB mainline railway.

1.2 Application of this document

1.2.1 Compliance requirements and dates have not been specified because these are thesubject of internal procedures or contract conditions.

1.2.2 If you plan to do something that does not comply with a requirement in this RIS, youcan ask a Standards Committee to comment on your proposed alternative. If youwant a Standards Committee to do this, please submit your deviation applicationform to RSSB. You can find further advice in the ‘Guidance to applicants and

RSSB Page 7 of 133

members of Standards Committee on using alternative requirements’, available fromRSSB’s website www.rssb.co.uk.

1.3 Health and safety responsibilities

1.3.1 Users of documents published by RSSB are reminded of the need to consider theirown responsibilities to ensure health and safety at work and their own duties underhealth and safety legislation. RSSB does not warrant that compliance with all or anydocuments published by RSSB is sufficient in itself to ensure safe systems of work oroperation or to satisfy such responsibilities or duties.

1.4 Structure of this document

1.4.1 This document sets out a series of requirements that are sequentially numbered. Thisdocument also sets out the rationale for the requirement, explaining why therequirement is needed and its purpose and, where relevant, guidance to support therequirement. The rationale and the guidance are prefixed by the letter ‘G’.

1.4.2 Some subjects do not have specific requirements but the subject is addressed throughguidance only and, where this is the case, it is distinguished under a heading of‘Guidance’ and is prefixed by the letter ‘G’.

1.5 Approval and authorisation of this document

1.5.1 The content of this document was approved by Control Command and SignallingStandards Committee on 30 August 2018.

1.5.2 This document was authorised by RSSB on 23 October 2018.

of 133 RSSB

Part 2 System Description

2.1 General introduction to AWS and TPWS

Guidance

G 2.1.1 GERT8075 and RIS-0775-CCS cover interface and application requirements for theAWS and the TPWS. Other methods of train protection are in use on some sections ofNetwork Rail routes, including mechanical train stops, non-mechanical (magnetic)train stops and Automatic Train Protection (ATP) systems (which include trial systemsintroduced by BR on the Great Western and Chiltern lines and the European TrainControl System (ETCS)). These systems are not covered in this document.

G 2.1.2 AWS and TPWS supplement the indications given by lineside signalling systems.While lineside signals and signs give drivers the information they need on MA andpermissible speed, AWS and TPWS are provided to mitigate risk from overrun oroverspeed due to any failure to observe or obey lineside signals or signs.

G 2.1.3 AWS is provided to give train drivers in-cab warnings on the approach to signals,reductions in permissible speed, temporary / emergency speed restrictions and otherlocations where the attention of the driver needs to be attracted, such as levelcrossings. AWS applies the brakes in the event that a driver does not acknowledge thecautionary warnings given by the system.

G 2.1.4 Although the Great Western Railway introduced a form of Automatic Train Control(ATC) from 1906, AWS was developed from the Hudd system installed by the LondonMidland and Scottish Railway on the London, Tilbury & Southend line (where fog wasa problem) in 1937. AWS track equipment was gradually installed on most routes overa period from the late 1950s through to the 1980s, and AWS trainborne equipmenthas been provided on most trains operating on the network since the 1960s.

G 2.1.5 Following the Southall accident in 1997, the government decided that a moreeffective train protection system was required. However, it was considered thatprovision of a full ATP system could not be justified, partly due to the forthcomingdevelopment of the European Train Control System (ETCS), and TPWS was developedas a cost-effective alternative. Following the Ladbroke Grove accident in October1999 the completion date was brought forward by one year to December 2002.

G 2.1.6 TPWS is designed to intervene and apply the train brakes if the train passes a signaldisplaying a stop aspect or approaches a stop aspect or a speed restriction at too higha speed. Unlike AWS, TPWS does not provide any warnings to the driver, but activatesonly when it is necessary to make a brake application. Generally, the driver willpreviously have received a warning from the AWS for the same hazard.

G 2.1.7 The original intention was that the name ‘TPWS’ would cover the combination ofadditional Train Protection (TP) functionality with the existing warning functionsgiven by AWS. Thus ‘TPWS’ should be applied to the whole system, including AWS.This is how the terms were used in Annex B of the CCS TSI, where the combinedsystem is named ‘TPWS’ and it is stated that this ‘includes the functionality of AWS’.

G 2.1.8 However, in common usage the term ‘TPWS’ has come to be applied solely to thetrain protection element of the combined system, with the warning functions stillreferred to as a separate system called ‘AWS’. Due to the established use of these

RSSB Page 9 of 133

terms, including in the Rule Book, this usage is retained in GERT8075 and RIS-0775-CCS, though in certain areas such as the Driver-Machine Interface (DMI) and self-testing procedures, requirements for the two parts of the system are closely linked.

2.2 AWS

Guidance

G 2.2.1 This section provides an overview of how the AWS system operates.

G 2.2.2 So far as its application to signals is concerned, the basic AWS system operates asfollows:

a) As a train approaches a signal, it passes over AWS track equipment (one or moremagnets) which is fixed between the running rails. This comprises a permanentmagnet producing a south pole, which may be followed (in the direction of travel)by an electromagnet which produces a north pole when it is energised.

b) The magnets are sensed by a receiver mounted under the leading end of the train,and the information derived is passed to a logic unit which interfaces with theAWS equipment in the cab and with the train brake system. The equipment in thecab comprises audible and visual indicators, an ‘acknowledgement’ push button,and a switch or similar device for isolating the AWS equipment if it is defective.

c) If the signal is displaying a clear aspect, the electromagnet is energised and thetrain therefore detects a south pole followed by a north pole. This causes a bell (oran electronic equivalent) to sound in the driver’s cab, and the visual indicatordisplays an ‘all black’ state (that is, the appearance is a black circle – described inthe Rule Book as the ‘normal’ indication). No action in respect of the AWS isrequired of the driver.

d) If the signal is displaying a cautionary or stop aspect, the electromagnet is notenergised and the train therefore detects only the south pole of the permanentmagnet. This causes a horn (or an electronic equivalent) to sound in the driver’scab and the display shows ‘all black’. The driver has to acknowledge the warningby operating the ‘acknowledgement’ push button.

e) When the driver operates the push button, the horn is silenced and the visualindicator changes to a segmented black and yellow circular display (described inthe Rule Book as the ‘warning’ indication), as a reminder to the driver that he /she has acknowledged the cautionary or stop aspect being displayed by the signal.

f) If the driver fails to acknowledge the warning horn within a set time period, thebrakes are applied automatically. The visual indicator remains ‘all black’ and thehorn continues to sound.

g) If the driver acknowledges the warning after the brakes have been applied, thehorn is silenced and the indicator changes to the black and yellow display, but thetrain brakes are not released until a minimum time period has elapsed and thedriver has operated a separate brake release device.

G 2.2.3 Facilities are provided within the cab for isolating the on-board AWS equipment aloneand for full isolation of AWS and TPWS together. This is necessary in order to copewith equipment failure while the train is in service (failures could result in the trainbeing immobilised, or the horn / bell sounding continuously in the cab, for instance),

of 133 RSSB

and to deal with a train brought to a stand with its AWS receiver directly over AWStrack equipment.

G 2.2.4 Track-mounted test magnets may be provided at certain locations, for example onthe exit lines from maintenance depots, to give assurance before a train entersservice that the trainborne AWS equipment is capable of functioning correctly.

G 2.2.5 Where AWS track equipment is provided on the approach to a reduction inpermissible speed, a temporary / emergency speed restriction or a signal that cannotdisplay a clear (green) aspect, only a permanent magnet is provided and the cabequipment always operates as on the approach to a signal displaying a caution orstop aspect. The driver receives a warning (as set out in d)), and has to respond to itaccordingly, otherwise the brakes are applied automatically as set out in f) and g).

G 2.2.6 Where AWS track equipment is passed over by trains travelling in both directions, butis only applicable to movements in one direction, a suppressor magnet may beprovided. This incorporates a suppressor coil which can be energised to counteract themagnetic flux from the permanent magnet, so that the receiver on the train will notdetect the presence of the AWS track equipment.

2.3 TPWS

Guidance

G 2.3.1 TPWS (see Figure 1 for typical layout) is designed to initiate a brake applicationindependently of AWS:

a) At selected signals, if a train passes a stop aspect.b) On the approach to selected signals, if a train approaches a stop aspect at

excessive speed.c) At other locations (for example, on the approach to a permanent speed restriction

or buffer stop) if a train approaches the location at excessive speed.

Figure 1: TPWS typical layout

G 2.3.2 The TPWS track sub-system comprises pairs of transmitter loops forming either atrain stop system (TSS) or an overspeed system (OSS). These have sometimes been

RSSB Page 11 of 133

referred to as train stop sensor and overspeed sensor, but these terms are not reallyaccurate because it is the trainborne equipment which detects the frequenciestransmitted by the track sub-system loops.

G 2.3.3 A TSS consists of two loops mounted adjacent to each other in the four foot on thetrack centre line, such that the magnetic fields transmitted by the two loops overlapand are detected together by the trainborne receiver.

G 2.3.4 A TSS brake application is made if, firstly, a valid arming frequency is detected andthen, while still detecting the arming frequency, the appropriate trigger frequency isdetected, irrespective of train speed.

G 2.3.5 The OSS operates on the principle of measuring the time taken for a train to pass twopoints on the track. If this time is less than a pre-set time an automatic brakeapplication is initiated. On the track, two transmitters, each emitting a differentfrequency, define the points at which the timing starts and stops. The distancebetween the two transmitters and the trigger delay timing, which is set on the train,together determine the set speed.

G 2.3.6 More than one set of OSS loops may be provided on the approach to a signal toprovide more effective control of trains over a wider range of approach speeds. Anadditional set of OSS loops further from the signal than the primary OSS is sometimesreferred to as ‘OSS+’, and an installation incorporating such an additional set of loopsmay be referred to as ‘TPWS+’.

G 2.3.7 To avoid interference problems experienced with closely spaced OSS loops, smallerloops are used on the approach to buffer stops where the required set speed is low.

G 2.3.8 In the case of TPWS loops that are associated with a signal (the TSS at the signal andOSS on the approach to the signal), the two transmitters are energised when thesignal is required to display a stop aspect.

G 2.3.9 When associated with any other location, such as the approach to a speed restrictionor buffer stop, only an OSS is provided. The two transmitters are either permanentlyenergised or energised to coincide with the passing of a train on the line concerned.

G 2.3.10 There are two sets of frequencies that can be used for transmitter loops. Eachfrequency set contains three separate frequencies; one is for use as the OSS armingfrequency, one for the TSS arming frequency, and one for use as the trigger frequencyfor both OSS and TSS.

G 2.3.11 Either frequency set can be used for either direction of operation, and there is nospecific allocation of different frequency sets for up and down directions.

G 2.3.12 Any pair of transmitters which constitute either a TSS or an OSS only initiate anautomatic brake application if the train receives both the correct frequencies in thecorrect order. This allows trains to operate in both directions along the same line andavoids unwanted interventions when trains operate in the opposite direction alongthe same line.

G 2.3.13 It is possible to use the other pair of frequencies, at the same location, for theopposite direction of travel, and the track transmitters for the two directions may beinterleaved if necessary. Any valid pair of frequencies, detected in the correct order,should be correctly interpreted in this situation.

of 133 RSSB

Part 3 Trackside Subsystem Requirements

3.1 Requirements for trackside AWS equipment

3.1.1 Lines to be fitted

3.1.1.1 Lines to be fitted with AWS

3.1.1.1.1 AWS shall be fitted on all signalled lines, except those where an alternative trainprotection system providing a level of protection equivalent to or better than thatprovided by AWS and TPWS is fitted and operational on the infrastructure and on alltrains operating on the route.

Rationale

G 3.1.1.1.2 AWS is a warning system used to mitigate the risk from signals passed at danger(SPAD) and from overspeed, where an alternative system is not used.

Guidance

G 3.1.1.1.3 AWS (together with TPWS) is the standard system which is installed throughout thenational network, except where there is an alternative system which provides anequivalent level of protection. Such alternative systems include ATP, ETCS andmechanical trainstops.

G 3.1.1.1.4 There have been some exceptions to the fitment of AWS, which are covered byderogations. See the standards catalogue for further details of derogations whichwere made against historic issues of GERT8075 and GERT8035.

3.1.2 Equipment to be provided

3.1.2.1 Signals at which AWS is fitted

3.1.2.1.1 On fitted lines, AWS equipment shall be provided at signals in accordance with Table 1, except where AWS gaps are permitted by the provisions set out in 3.1.4.

RSSB Page 13 of 133

Type of signal at which AWS shall befitted

Exemptions from fitment

All colour light signals a) Signals that have no main signalledroute leading up to them (includingthe platform starting signal nearestto the buffer stops on bay andterminal platform lines and signalsprovided solely for turnback moves).

b) Signals that give access to runninglines from non-running lines where:

i) Trains usually come to a stand,and

ii) Trap points are provided toprotect the running line(s).

c) A colour light stop signal in a blocksignalling area where:

i) The stop signals controlled byadjacent signal boxes are notfitted with AWS trackequipment, and either

ii) This signal cannot display acautionary aspect, or

iii) If the signal displays acautionary aspect when thesignal ahead is at danger, thisaspect is approach released andpreceded by a distant signaldisplaying an ON aspect.

This exemption from fitmentdoes not apply, however, wherea colour light signal controlsentry to a single line. In thesecircumstances AWS trackequipment shall be providedunless the signal is exemptunder (a) above

All semaphore distant signals and distantboards

Table 1: Provision of AWS at signals

of 133 RSSB

Rationale - fitment at colour light signals

G 3.1.2.1.2 AWS is normally provided at all colour light signals, whether or not they can display acautionary aspect.

G 3.1.2.1.3 The green aspect at a two aspect (red / green) colour light signal is identical to thatgiven by a two-aspect distant (yellow / green) signal or by a three or four aspectsignal, and it is less confusing to drivers to give the same AWS indication in all cases.

Rationale - exceptions to fitment

G 3.1.2.1.4 Platform starting signals on bay and terminal platform lines are not provided withAWS because in many cases trains will be standing close to the signal beforedeparture and would not pass over an AWS magnet if one was provided.

G 3.1.2.1.5 Signals provided for turnback moves are applicable only to moves in the oppositedirection to the normal direction of operation on the line. Such signals can beapproached by unsignalled movements, but there is no requirement to provide AWSfor unsignalled movements. If AWS were provided at turnback signals, it would needto be suppressed for normal direction movements. As the movements approachingthe signal are not signalled routes, there is no practicable way to control the removalof suppression for these movements.

G 3.1.2.1.6 At the exit from a non-running line (such as a siding) onto a running line, there mayoften be trap points to prevent trains entering the main line when the route is not set.The trap points provide alternative protection for the main line, and fitment of AWSapproaching the exit signal is not necessary.

G 3.1.2.1.7 Where a ‘semaphore equivalent’ aspect sequence applies on a non-track circuit blockline, a train always receives a cautionary aspect at the distant signal if it is notpossible to clear all the stop signals controlled from a signal box. AWS at the distantsignal provides the necessary warning to the driver if the train does not have a clearMA through all the associated stop signals, and in these circumstances it is notnecessary to provide AWS at the stop signals.

Rationale - fitment at semaphore signals

G 3.1.2.1.8 For semaphore signals, AWS is normally provided only at distant signals, as it isapparent that a semaphore stop signal or stop board cannot display a cautionaryaspect and the driver will not expect an AWS indication at such signals.

Guidance

G 3.1.2.1.9 No guidance.

3.1.2.2 Provision of AWS trackside equipment on bi-directional lines

3.1.2.2.1 On bi-directionally signalled lines, AWS track equipment shall be provided forsignalled train movements in both directions.

Rationale

G 3.1.2.2.2 AWS is provided for all signalled movements authorised by main signals. On a sectionof track where main signalled movements apply in both directions, AWS track

RSSB Page 15 of 133

equipment is provided to give appropriate AWS indications to drivers for movementsin each direction.

Guidance

3.1.2.3 Provision of suppressed AWS

3.1.2.3.1 Where AWS is required to be suppressed, a suppressor magnet shall be providedinstead of the permanent magnet.

Rationale

G 3.1.2.3.2 A suppressor magnet is capable of generating a magnetic field that cancels out themagnetic field of the permanent magnet and therefore inhibits the AWS warning (orany other indication) being given to the driver.

Guidance

G 3.1.2.3.3 A suppressor magnet includes a permanent south pole and a suppressor coil. Whenthe suppressor coil is energised, the magnetic field resulting from the combined effectof the permanent magnet and the suppressor coil is reduced to a level below theminimum level that can be detected by an AWS receiver.

G 3.1.2.3.4 A suppressor magnet is used in preference to an electromagnet generating a southpole only when it is needed because, in failure conditions, an electromagnetic southpole could fail to generate a magnetic field and therefore fail to provide the requiredwarning. With a suppressor magnet, if the power supply or the suppression coil fails, itdefaults to an effective permanent south pole.

3.1.3 Position of equipment

3.1.3.1 Location of AWS track equipment on approach to the associated infrastructure

3.1.3.1.1 AWS track equipment shall be positioned 180 m (+ 18 m, - 9 m) before the associatedsignal or sign, except where any of the following apply:

a) On a section of line where existing AWS track equipment at successive signals ispositioned 230 m (+ 23 m, - 11.5 m) before signals, it is permissible for new AWStrack equipment also to be positioned at this distance, provided that this does notcreate additional risk.

b) On bi-directionally signalled platform lines, it is permissible to position AWS trackequipment at distances other than those specified above where common AWStrack equipment is provided for signals applying in opposite directions, in order toachieve correct operation of the equipment for train movements.

c) Where the AWS magnet is positioned less than 180 m from the signal or sign sothat the driver is able to read the associated signal aspect or sign when theaudible warning is received.

d) On a non-passenger line on which permissive working is authorised, the AWS trackequipment may be positioned beyond, but as close as practicable to, the signal.

of 133 RSSB

e) Where infrastructure constraints prevent the installation of AWS equipment at thestandard position.

f) Where an alternative position is required to meet the constraints set out in 3.1.3.2.g) Where the AWS magnet is positioned beyond the signal in the circumstances set

out as arrangement a) in 3.1.3.5.h) Where a signal sighting committee (SSC) recommends an alternative position and

this achieves a reduction in risk.

Rationale (general)

G 3.1.3.1.2 A consistent distance between the AWS magnet and the applicable signal or signhelps drivers to reliably identify which signal or sign the warning applies to, and, in thecase of approaching a signal at danger, to judge their stopping position.

G 3.1.3.1.3 A distance of 180 m (originally specified as 200 yards) gives the driver at least 2 s toread the applicable signal or sign at speeds up to 200 km/h (125 mph).

G 3.1.3.1.4 The permitted tolerance (which is +10%, –5% of the nominal distance of 180 m)allows the position of the AWS magnet to be adjusted to meet site specificconstraints without significantly altering the relationship between the magnet andthe signal or sign as perceived by the driver.

Guidance (general)

G 3.1.3.1.5 The position of AWS magnets potentially influences signal overrun risk anddriveability. The signal overrun risk assessment process is set out in RIS-0386-CCS.Further guidance on driveability assessment is given in RIS-0713-CCS.

Rationale for a)

G 3.1.3.1.6 The permitted tolerance (which is +10%, –5% of the nominal distance of 230 m)allows the position of the AWS magnet to be adjusted to meet site specificconstraints without significantly altering the relationship between the magnet andthe signal or sign as perceived by the driver.

Guidance on a)

G 3.1.3.1.7 GERT8035 issue one required AWS magnets to be positioned 230 m from the signalon higher speed lines (where the permissible speed was more than 100 mph) toprovide additional time for the driver to observe the signal after receiving the AWSindication. This requirement was withdrawn because it led to other inconsistencies,for example where there were parallel fast and slow lines with a speed exceeding100 mph on the fast line and 100 mph or less on the slow line, requiring the magnetsto be positioned at different distances from parallel signals.

G 3.1.3.1.8 In terms of equipment response, the increased distance was not necessary providedthe caution acknowledgement delay period was limited to 2 s, as a distance of 180 mallows sufficient time for the initial delay period and the caution acknowledgementdelay period to elapse before the train passes the signal at a speed of 125 mph.

G 3.1.3.1.9 Where a series of AWS magnets are installed at a distance of 230 m from consecutivesignals, it might be preferable to maintain this distance, for consistency, within the

RSSB Page 17 of 133

localised area when additions or modifications are made to the existing signallingarrangements.

Rationale for b)

G3.1.3.1.10

The use of a single set of magnets, for both directions of traffic, applying to thesignals at either end of the platform, is a practicable method of providing correctoperation of AWS for all trains without needing complex suppression controls,particularly in platforms when permissive working and joining and splitting of trainstakes place.

G3.1.3.1.11

Most platforms are less than 360 m in length, so a bi-directional arrangement with ashared magnet will require the AWS track equipment to be less than 180 m from oneor both of the signals.

Guidance on b)

G3.1.3.1.12

The minimum distance from the AWS magnet to the signal is limited by the specifiedminimum running time of 3 s set out in GERT8075. This equates to 40 m at 30 mphor 80 m at 60 mph.

G3.1.3.1.13

Where speeds in both directions are low, and most trains stop in the station, it willoften be appropriate to position the AWS magnets in the middle of the platform, thesame distance from both signals.

G3.1.3.1.14

It may be appropriate to position the AWS magnets at a greater distance from thesignal applying to normal direction movements (at or nearer to the standard distanceof 180 m) and at a reduced distance from the opposite direction signal where:

a) There is a designated normal direction of operation on the line through theplatform,

b) Speeds in the normal direction are high or a significant number of trains runthrough the station without stopping.

c) The speed for movements in the opposite direction is lower and most trains usingthe platform line in that direction will stop at the station.

Rationale for c)

G3.1.3.1.15

It is desirable to position AWS magnets so that the driver can see and interpret theapplicable signal aspect or sign at the time that the AWS warning is received.

Guidance on c)

G3.1.3.1.16

In cases where the visibility of the signal or sign is restricted, there are twoapproaches to positioning the AWS track equipment:

a) Position the AWS magnet at the standard distance (180 m) from the signal,accepting that the signal will not be visible to the driver when the warning isreceived, or

b) Position the magnet closer to the signal (subject to the minimum of 3 s runningtime set out in GERT8075), so that the signal is visible when the warning isreceived.

of 133 RSSB

G3.1.3.1.17

The preferred arrangement is for the associated signal or sign to be visible to thedriver when the AWS audible indication is received, so that the AWS indication can bereadily associated with the appropriate item of lineside equipment which the driver isrequired to observe.

Rationale for d)

G3.1.3.1.18

Positioning the AWS beyond the exit signal on a permissively worked freight lineavoids the possibility that the driver of a train which has entered an occupied sectionunder a permissive movement authority will receive a clear AWS indication when theexit signal is displaying a green aspect for a preceding train which is between theAWS magnet and the signal.

Guidance on d)

G3.1.3.1.19

If positioning the AWS beyond the exit signal is not adopted, complex controls maybe required to prevent the AWS giving a clear indication in these circumstances.

Rationale for e)

G3.1.3.1.20

At some locations, features of the infrastructure, such as bridge decks, pointwork orother obstructions, may make it impossible to install AWS track equipment at thepreferred position. In such cases an alternative position is used.

Rationale for f)

G3.1.3.1.21

3.1.3.2 identifies a number of situations which might prevent AWS track equipmentfrom being placed in the preferred position.

Guidance on e) and f)

G3.1.3.1.22

If the AWS track equipment cannot be placed at its preferred location, generally 180m (+ 18 m, – 9 m) from the signal, due to one of these constraints, and it is notpossible to relocate the item of equipment which gives rise to this constraint, the AWSequipment is moved to an alternative position.

G3.1.3.1.23

It is generally better to place the signal in its optimum position and locate the AWSequipment at a non-standard distance from the signal, rather than moving the signalto a less advantageous position so that the AWS can be placed at the standarddistance from it.

Rationale for g)

G3.1.3.1.24

Where AWS is fitted at a signal controlling train movements from a through runningline not fitted with AWS track equipment to a running line that is fitted, section a)requires the AWS track equipment to be positioned beyond the signal so that it canbe suppressed for a train routed along the unfitted line, but it will be effective for atrain routed to the fitted line.

Rationale for h)

G3.1.3.1.25

A signal sighting committee may identify specific local factors which mean thatdriveability could be improved by positioning the AWS magnet at a distance otherthan the standard distance from the signal or sign.

RSSB Page 19 of 133

Guidance on h)

G3.1.3.1.26

In recommending an alternative position for the AWS magnet, the SSC shouldconsider the factors set out in RIS-0737-CCS (signal sighting assessmentrequirements).

G3.1.3.1.27

The reasons for recommending an alternative position of an AWS magnet should berecorded on the signal sighting form.

3.1.3.2 Positions where AWS track equipment is not sited

3.1.3.2.1 AWS equipment shall not be positioned:

a) Where a train is likely to come to a stand with the receiver for the active drivingposition over the AWS track equipment.

b) Within 4 s travelling time of any other AWS track equipment (calculated at thepermissible speed), except where one or other of the sets of equipment is alwayssuppressed for any movement over them.

c) Where AWS equipment could interfere with the correct operation of AutomaticPower Control (APC) equipment, or vice versa.

d) Where the correct operation of the AWS track equipment could be jeopardised bythe proximity of DC traction cables or impedance bonds. Specifically, on DCelectrified lines, AWS track equipment shall not be positioned:

i) Less than 3.5 m from cross-track traction feeder cables, traction returnbonds or impedance bonds.

ii) Less than 1.5 s travelling time (measured at the permissible speed) beforecross-track traction feeder cables, traction return bonds or impedance bonds.

Rationale for a)

G 3.1.3.2.2 If a train comes to a stand with the active AWS receiver over AWS track equipment, itmight not be possible to acknowledge the AWS warning or release the brakes exceptby isolating the trainborne equipment.

Rationale for b)

G 3.1.3.2.3 Placing two sets of AWS track equipment within 4 s travelling time of each othercould result in the response of the trainborne AWS equipment to the first set of trackequipment, including the time to reset the receiver following acknowledgement of awarning, masking its response to the second set.

Rationale for c)

G 3.1.3.2.4 APC equipment uses magnets similar to AWS magnets but positioned each side ofthe track, with receivers mounted on the side of the vehicle.

Guidance on c)

G 3.1.3.2.5 In junction areas, care should be taken in positioning AWS and APC track equipmentso that the receiver of one system does not inadvertently detect the field from themagnets provided for the other system, leading to unwanted responses.

of 133 RSSB

Rationale for d)

G 3.1.3.2.6 AWS track equipment is positioned far enough from DC electric traction supplyequipment to avoid the magnetic field of the AWS magnet being distorted orsuppressed by magnetic fields emitted by the other equipment.

G 3.1.3.2.7 AWS is positioned far enough from cross-track traction feeder cables, traction returnbonds or impedance bonds to reduce the potential for incorrect AWS indicationscaused by stray magnetic fields.

G 3.1.3.2.8 The magnetic field from DC electric traction supply equipment could generate a northpole which could be detected by the AWS receiver on the train. If AWS trackequipment is positioned less than 1.5 s running time from DC traction equipment, anorth pole from the traction equipment could be received after the train has correctlydetected a south pole from the AWS magnet and cause a false ‘clear’ AWS indicationwhen a warning should be given.

3.1.3.3 Agreement of AWS track equipment position by SSC

3.1.3.3.1 The position of the AWS track equipment shall be agreed by a SSC where either:

a) The distance of the track equipment from the signal or sign is other than 180 m (+18 m, - 9 m), or

b) The AWS audible indication is received by the driver before the signal or signbecomes visible.

Rationale

G 3.1.3.3.2 The signal sighting process is used to confirm that lineside signals and signs areadequately visible and readable. This process should take account of the contributionof the AWS to readability and the effectiveness of the warning which it provides.

Guidance

G 3.1.3.3.3 AWS track equipment is preferably positioned to meet two conditions – a standarddistance of 180 m from the associated signal or sign, and visibility of the signal orsign when the warning is received.

G 3.1.3.3.4 These conditions are intended to provide a consistent and effective warning todrivers. Where it is not possible to achieve these conditions, the effectiveness of theAWS warning to the driver could be reduced.

G 3.1.3.3.5 There are circumstances where the AWS track equipment may be positioned so thatthe audible indication is received before the signal is visible to the driver, providedthat the time interval between receiving the AWS indication and seeing the signal isnot excessive.

G 3.1.3.3.6 Further guidance on AWS within the signal sighting assessment process is set out inRIS-0737-CCS.

RSSB Page 21 of 133

3.1.3.4 Infrastructure features that cannot be positioned between signals or signs andtheir associated AWS track equipment

3.1.3.4.1 The following infrastructure features shall not be positioned between a signal or signand its associated AWS track equipment:

a) Another main signal applicable to movements in the same direction.b) A warning indicator for a reduction in permissible speed.c) A warning board for a temporary or emergency speed restriction.d) Other AWS equipment applicable to movements in the same direction.

Rationale

G 3.1.3.4.2 When a driver receives an AWS indication, there should be no potential for confusionas to which item of signalling equipment the AWS indication relates.

Guidance

G 3.1.3.4.3 In order to avoid confusion in relating an AWS indication to the equipment for whichit is intended to give a warning, the signal or sign to which the AWS indication appliesshould be clearly identifiable by the driver. Therefore, no other items of equipmentwhich could be associated with an AWS indication should be positioned between anAWS magnet and the signal or sign to which it applies.

3.1.3.5 AWS for controlling movements from a line not fitted with AWS to a fitted line

3.1.3.5.1 Where a signal controls train movements from a running line not fitted with AWStrack equipment to a running line that is fitted, one of the following arrangementsshall apply:

a) Where there is a turnout from a through running line not fitted with AWS onto anAWS fitted line, AWS track equipment shall be provided for the stop signalcontrolling the movement onto the fitted line. The track equipment shallincorporate provision for suppression, and shall be positioned beyond, but as closeas practicable to, the signal. The signals that display cautionary aspectsassociated with the stop signal shall not be fitted with AWS, or

b) Where a running line not fitted with AWS converges with an AWS fitted line, thestop signal controlling movements from the unfitted line to the fitted line and anyassociated signals displaying cautionary aspects shall be fitted with AWS trackequipment in accordance with the requirements set out in GERT8075.

Rationale

G 3.1.3.5.2 Trains running onto a line fitted with AWS should receive an AWS indication at thesignal that controls the movement onto the fitted line. Trains continuing along theunfitted line are not given an AWS indication, as it would be inconsistent to present asingle AWS indication to the driver travelling along an otherwise unfitted line.

G 3.1.3.5.3 So that the AWS magnet can be appropriately controlled where the situation in a)applies (that is, it is suppressed for a train routed along the unfitted line but active fora train routed to the fitted line), it is located beyond the signal so that the routing ofthe train is known at the time it passes over the magnet. If the magnet was located

of 133 RSSB

before the signal, and a train approached the signal when no route had been set, itwould not be possible to determine the route that the train was to take.

G 3.1.3.5.4 Where an unfitted line leads only onto an AWS fitted line as in situation b), normalAWS indications are provided at the signals approaching the convergence as it willalways be appropriate for the train to receive them.

Guidance

G 3.1.3.5.5 The situation in a) above will not arise if all lines are fitted with AWS, but there maystill be some locations where a through goods line running parallel to a passenger linehas not been fitted.

3.1.4 AWS Gap Areas

3.1.4.1 Retention of AWS gap areas during resignalling

3.1.4.1.1 When an existing signalling layout incorporating an AWS gap area (a station area notfitted with AWS track equipment) is resignalled, AWS track equipment shall beprovided, unless both of the following apply:

a) Permissible speeds in the unfitted area do not exceed 50 km/h (30 mph), andb) A risk assessment shows that absence of AWS track equipment within the gap

area does not introduce an unacceptable risk.

Rationale

G 3.1.4.1.2 Low permissible speeds reduce the level of collision risk.

G 3.1.4.1.3 Non-provision of AWS in a gap area represents a reduction in the level of trainprotection generally provided, and AWS gaps should only be retained where theabsence of this provision can be justified.

Guidance

3.1.4.2 Identification of AWS gap areas

3.1.4.2.1 The geographical limits of an AWS gap shall be clearly identifiable.

3.1.4.2.2 Lineside signs shall be provided to indicate the commencement and termination ofthe AWS gap on all running lines that provide entry to or exit from the gap area asfollows:

a) A ‘commencement of AWS gap’ lineside sign shall be provided at or beyond thelast fitted signal and before the position where the AWS track equipment for thenext signal would have been, had it been provided, and

b) A ‘termination of AWS gap’ sign shall be provided beyond the last signal notfitted with AWS and not less than 4 s travelling time at the permissible speedbefore the AWS track equipment for the first fitted signal.

RSSB Page 23 of 133

Rationale

G 3.1.4.2.3 Areas where AWS is not provided should be easily identifiable by train drivers.

G 3.1.4.2.4 Lineside signs are provided to remind the driver of the extent of the AWS gap and toavoid any confusion over where AWS indications should be received and where theyare not provided.

Guidance

G 3.1.4.2.5 The Sectional Appendix sets out information on the location of AWS gap areas.

G 3.1.4.2.6 The design of lineside signs is specified in the online catalogue of lineside signs whichis indexed in GIGN7634.

G 3.1.4.2.7 The 'commencement of AWS gap' and 'termination of AWS gap' signs are providedwhere there is a short gap in AWS fitment on a line that is otherwise fitted, and aredistinct from the signs for ‘commencement of AWS’ and ‘termination of AWS’ usedat the transition to and from areas with other types of train protection.

3.1.5 Control of AWS track equipment

3.1.5.1 Energisation of AWS electromagnets

3.1.5.1.1 The AWS electromagnet shall be energised only when the associated colour lightsignal is displaying a green aspect, or when the associated semaphore distant signalis intentionally displaying the OFF aspect.

3.1.5.1.2 In the case of a splitting distant signal, the AWS electromagnet shall be energised ifeither signal colour light head is displaying a green aspect.

Rationale

G 3.1.5.1.3 AWS gives a clear indication (bell) to the driver when the energised electromagnet(north pole) is detected by the AWS receiver. A clear indication is given only when asignal is displaying a clear aspect (colour light signal showing green or semaphoredistant OFF). Giving an AWS clear indication in combination with any other signalaspect would be misleading to the driver.

G 3.1.5.1.4 At a splitting distant signal, a clear AWS indication is given when the signal is clearedfor either route so that the AWS indication is consistent with the green aspectdisplayed by the signal.

Guidance

3.1.5.2 Control of AWS equipment positioned beyond signals

3.1.5.2.1 Where an AWS magnet is positioned beyond the signal, as set out in situation d), theAWS track equipment shall be controlled to provide an indication that is consistentwith the aspect seen by the driver at the time of passing the signal.

of 133 RSSB

Rationale

G 3.1.5.2.2 Where the AWS magnet is located beyond the signal, the AWS indication presentedto the driver corresponds to the state of the signal seen by the driver before the trainpasses the signal.

Guidance

G 3.1.5.2.3 This may be achieved by delaying the replacement of the signal to danger until afterthe train has passed over the AWS magnet, where this can be done withoutintroducing other risks.

G 3.1.5.2.4 Where it is not reasonably practicable or desirable to delay the replacement of thesignal, the control of the AWS magnet should correspond to the aspect displayed bythe signal before it was replaced to danger.

3.1.5.3 Control of AWS equipment between fitted and unfitted lines

3.1.5.3.1 Where a suppressed AWS magnet is situated beyond the signal protecting a turnoutfrom a through unfitted line, as set out in case a) in 3.1.3.5.1, the magnet shall besuppressed for movements along the unfitted line.

3.1.5.3.2 For movements through the turnout onto the fitted line, the AWS track equipmentshall be controlled to provide an indication that is consistent with the aspect seen bythe driver at the time of passing the signal controlling the movement onto the fittedline.

Rationale

G 3.1.5.3.3 For a train running along the unfitted line, the AWS magnet is suppressed so that thedriver does not receive an AWS indication, which would give an inconsistentpresentation to the driver travelling along an otherwise unfitted line.

G 3.1.5.3.4 When the train is joining a line fitted with AWS, the magnet provides an appropriateAWS indication to the driver.

Guidance

G 3.1.5.3.5 Where the AWS magnet for movements onto the fitted line is located beyond thesignal, the AWS indication presented to the driver reflects the state of the signal seenby the driver before the train passes the signal.

G 3.1.5.3.6 This may be achieved by delaying the replacement of the signal to danger until afterthe train has passed over the AWS magnet, where this can be done withoutintroducing other risks.

G 3.1.5.3.7 Where it is not reasonably practicable or desirable to delay the replacement of thesignal, the control of the AWS magnet should correspond to the aspect displayed bythe signal before it was replaced to danger.

RSSB Page 25 of 133

3.1.6 Suppression of AWS track equipment

3.1.6.1 Application of AWS suppression

3.1.6.1.1 On bi-directionally signalled lines, except where AWS track equipment is effective formovements in both directions, the magnetic field of the AWS track equipment shallbe suppressed for signalled movements in the direction to which the equipment doesnot apply, except as permitted by 3.1.6.4 and 3.1.6.5.

Rationale

G 3.1.6.1.2 On a single / bi-directional line, where an AWS indication is applicable only in onedirection of travel, suppression of the AWS magnet prevents the driver receiving aninappropriate AWS indication when the train is passing over the equipment in theopposite direction.

Guidance

G 3.1.6.1.3 GERT8075 and item b) of 3.1.3.1 describe the situation where a single set of AWSmagnets is used to provide indications for trains in both directions, and in this casesuppression is not required.

3.1.6.2 Operation of AWS suppression

3.1.6.2.1 Where suppression of an AWS magnet is required, it shall be effective from before thevehicle on which the AWS receiver for the active driving position is mounted hasreached the AWS track equipment until that vehicle has passed over the AWS trackequipment.

Rationale

G 3.1.6.2.2 The magnet needs to be suppressed at the time that the AWS receiver passes over it.

Guidance

G 3.1.6.2.3 In order to economise on power consumption of the trackside equipment, it ispermissible for suppression to be removed as soon as the vehicle on which thereceiver (for the active driving position) is mounted has passed over the AWS trackequipment, rather than waiting for the whole train to pass clear. This may beparticularly desirable for extra strength suppressor magnets because of their high-power consumption.

3.1.6.3 AWS suppression at semaphore junction signals

3.1.6.3.1 Where a semaphore junction signal has both stop and distant arms but the distantarm(s) are not applicable to all routes, the AWS equipment shall be suppressed whenthe signal is cleared for a route to which the distant arm(s) is / are not applicable.

Rationale

G 3.1.6.3.2 This prevents the driver receiving an inappropriate AWS indication.

of 133 RSSB

Guidance

G 3.1.6.3.3 This situation will arise when a semaphore junction signal has distant arms for someof the routes from the signal but not for all of them. A driver does not receive an AWSindication when the signal is cleared for a route that is not associated with a distantsignal arm.

G 3.1.6.3.4 If no route from the signal has been cleared when a train passes over the AWSmagnet, the magnet is not suppressed and the driver of a train approaching thesignal at danger receives an AWS warning indication.

3.1.6.4 Exceptions from AWS suppression - impractical locations

3.1.6.4.1 It is permissible for AWS track equipment not to be suppressed for:

a) Shunting movements on unidirectionally signalled lines.b) Unsignalled movements.c) Movements over AWS magnets associated with warning boards for temporary /

emergency speed restrictions that are not applicable to the direction ofmovement.

Rationale

G 3.1.6.4.2 It is not generally practicable to provide suppression for movements over the AWSequipment in the opposite direction in these cases. In these circumstances drivers willexpect to receive AWS warnings that may not be applicable to the movement beingmade.

Guidance

3.1.6.5 Exceptions from AWS suppression - lightly used lines

3.1.6.5.1 On lightly used single lines it is permissible for AWS track equipment not to besuppressed for movements in the direction to which the AWS indication does notapply where this is justified by a risk assessment.

Rationale

G 3.1.6.5.2 At some locations on single lines it might not be cost effective to provide appropriatecontrols to suppress AWS magnets.

Guidance

G 3.1.6.5.3 On track circuit block lines, it is normally practicable to provide and controlsuppression for AWS associated with signals at passing loops. In this case, non-provision of suppression is limited to intermediate locations within a signallingsection, such as permissible speed warning indicators where provision and control ofsuppression may not be practicable.

G 3.1.6.5.4 On lines worked by other block and token systems, it might not be practicable toprovide and control suppression for AWS associated with signals.

RSSB Page 27 of 133

G 3.1.6.5.5 Factors to be taken into account in the risk assessment include:

a) Whether indications from unsuppressed AWS equipment could cause confusion todrivers in the vicinity of signals or signs that are applicable to the direction ofmovement.

b) The level of overrun risk at a stop signal, particularly at a signal controlling theentrance to a section of single line where the driver might subconsciously ignore avalid AWS warning as a consequence of repetitively cancelling previousunsuppressed AWS warnings.

c) The regular use of the line for special purposes such as driver training, wherereceipt of inapplicable indications from unsuppressed AWS equipment could havea particular impact on driver behaviour.

G 3.1.6.5.6 For the purposes of this risk assessment, it has been the practice to consider a linewhich has no more than two train movements per hour as a ‘lightly used line’.

3.1.6.6 Consistency of the provision of AWS suppression

3.1.6.6.1 Provision or non-provision of suppression of AWS track equipment shall be appliedconsistently on all single line sections on an operating route.

Rationale

G 3.1.6.6.2 Consistency in the application of AWS suppression helps drivers to identify thelocations where they expect to receive inapplicable warnings, and thus reduces therisk that they will ignore applicable warnings.

Guidance

G 3.1.6.6.3 Receiving inapplicable warnings from unsuppressed AWS equipment could create arisk that drivers become accustomed to ignoring AWS warnings and could also ignorewarnings that do apply to them.

G 3.1.6.6.4 Assessment of this risk forms part of the overall layout assessment process set out inRIS-0386-CCS.

3.1.7 AWS cancelling indicators

3.1.7.1 Provision of AWS cancelling indicators

3.1.7.1.1 Where AWS track equipment is not suppressed for signalled movements in theopposite direction, as permitted by 3.1.6.4 and 3.1.6.5, an AWS cancelling indicatorshall be provided for each set of track equipment.

Rationale

G 3.1.7.1.2 The AWS cancelling indicator is provided to remind the driver that the AWS warningwhich has been received is not applicable. Providing a sign to confirm that an AWSwarning does not apply reduces the likelihood that a driver will mistakenly ignore anAWS warning that does apply thinking that it is not applicable.

of 133 RSSB

Guidance

G 3.1.7.1.3 Where trains pass over unsuppressed AWS magnets provided for trains travelling inthe opposite direction, the driver receives an AWS warning which does not apply tothat train. AWS cancelling indicators indicate to the driver that the AWS warningwhich has been received is not applicable to that train and may be cancelled(acknowledged with no need to take further action).

G 3.1.7.1.4 The form of AWS cancelling indicators is specified in the online catalogue of linesidesigns, which is indexed in GIGN7634.

G 3.1.7.1.5 Requirements for the provision of cancelling indicators for temporary and emergencyspeed restriction AWS equipment are set out in GKRT0075.

3.1.7.2 Position of AWS cancelling indicators

3.1.7.2.1 The AWS cancelling indicator shall be positioned:

a) 180 m (+ 18 m, - 9 m) beyond the AWS track equipment in the direction ofmovement to which the equipment does not apply, and

b) Facing trains travelling in the direction to which the AWS track equipment doesnot apply.

Rationale

G 3.1.7.2.2 The cancelling indicator is visible to the driver when the AWS warning is received, sothat the driver can clearly identify that the AWS warning is not applicable.

Guidance

G 3.1.7.2.3 The AWS cancelling indicator is positioned so that it is readable from the normaldriving position when the train passes over the unsuppressed track equipment. Thesignal sighting assessment set out in RIS-0737-CCS is relevant to the position of alllineside signalling assets.

3.2 Requirements for trackside TPWS equipment

3.2.1 Provision of TPWS track equipment

3.2.1.1 Lines on which TPWS is provided

3.2.1.1.1 TPWS track sub-system equipment shall be provided on all passenger lines at thelocations specified in 3.2.1.2, except where exemptions are permitted by 3.2.2.1 or 3.2.2.2.

Rationale

G 3.2.1.1.2 TPWS is the default system provided to control the residual risk from SPAD andoverspeeding that is not addressed by provision of AWS.

RSSB Page 29 of 133

Guidance

G 3.2.1.1.3 TPWS (together with AWS) is the standard train protection system which is installedthroughout the national network, except where there is an alternative system whichprovides an equivalent level of protection.

3.2.1.2 Locations at which TPWS is provided

3.2.1.2.1 TPWS shall be provided at the following locations:

a) On passenger lines at all main stop signals and stop boards that protect crossingor converging movements with any running line or siding.

b) At any main stop signal on a non-passenger line that protects a crossing of, orconvergence with, a passenger line.

c) At a stop signal where conflicting movements could take place in the overlap ofthe next stop signal ahead.

d) On non-track circuit block lines with a semaphore equivalent aspect sequence, atthe first home signal at the end of a block section where conflicting movementscould take place within station limits ahead

e) On the approach to the buffer stop at the end of a passenger platform.f) On the approach to speed restrictions where the permitted speed on the approach

is 60 mph or more and the speed restriction reduces the speed by at least one-third, except for:

i) Temporary speed restrictions in place for three months or less, andii) Temporary speed restrictions in place for between three months and twelve

months, subject to risk assessment, as set out in 3.2.2.2.

Rationale for a)

G 3.2.1.2.2 TPWS is provided at signals protecting conflicting movements because these areidentified as locations where a SPAD presents a high risk.

Rationale for b)

G 3.2.1.2.3 A non-passenger movement that could enter a passenger line without authoritypresents a risk to authorised movements of passenger trains.

Rationale for c)

G 3.2.1.2.4 If it is not possible for TPWS at the following signal to stop a movement before itreaches a potential point of conflict beyond that signal, TPWS protection is providedat the previous signal.

Rationale for d)

G 3.2.1.2.5 On lines where a semaphore-type aspect sequence applies, a train is stopped, orbrought nearly to a stand, at the first home signal if there is any conflictingmovement preventing the signals ahead from being cleared. TPWS at the first stopsignal therefore protects any conflicting movement within station limits.

of 133 RSSB

Rationale for e)

G 3.2.1.2.6 Buffer stop collisions are an additional area of risk that TPWS has been designed tomitigate.

Rationale for f)

G 3.2.1.2.7 Derailment due to overspeed at speed restrictions was identified as an additional riskthat TPWS was designed to protect.

G 3.2.1.2.8 The criteria previously established for determining whether a speed reduction isprotected by AWS are also applied to determine the requirement for TPWSprotection.

G 3.2.1.2.9 While temporary speed restrictions are protected by AWS, there are practicaldifficulties in applying TPWS protection on a temporary basis. The Railway SafetyRegulations 1999 stated that temporary speed restrictions would not require TPWSprotection; however, these regulations define a temporary speed restriction as onethat is in place for three months or less.

Guidance on f)

G3.2.1.2.10

In practice, temporary speed restrictions are often in place for more than threemonths. The requirements for provision of TPWS at temporary speed restrictionswhich are in place for between three months and twelve months are set out in 3.2.2.2.

3.2.2 Exemptions to provision of TPWS track equipment

3.2.2.1 Locations exempt from TPWS fitment

3.2.2.1.1 The TPWS track sub-system is not required to be provided in the circumstances setout below:

a) Where an alternative train protection system providing a level of protectionequivalent to or better than AWS and TPWS is fitted and operational on theinfrastructure and on all trains operating on the route.

b) At a signal used solely for shunting purposes.c) At a stop signal that protects only a convergence of a passenger running line with

a locally operated emergency crossover.d) At a stop signal that protects a crossing or convergence with a passenger running

line, where the track layout and interlocking controls would prevent a collision atthe crossing or convergence in the event of a SPAD.

e) At a stop signal that protects only a convergence with a siding that is secured outof use in accordance with GERT8000.

f) Where a permissible speed indicator is provided to indicate a permissible speedthat has been imposed solely to reduce the dynamic loading on track systemsfrom rail traffic.

g) Where the attainable speed on entry to the commencement of a speed restrictionis less than 60 mph, or less than the excessive speed defined for the section oftrack.

RSSB Page 31 of 133

h) Where a permissible speed indicator is provided on the approach to a divergingjunction where the risk from overspeeding on the diverging route is mitigated byapproach control of the signalling.

Rationale for a)

G 3.2.2.1.2 TPWS does not need to be provided where an alternative train protection systemprovides an equivalent or higher level of protection for all trains using the route.

Rationale for b)

G 3.2.2.1.3 TPWS is not provided for shunting movements because the slow speed of themovement reduces the level of risk.

Rationale for c)

G 3.2.2.1.4 TPWS is not provided for protection of an emergency crossover which is infrequentlyused and where the local control arrangements will limit the impact of irregularoperation.

Rationale for d)

G 3.2.2.1.5 TPWS does not need to be provided where a train which passes a signal at danger willbe diverted by trap points or similar layout configurations and will not reach a pointof conflict with a train passing on the protected line.

Rationale for e)

G 3.2.2.1.6 TPWS is not provided for protection of a siding which is secured out of use and whichcan only be used infrequently under local control arrangements.

Rationale for f)

G 3.2.2.1.7 A speed restriction may be imposed to reduce the loading on the track, but where thisis the only reason for the speed restriction there is no risk from derailment due tooverspeeding.

Rationale for g)

G 3.2.2.1.8 The risk from overspeeding at a speed restriction is related to the maximumattainable speed of trains, which may be less than the permissible speed.

Rationale for h)

G 3.2.2.1.9 Approach release of a junction signal for a diverging route enforces a speed reductionon approaching trains through the signal aspects, and this provides an alternativemethod of controlling the risk from overspeeding.

Guidance

G3.2.2.1.10

No guidance.

of 133 RSSB

3.2.2.2 Locations that may be exempt from TPWS fitment

3.2.2.2.1 In the circumstances set out below, the TPWS track sub-system need be fitted onlywhere the results of a risk assessment show that the fitment of TPWS is justified inorder to reduce risk so far as reasonably practicable:

a) On the approach to a permissible speed indicator where, in order to preventunwarranted emergency brake applications on freight trains passing over theTPWS OSS, the position of the OSS would have to be adjusted such that it wouldprovide no protection to any trains.

b) On the approach to a permissible speed indicator solely associated with a plainline curve where there is a potential risk from derailment or overturning.

c) Where a permissible speed indicator is provided to indicate a permissible speedthat has been imposed solely to protect trains from the infrastructure or otherpassing trains due to limited clearance.

d) Where a permissible speed indicator is provided on the approach to a footpath orbridleway level crossing for the sole purpose of increasing the warning time forcrossing users.

e) For temporary speed restrictions that are planned to be in place for between threeand twelve months.

Rationale for a)

G 3.2.2.2.2 In some locations it is not possible to provide OSS protection for a speed restrictionthat will be effective in preventing overspeed risk for one category of train withoutthe likelihood that it will cause unwarranted interventions for other types of train.

Guidance on a)

G 3.2.2.2.3 These circumstances can arise because the different trigger delay timer settings forpassenger and freight trains, which lead to different interpretations of the set speedof an OSS loop, are optimised for the speed profiles of trains braking to a stand.Therefore they might not correctly reflect the difference in the speed profiles ofpassenger and freight trains on the approach to a speed restriction, which might alsobe influenced by a lower approach speed for freight trains or different permissiblespeeds at the speed restriction for different types of train.

Rationale for b)

G 3.2.2.2.4 At some locations on the approach to a curve, even though the reduction inpermissible speed meets the criteria requiring provision of TPWS, the potential for atrain derailing or overturning on the curve is very low.

Rationale for c)

G 3.2.2.2.5 Speed restrictions are imposed as a mitigating measure where clearances betweentrains and infrastructure or between passing trains are limited, but the risk fromactual contact is small.

RSSB Page 33 of 133

Rationale for d)

G 3.2.2.2.6 A speed restriction can be imposed to provide the required minimum warning time forcrossing users, but, while there may be a risk to individual crossing users, the overallrisk to the train from excessive speed is small.

Rationale for e)

G 3.2.2.2.7 Derailment due to overspeed at speed restrictions was identified as an additionalresidual risk that TPWS should be designed to protect, but it might not be practicableto provide TPWS at temporary speed restrictions.

Guidance on e)

G 3.2.2.2.8 Although the Railway Safety Regulations 1999 exempted temporary speedrestrictions from the requirement for TPWS protection, these regulations define atemporary speed restriction as one that is in place for three months or less.

G 3.2.2.2.9 In practice, temporary speed restrictions are often in place for more than threemonths. Any speed restriction that comes within the TPWS fitment criteria and is inplace for more than three months would therefore require TPWS to be provided. Anexemption was granted to the Railway Safety Regulations permitting TPWS not to beprovided at a temporary speed restriction in place for up to 12 months if this does notcreate excessive risk.

3.2.2.3 Permitted disconnection of trackside TPWS equipment

3.2.2.3.1 The TPWS track sub-system is not required to be operational in the circumstances setout below:

a) When the track sub-system is to be disconnected, removed, replaced orrepositioned in accordance with engineering protection or possessionarrangements, as set out in the Rule Book, and

b) When the track sub-system is to be disconnected to facilitate other work, providedthat permission to disconnect has been obtained in accordance with the RuleBook.

Rationale

G 3.2.2.3.2 The Railway Safety Regulations did not allow for disconnection or temporary removalof TPWS track equipment during possessions or other work; an exemption wasgranted to allow this.

Guidance

3.2.3 Positioning of trackside TPWS OSS equipment

3.2.3.1 Positioning of trackside TPWS OSS equipment

3.2.3.1.1 OSS transmitters shall be positioned to optimise their safety benefits, taking accountof:

of 133 RSSB

a) The braking performance of trains, as set out in GMRT2045.b) The attainable speeds of trains on the approach to the signal or other location.c) The distance from the stop signal to the point of conflict at the crossing or

convergence ahead.d) The gradient of the line on the approach to the signal or other location.e) The interleaving of other location OSS functions where signal OSS and TSS

functions are, or will be, installed.f) The potential for inhibition of the vehicle TPWS self-test on power-up.g) The potential for unwarranted intervention during movements in the opposite

direction on bi-directional or reversible lines.

Rationale

G 3.2.3.1.2 TPWS is not always able to provide fully effective protection for all trains approachingat speeds up to the maximum permissible speed of the line. Initial development ofTPWS was based on an assumed braking rate of 12%g for passenger trains, but notall trains can achieve this.

G 3.2.3.1.3 Item f) is included because a vehicle fitted with older designs of TPWS equipmentthat is powered up while standing over a TPWS transmitter may be unable tocomplete the TPWS self-test due to the presence of the frequency transmitted by theloop. Positioning of transmitters should therefore, as far as practicable, avoid placingloops where trains may stand with their receiver over the loop, shut down and start upagain (including locations where drivers may need to change cabs or where trainsmay be split).

Guidance

G 3.2.3.1.4 To improve the effectiveness over a wider range of speeds, additional loops can beprovided, but the provision of more than two OSS loops (‘standard’ and ‘TPWS+’) onthe approach to any signal is rarely justifiable.

G 3.2.3.1.5 The policy developed by the TPWS Strategy Group and approved by the RSSB Boardin 2011 is:

a) For new scheme designs, taking due account of future ERTMS fitment:

i) Network Rail to continue to apply the design principle that calculates thenumber of loops necessary to protect 12%g trains, and then optimise thedesign on a site-by-site basis to maximise the protection provided by thatnumber of loops, so that it provides better protection for lower braking ratetrains that will continue to use the routes into the future.

ii) Network Rail to use the development of the TPWS effectiveness calculatorwithin the Signal Overrun Risk Assessment Tool (SORAT) process and apply iton a signal-by-signal basis to new scheme designs to determine if it wouldbe reasonably practicable to implement an extra OSS loop based on theimprovement in the effectiveness (and hence the potential safety benefit) itdelivers.

Network Rail will demonstrate to the TOCs that they have applied these principleswhen undertaking the joint review of signalling scheme plans prior to their finalapproval.

RSSB Page 35 of 133

b) For existing signals, as part of Network Rail’s five-year review programme for eachjunction signal (prioritised based on the RSSB risk ranked list) and taking dueaccount of future ERTMS fitment:

i) Use the development of the TPWS effectiveness calculator within theSORAT process and apply it to determine if it would be reasonablypracticable to implement an extra OSS loop based on the improvement inthe effectiveness (and hence the potential safety benefit) it delivers.

3.2.3.2 Review of the position of trackside TPWS OSS equipment

3.2.3.2.1 The provision and positioning of the TPWS track sub-system shall be reviewed if achange to the infrastructure or the operational use of the railway is proposed whichmay affect the track layout, signal location, the attainable speed of trains, or thesignal passed at danger (SPAD) risk.

Rationale

G 3.2.3.2.2 Changes to any parameter can reduce the effectiveness of TPWS and may mean thatpreviously determined positioning of track transmitters is no longer optimal.

Guidance

G 3.2.3.2.3 This should also take account of changes to the characteristics of trains using the line,for example the replacement of trains which can achieve 12%g braking by trains withlower braking capability.

3.2.4 Magnetic field requirements for TPWS track equipment

3.2.4.1 Interleaving and nesting of TPWS trackside equipment

3.2.4.1.1 It is permissible to use either sequence of track transmitter frequencies to provide theappropriate function for either direction of operation.

3.2.4.1.2 It is permissible to interleave or nest TSS or OSS transmitters using one set offrequencies (set A or set B) with TSS or OSS transmitters of the other set offrequencies. TSS or OSS transmitters of the same frequency set shall not beinterleaved or nested.

Rationale

G 3.2.4.1.3 The use of alternative frequency sets and the ability to interleave and nest tracktransmitters gives the flexibility necessary to allow configurations of TPWStransmitters which provide appropriate information to control the speed of trains inthe variety of circumstances that may arise in application of TPWS to track andsignalling layouts.

Guidance

G 3.2.4.1.4 The frequency sets are set out in GERT8075 as follows:

of 133 RSSB

Frequency set Arming frequency Trigger frequency

OSS frequency set A 64.25 kHz (f1) 65.25 kHz (f2)

OSS frequency set B 64.75 kHz (f4) 65.75 kHz (f5)

Table 2: Track transmitter frequencies for overspeed protection functionality

Frequency set Arming frequency Trigger frequency

TSS frequency set A 66.25 kHz (f3) 65.25 kHz (f2)

TSS frequency set B 66.75 kHz (f6) 65.75 kHz (f5)

Table 3: Track transmitter frequencies for train stop functionality

The second set of frequencies was originally intended for use in the opposite directionon bi-directionally signalled track. However, it was realised that both sets offrequencies could be utilised in the same direction to enable multiple OSS and TSSinstallations to be more closely spaced than if restricted to a single set of frequencies.

G 3.2.4.1.5 The use of alternative frequency sets and the possibility of interleaving and nestingtrack transmitters means that TPWS receivers need to be capable of correctlyinterpreting the various permitted arrangements.

3.2.5 Control of TPWS track equipment

3.2.5.1 Control of TPWS track transmitters associated with signals

3.2.5.1.1 The track transmitters associated with signals shall be energised when the signal iscontrolled to danger.

Rationale

G 3.2.5.1.2 When a signal is at danger, all the associated TPWS loops (TSS and one or more OSS,if provided) are energised, so that the TPWS receiver on a train passing over themdetects the transmitted signals and initiates an intervention if the train passes any ofthe OSS loops at excessive speed or if it passes the signal at danger and passes overthe TSS.

Guidance

G 3.2.5.1.3 When the signal is displaying any proceed aspect (main or subsidiary), the TPWSloops are de-energised and therefore a passing train will not receive any interventionfrom the TPWS.

G 3.2.5.1.4 In some earlier installations, it was the practice to de-energise the TSS when asubsidiary aspect was cleared but keep the OSS energised. This was based on theassumption that a train approaching a cleared subsidiary aspect would not exceedthe set speed at the OSS loops. However, in some cases it was found that trains

RSSB Page 37 of 133

proceeding towards the cleared subsidiary aspect were tripped at the OSS loops,although their speed was not considered excessive. Therefore, the practice is now tode-energise all loops, including the OSS, when a subsidiary aspect is displayed. Inmany cases the approach release applied to a subsidiary aspect will not allow theaspect to clear until after the train has passed over the OSS.

G 3.2.5.1.5 The infrastructure manager (IM) has arrangements in place to identify the failure ofthe TPWS track sub-system to transmit a magnetic field when it is required, so that analternative safe system of working of trains can be implemented without unduedelay.

G 3.2.5.1.6 For TPWS fitted to signals, failures will normally be indicated to the signaller, and themeans of notification of failure should generally be immediate and automatic. Wherethis is not practicable, for example at stop boards on Radio Electronic Token Block(RETB) lines, the notification may be by means of a TPWS failure indication to thedriver.

3.2.5.2 Control of TPWS track transmitters associated with assets other than signals

3.2.5.2.1 The track transmitters provided at locations other than signals shall always beenergised when a train is passing over the transmitter on the line concerned.

Rationale

G 3.2.5.2.2 Intervention will always be required if a train exceeds the set speed at the OSS loopson the approach to an ‘other location’ (a speed restriction or buffer stops).

Guidance

G 3.2.5.2.3 The loops at other locations may be permanently energised or, to economise onpower supplies, may be energised only when a train is passing over them.

G 3.2.5.2.4 In the case of TPWS transmitters at other locations, the IM determines the mostappropriate method of failure notification.

of 133 RSSB

Part 4 Trainborne Subsystem Requirements

4.1 Requirements for trainborne AWS equipment

4.1.1 Self-test capability of trainborne AWS equipment

4.1.1.1 AWS trainborne self-test routine

4.1.1.1.1 The trainborne AWS equipment shall have a built-in self-test routine which, as aminimum, tests the following features:

a) That the audible and visual indications operate correctly when required to do so,and

b) That an AWS brake demand is requested when required.

Rationale

G 4.1.1.1.2 Because AWS is considered to be a primary safety system, the principal features ofthe trainborne system are tested for correct operation before the start of eachjourney to give assurance that the system is capable of providing effective protectionfor the train.

Guidance

G 4.1.1.1.3 The self-test requirements set out in 5.7.1 only test the functionality of the systemand the driver interface, and do not on their own confirm that the AWS receiver willactually detect track magnets.

4.1.1.2 Initiation of AWS power-up test routine

4.1.1.2.1 The AWS power-up test routine, as set out in 5.7.1, shall be initiated whenever thetrain is powered up or, in the case of dual cab trains, when the driver changes cab.

Rationale

G 4.1.1.2.2 The test is carried out when a cab is brought into use. In the case of a dual-cablocomotive, although a single AWS receiver provides input to both cabs, the audibleand visual indications are separate for each cab and are therefore tested separatelywhen the driver changes ends.

Guidance

G 4.1.1.2.3 Detailed requirements for the power-up test and the layout and functionality of theDMI are set out in Part 5.

4.1.1.3 AWS self-test following transition

4.1.1.3.1 An AWS self-test routine shall be conducted automatically when a train enters aportion of line where the trainborne AWS equipment is required to be active, havingpreviously been suppressed, unless monitoring the AWS trainborne subsystem while itis in the suppressed state provides an equivalent level of confidence in the health ofthe AWS system to that given by the self-test routine.

RSSB Page 39 of 133

4.1.1.3.2 When carrying out an AWS self-test in these circumstances, it is not necessary to testthat a brake demand is requested if this has been done when the train or cab waspowered up.

Rationale

G 4.1.1.3.3 Testing or monitoring the AWS provides assurance that the system will be capable ofproviding the necessary train protection functionality when the train transitions fromthe alternative train protection system.

Guidance

G 4.1.1.3.4 There are two methods of assuring that the AWS system will operate correctly whenthe train transitions from an alternative train protection system:

a) Causing the system to perform a self-test at the point of transition.b) Monitoring the functionality of the system when it is in a suppressed state, and

indicating to the driver a fault that means that it will not operate correctly when itis unsuppressed.

G 4.1.1.3.5 It is sometimes required to carry out the AWS self-test at the point of transition froman alternative system to AWS without stopping the train. In these circumstances itwould be impracticable to require a brake demand to be initiated as part of the self-test routine.

4.1.1.4 Successful completion of AWS self-test

4.1.1.4.1 On successful completion of the self-test routine the trainborne AWS equipment shallmove to the operational ready state.

Rationale

G 4.1.1.4.2 When the self-test has confirmed that the AWS sub-system is in a healthy state, theequipment is ready to detect and respond to magnets on the track.

Guidance

4.1.1.5 Failure to successfully complete AWS self-test

4.1.1.5.1 If the AWS self-test fails to complete successfully, the trainborne AWS equipmentshall provide notification to the driver.

Rationale

G 4.1.1.5.2 If the self-test routine fails to complete, the driver is made aware that AWS is notoperational so that the appropriate action can be taken to deal with faultyequipment.

of 133 RSSB

Guidance

G 4.1.1.5.3 When the self-test includes initiation of a brake demand, failure to complete the testusually results in the brakes remaining applied. It may then be necessary to isolatethe system to release the brakes in order to allow the train to be moved.

G 4.1.1.5.4 When the self-test does not include a brake demand, failure to complete the test doesnot usually result in a brake application, but may prevent the system switching toAWS mode. The driver is given a clear warning of the failure and may need to applythe appropriate operating rules if the train is to enter AWS-fitted lines with thesystem not fully operational.

4.2 Requirements for trainborne TPWS equipment

4.2.1 Circumstances when the TPWS trainborne subsystem is not required to beoperational

4.2.1.1 The TPWS train sub-system is not required to be operational in the circumstances setout below:

a) The TPWS train sub-system may be temporarily isolated:

i) When vehicles fitted with TPWS are working in a T3 possession.ii) When temporary block working or emergency special working is

implemented and a train is required to pass signals at danger, withauthority, in accordance with GERT8000.

iii) On driving units with an active cab that is not at the front of the train, inaccordance with GERT8000.

b) It is permissible to suppress the operation of the TPWS train sub-system when analternative train protection system is fitted and operational on both the train andthe track over which the train is to operate.

Rationale for a)

G 4.2.1.2 Vehicles operating within a possession are protected by the applicable operating ruleswhich do not depend on the observance of fixed signals; in some cases drivers mightbe required to disregard the aspects displayed by signals.

G 4.2.1.3 Temporary block working and emergency special working are forms of degradedworking introduced when parts of the signalling system have failed or areunavailable. Trains are authorised to disregard the aspects displayed by a number ofsignals and to pass them if they are at danger. In such circumstances it would beinappropriate for the train to be tripped by TPWS on passing these signals, and TPWSis therefore temporarily isolated. Alternative protection is provided by the specialoperating rules which are applied.

G 4.2.1.4 When a train has to be driven from a cab which is not at the front of the train, TPWScan be isolated to avoid unwanted interventions. Otherwise the train would be trippedby TPWS at signals which would be replaced to danger when the first vehicle passesthe signal, thus energising the TPWS TSS loops before the active TPWS receiverpasses over them.

RSSB Page 41 of 133

Rationale for b)

G 4.2.1.5 When a train is operating with an alternative train protection system, the TPWStrainborne equipment can be suppressed. This prevents unwarranted TPWSinterventions which could otherwise occur when the train is operating in accordancewith its MA under the constraints provided by the alternative system.

Guidance on b)

G 4.2.1.6 It is not necessary to suppress TPWS if either:

a) No TPWS track equipment is provided on the section of track where thealternative system is used, or

b) TPWS interventions will only occur when the train is operating outside theparameters of its MA, and any duplication of warnings or interventions that couldarise between TPWS and the other system will not create conflicting or confusingindications to the driver.

4.2.2 Trainborne TPWS power-up self-test

4.2.2.1 The TPWS shall perform a power-up test, as set out in 5.7.1, when the system isstarted, subject to awaiting initialisation of ETCS when the TPWS indications arepresented by the ETCS DMI.

Rationale

G 4.2.2.2 As TPWS is a critical safety system, its correct operation is tested before a train entersservice.

Guidance

G 4.2.2.3 The power-up test is normally started as soon as the TPWS is powered up, but wherethe TPWS indications are integrated into the ETCS DMI it may be necessary to delaythe start of the test until the DMI indications are available.

4.2.3 Trainborne TPWS equipment in-service monitoring

4.2.3.1 In-service monitoring of trainborne TPWS equipment

4.2.3.1.1 The TPWS shall undertake system monitoring while in service. System monitoringshall continue to be undertaken while the train is operating with TPWS suppressed, asset out in 4.2.1.

Rationale

G 4.2.3.1.2 As TPWS is a critical safety system and, unlike AWS, cannot be monitored by thedriver observing its regular operation during a journey, the system monitors its correctoperation while in service.

Guidance

of 133 RSSB

4.2.3.2 Indication of a trainborne TPWS fault

4.2.3.2.1 A TPWS fault that results in loss of the protection normally provided by TPWS shall beindicated as a fault, as set out in 5.8.2, but shall not apply the brakes solely due to thedetection of the fault.

Rationale

G 4.2.3.2.2 A train is taken out of service if TPWS is not operational because the protection itprovides is no longer available. A fault which requires action to be taken is indicatedto the driver.

G 4.2.3.2.3 The brakes are not applied automatically when a fault is detected, as bringing thetrain immediately to a stand in an uncontrolled manner may introduce more risk thanallowing the driver to stop the train in a controlled manner.

Guidance

G 4.2.3.2.4 RIS-3437-TOM sets out requirements for contingency plans to be applied when on-train equipment, including TPWS, becomes defective.

4.2.3.3 In-service monitoring and fault display functions of onboard TPWS

4.2.3.3.1 The in-service monitoring and fault display functions shall not disable or compromisethe train stop or overspeed functionality of the TPWS, or the functionality of theAWS. Detection of a fault shall not suppress an existing brake demand.

Rationale

G 4.2.3.3.2 Even when a fault has been detected, TPWS might still be able to intervene whenrequired, and AWS might still be operational. The ability of the system to provideprotection should be maintained where possible.

Guidance

4.2.3.4 Faults to be detected by in-service monitoring of onboard TPWS equipment

4.2.3.4.1 Faults to be detected while the train is in service shall include:

a) Electrical continuity failure between the aerial and the control unit.b) Degradation in signal transfer between the aerial and the control unit.c) A control unit fault that could result in loss of TPWS protection.

Rationale

G 4.2.3.4.2 Detectable faults that mean that the train is no longer being protected by TPWS areindicated to the driver, as these may require the train to be taken out of service.

Guidance

RSSB Page 43 of 133

4.3 Output requirements

4.3.1 Outputs from AWS/TPWS to on-train data recording

4.3.1.1 In addition to the on-train data recording requirements set out in GMRT2472, AWSand TPWS shall supply suitable and sufficient outputs to facilitate connection to theon-train data recorder, to enable the status of each of the TPWS DMI functions to berecorded.

Rationale

G 4.3.1.2 The specific cause of a brake demand (SPAD, Overspeed or AWS) is a safety-relatedfunction and is therefore required to be recorded individually. Additionally,acknowledgement, cancellation and isolation inputs are recorded in order to facilitateincident investigation.

Guidance

G 4.3.1.3 A serial data link may be necessary to accommodate the required number of outputsto the data recorder – this may raise compatibility issues with existing data recordersused with earlier versions of TPWS equipment which had parallel data outputs.

G 4.3.1.4 AWS and TPWS related activities to be recorded are likely to include the following,although the precise application is vehicle specific:

a) Train brake demand by AWS or TPWS.b) Operation of AWS and the driver’s response.c) Isolation of AWS.d) Operation of TPWS and the driver’s response.e) Isolation and override of TPWS.f) Operation of the AWS visual indicator.g) Operation by the driver of the AWS reset pushbutton.h) Sounding of the audible AWS caution indication (horn or electronic tone).i) Sounding of the audible AWS clear indication (bell or electronic chime).j) Brake demand requested by AWS or TPWS.k) Isolation of the AWS/TPWS control unit.l) Operation by the driver of the TPWS acknowledge pushbutton(s).m) Normal direction TPWS transmitter loop detected.n) Opposite direction TPWS transmitter loop detected.o) Train stop override (TSO) pushbutton operated.p) Fault and / or temporary isolation of the TPWS control unit.q) Full isolation of the TPWS control unit.

4.3.2 Outputs from the AWS/TPWS to the vigilance system

4.3.2.1 An output shall be provided from the AWS acknowledgement device to reset thedriver vigilance system when an AWS warning has been acknowledged.

of 133 RSSB

Rationale

G 4.3.2.2 This enables an AWS acknowledgement to be recognised as a relevant driver activitythat resets the vigilance system and reduces the need for the driver to make aseparate action to reset the vigilance system.

Guidance

G 4.3.2.3 No guidance.

RSSB Page 45 of 133

Part 5 AWS/TPWS Driver Machine Interface (DMI)

5.1 Introduction to the AWS/TPWS DMI

Guidance

G 5.1.1 The train driving task is a continuous process, which requires the train driver to:

a) Monitor the railway environment.b) Obtain information from indications provided at the lineside and within the cab,

from other people and use of procedures.c) Assimilate all the available information and use it to inform decisions.d) Control the train to maintain the required speed, including starting, stopping,

accelerating, and braking.

G 5.1.2 Part 5 sets out the requirements of AWS/TPWS onboard subsystems that supporttrain driving, the rationale for the requirements, and guidance on how to meet therequirements. The requirements permit a physical panel-based DMI solution or avisual display unit (VDU) based DMI solution. A VDU based solution may beintegrated with the ERTMS/ETCS DMI.

G 5.1.3 Part 5 incorporates findings from RSSB research projects:

a) T906, which conducted a task and error analysis to evaluate the benefits ofintegrating Class B CCS systems into ETCS, from the train driver perspective.

b) T1079, which proposed a VDU DMI design based on train driver feedback.

G 5.1.4 The requirements can be used to inform the design of the AWS/TPWS DMI so that itcontributes to a rail vehicle design that is capable of being safely integrated withtrain operations on the GB mainline railway. This is supported if the AWS/TPWS DMIis:

a) Operable.b) Readable.c) Audible.d) Interpretable.

G 5.1.5 These capabilities are realised if:

a) The controls enable train drivers to interact with the AWS/TPWS onboardsubsystem correctly and efficiently.

b) The indications enable train drivers to easily obtain and correctly interpretnecessary information.

G 5.1.6 A Proposer can use conformity with the DMI requirements to support a claim thathazards arising at the AWS/TPWS interface with train drivers, which contribute toSPAD risk and overspeed risk, are controlled. These hazards include:

a) Poor operability.b) Poor readability.c) Poor audibility.d) Poor interpretability.

of 133 RSSB

G 5.1.7 It is good practice to consult with the train operating company that will operate therail vehicles before finalising the design of the AWS/TPWS DMI. If the train operatoris not known, the assumptions about the operational context should be recorded sothat they can be used by the train operator to inform their decisions about safeintegration.

G 5.1.8 GERT8000 Rule Book and RS522 set out the operating rules and procedures relevantto the AWS/TPWS.

G 5.1.9 Appendix A, AWS/TPWS DMI system models includes some structural and functionalviewpoints of the AWS/TPWS DMI that illustrate the interfaces with other systems.

5.2 Integrating the AWS/TPWS DMI into a rail vehicle

5.2.1 Configuration of AWS/TPWS DMI controls and indications

5.2.1.1 The configuration of the AWS/TPWS DMI controls and indications shall be consistentfor each type or class of rail vehicle throughout an RU's fleet.

Rationale

G 5.2.1.2 Integration with train operations: Providing an AWS/TPWS DMI that has a consistentlayout, appearance and functionality supports the train driving task and reduces thelikelihood of human error. It also supports train driver learning and knowledgeretention, which assists drivers who frequently change stock type and simplifies driverstock conversion training.

Guidance on managing inconsistency

G 5.2.1.3 Inconsistency in layout, appearance or functionality within a rail vehicle fleet mightarise due to:

a) Existing rail vehicles fitted with an AWS/TPWS DMI compliant with a previousstandard.

b) Transfer of rail vehicles with a different design of AWS/TPWS DMI from anotherRU.

c) Fitment of a compliant AWS/TPWS DMI during the migration phase.

G 5.2.1.4 Any risk arising from inconsistency can be managed through train driver training andbriefing.

Guidance on provision of AWS functionality

G 5.2.1.5 Where a rail vehicle is fitted with TPWS but not AWS, the DMI incorporates only thecontrols and indications required for TPWS.

Guidance on a panel-based DMI solution

G 5.2.1.6 Appendix B, AWS/TPWS control and indication panel details the industry agreed andendorsed panel-based DMI solution which was developed following industry researchand consultation into the causes of TPWS 'reset and go' risk. This design takesaccount of the range of environments in which the panel may be located andoperated.

RSSB Page 47 of 133

Guidance on a VDU based DMI solution

G 5.2.1.7 Appendix C, AWS/TPWS DMI VDU layouts shows examples of screen layouts forimplementation of the AWS/TPWS DMI on both touch screen and soft key types ofVDU.

G 5.2.1.8 Glare can affect the readability of all VDU based controls and indications, includingthe ETCS onboard subsystem DMI.

G 5.2.1.9 Touch screen and soft key controls and indications can be activated to draw the traindriver's attention at any given moment, which can eliminate the likelihood of humanerror of operating wrong controls. Risk assessment is used to confirm thatimplementing this functionality would not encourage train drivers to operate theAWS/TPWS DMI controls without following operating procedures.

Guidance on an ETCS integrated DMI solution

G 5.2.1.10 ERTMS/ETCS DMI controls have three states: ‘enabled’, ‘disabled’ or ‘pressed’.

G 5.2.1.11 If the AWS/TPWS is integrated with the ERTMS/ETCS DMI, the DMI will only displaythe controls and indicators that are applicable to the given ETCS level.

G 5.2.1.12 In Levels NTC, NID_NTC=20 or 21, the presence of the AWS/TPWS controls andindicators on the VDU screen, in particular the AWS ‘sunflower’, reminds the traindriver that the train protection is provided by the TPWS, not the ETCS. In other levels,the absence of AWS/TPWS controls and indicators will remind the driver that the trainis protected by the ETCS.

G 5.2.1.13 These cues support the train driving task when the train transitions between Class Aand Class B systems and would not be available if the AWS/TPWS DMI is notintegrated with the ERTMS/ETCS DMI.

G 5.2.1.14 An integrated DMI will:

a) Reduce the amount of equipment fitted to the driving cab desk.b) Reduce clutter within the cab and provide the train driver with one interface. This

is likely to reduce task complexity.c) Allow all audible and visual alarms and indications to be controlled by one central

‘system’, which can avoid visual or auditory conflicts within the cab.

G 5.2.1.15 RIS-0797-CCS and RIS-0798-CCS set out further requirements for integrating AWS/TPWS with the ERTMS/ETCS onboard subsystem.

Guidance on 'dual-screen' VDU DMI solution

G 5.2.1.16 Some rail vehicle designs implement a ‘dual-screen’ VDU based DMI solution, tomeet a specified reliability and availability target. In this case, the relevant AWS/TPWS DMI controls and indications are presented on one or both of the VDU screensduring normal operations. If one of the VDU screens fails, the CCS onboardsubsystem is configured to present the AWS/TPWS controls and indications on theremaining operational VDU screen. Integration of the AWS/TPWS controls andindications into a single VDU screen might be inconsistent with the minimumdimensions set out in this RIS. Assessment of the proposed design can be used toconfirm:

of 133 RSSB

a) The visible indications are readable and interpretable in the degraded modeoperational context.

b) The VDU based controls are operable in the degraded mode operational context.

G 5.2.1.17 The degraded mode assessment takes account of the requirements for degradedmode operations set out in the RU safety management system. Any assumptions,dependencies and caveats underpinning the assessment decision are recorded in thetechnical file. The assessment record can be used by the RU to confirm that thedegraded AWS/TPWS controls and indications are fit for their intended purpose.

Guidance on further requirements

G 5.2.1.18 GMRT2161 sets out the requirements for the layout of driving cabs for rail vehiclesoperated on the GB mainline railway, including the positioning of primary controls.

G 5.2.1.19 GMRT2185 sets out further requirements for the security of the isolation controls fortrain safety systems.

G 5.2.1.20 ERA-ERTMS-015560 version 3.6.0 sets out further requirements for the ERTMS/ETCSDMI screen layout, including the ‘sub-areas’ in terms of number of cells, number ofcells in total grid array (640 x 480), and minimum size of the total display area.

G 5.2.1.21 BS EN 16186-2:2017 sets out further requirements for integration of drivers’ cabdisplays, controls and indicators.

5.2.2 AWS/TPWS DMI controls and indications: colour specifications

5.2.2.1 AWS/TPWS DMI controls and indications provided on a panel shall meet thefollowing colour specifications:

• Yellow: Pantone Yellow C.• Red: Pantone 186C.

5.2.2.2 AWS/TPWS DMI controls and indications presented on a VDU shall comply with thecolour specifications for ETCS indications set out in ERA-ERTMS-015560.

Rationale

G 5.2.2.3 Readability: The specified colour parameters provide clear and distinctive colourswhich can readily be distinguished by the train driver, supporting readability of theAWS/TPWS controls and indications.

Guidance

5.3 AWS/TPWS DMI controls

5.3.1 AWS/TPWS DMI controls to be provided

5.3.1.1 The AWS/TPWS DMI shall provide the following controls:

a) AWS caution acknowledgement.b) AWS brake demand acknowledgement.

RSSB Page 49 of 133

c) SPAD brake demand acknowledgement.d) Overspeed brake demand acknowledgement.e) Brake release.f) Train stop override.g) TPWS temporary isolation.h) AWS isolation.i) AWS/TPWS isolation.

Rationale

G 5.3.1.2 Integration with train operations: The train driver uses the DMI controls to interactwith the AWS/TPWS to comply with the rules for train driving, which include thefollowing:

a) Acknowledgement of an AWS warning.b) Acknowledgement of a SPAD brake demand initiated by the TPWS.c) Acknowledgement of an overspeed brake demand initiated by the TPWS.d) Release of the train brake after a brake demand.e) Isolation of the AWS function, the TPWS function, or the AWS/TPWS functions.

Guidance on parameters

G 5.3.1.3 The AWS/TPWS DMI includes controls which are grouped together and incorporatedin a panel or VDU display and other controls which are provided as discrete devices onthe driver's desk or elsewhere in the rail vehicle.

G 5.3.1.4 Clauses 5.3.3 to 5.3.9 set out the parameter requirements for each control device,including:

a) Type.b) Appearance parameters: size, colour, luminance, shape, and labelling. The

appearance and labelling of the control devices helps the train driver to correctlydistinguish each control when operating the AWS/TPWS onboard subsystem.

c) Number of states or functions. Section 5.5 sets out the functional requirements foreach AWS/TPWS control.

d) Position: This parameter defines the position of the control device within the railvehicle and describes the layout of the AWS/TPWS DMI, which is relevant to itsease of use.

G 5.3.1.5 If a parameter is not relevant to a specific control device, this is shown as ‘notapplicable’.

G 5.3.1.6 If a parameter is relevant but it is not necessary to specify a prescriptive value to thatparameter, the value is shown as ‘unspecified’ and guidance on good practice isincluded.

G 5.3.1.7 The parameter 'size' for a button on a panel specifies the minimum size of thebutton, excluding any surrounding bezel.

G 5.3.1.8 When a panel-based DMI is provided, it is good practice to provide buttons thatdepress by at least 2 mm when operated and with a consistent resistance within therange 2.8 to 15 newtons.

of 133 RSSB

G 5.3.1.9 It is good practice for controls to provide audible and/or tactile feedback to the traindriver. Panel and soft key DMI solutions can inherently provide tactile feedback.

Guidance on labelling

G 5.3.1.10 Labelling of panels and other physical devices is designed to be readable, permanentand durable.

G 5.3.1.11 Good practice for labelling on a DMI panel so that it is readable provides lettering:

a) In capitals.b) In a sans serif font.c) With minimum character height of 5 mm.d) When viewed from the driving position, subtending as a minimum a visual angle

of 15 minutes.e) With high contrast against the panel background.

G 5.3.1.12 ERA_ERTMS_015560 version 3.6.0 sets out further requirements for labelling ofERTMS/ETCS DMI controls and indications.

5.3.2 AWS/TPWS DMI: cab layout

5.3.2.1 The controls described in 5.3.1.1 a) – f) shall be positioned so that the train driver caninteract with the controls from the normal driving position, without being impeded byother cab equipment, controls, or structures.

Rationale

G 5.3.2.2 Integration with train operations: The train driving task includes train driverinteraction with the AWS/TPWS DMI at any time. Any driving cab features thatobscure the controls and indications, or make interaction more difficult, wouldinfluence the likelihood of human error during train operations.

Guidance

G 5.3.2.3 Potential train driver errors include:

a) Accidental operation of an AWS/TPWS control whilst using other cab controls.b) Wrong operation of an AWS/TPWS control.

5.3.3 AWS caution acknowledgement control

5.3.3.1 The AWS caution acknowledgement control device parameters shall conform with thevalues set out in Table 4.

Parameter Value

Type Physical push button (self-restoring)

Size Unspecified

Colour Unspecified

Luminance Not applicable

RSSB Page 51 of 133

Parameter Value

Shape Unspecified

States Two:

a) Not operated (self-restored state)b) Operated (when fully depressed)

Position A discrete, 'primary control', located on thedriving desk in each driving cab

Located so that it can be operated from thenormal driving position and cannot beoperated by someone seated in another cabposition

Identity label Unspecified

Table 4: AWS caution acknowledgement control

Rationale

G 5.3.3.2 Integration with train operations: A discrete physical push button that is consistentlypositioned as a primary control on the train driver's desk can be located and operatedquickly. A control that cannot be located and operated quickly increases the likelihoodof delay in acknowledging an AWS warning and could result in an unnecessary brakeapplication.

G 5.3.3.3 Safe integration: Positioning the control so that it is only operable by someone in thenormal driving position is intended to control the likelihood of mis-use. If anotherperson operates the acknowledgement control, this might mean that the train driverhas not fully recognised the AWS warning, or observed the associated signal aspect orwarning sign.

Guidance

G 5.3.3.4 The train driver operates the AWS acknowledgment button in response to the AWSwarning audible indication, which sounds on the approach to lineside signalsdisplaying a cautionary aspect and lineside operational signs that are provided withan AWS permanent magnet. Therefore, this control needs to be robust and easy tooperate.

G 5.3.3.5 Providing the acknowledgement control as part of an integrated VDU-based DMIwould not be suitable for the quick, easy and positive response required.

G 5.3.3.6 The AWS caution acknowledgement control device is usually positioned on the right-hand side of the driving desk.

of 133 RSSB

Figure 2: Example designs of AWS caution acknowledgement control

5.3.4 Brake demand acknowledgement control

5.3.4.1 The AWS brake demand acknowledgement control device parameters shall conformwith the values set out in Table 5.

Parameter Value

Type Panel: Push button (self-restoring)

VDU based solution: Icon or soft key

Size Minimum diameter or width: 10 mm

Colour Yellow

Luminance Panel: Combined with AWS brake demand andacknowledgement indication

VDU based solution: Sufficiently bright in allexpected lighting conditions to be identifiableand to be differentiated from other AWS/TPWS controls and indications

RSSB Page 53 of 133

Parameter Value

Shape Panel: Circular

VDU based solution: Circular, rectangular orsquare

States Two:

a) Not operated (self-restored or enabledposition)

b) Operated (when pressed)

Position A ‘primary control’, located on the driving deskin each driving cab

Positioned close to and aligned with the SPADand overspeed brake demand indicators /acknowledgement controls

Positioned either below or to the right of theSPAD and overspeed brake demandacknowledgement controls

Touch screen VDU solution: When integratedinto the ERTMS/ETCS DMI; within DMI sub-areas ‘C’ or ‘G’

Soft key VDU solution: When integrated intothe ERTMS/ETCS DMI; a soft key positionednext to the identity labels in DMI sub-areas ‘F’or ‘H’

Identity label Panel: 'AWS'

VDU based solutions: ‘AWS’ legend positionedwithin the icon

Table 5: AWS brake demand acknowledgement control

5.3.4.2 The SPAD brake demand acknowledgement control shall conform with theparameters set out in Table 6.

Parameter Value

Colour Red

of 133 RSSB

Parameter Value

Luminance Panel: Combined with SPAD brake demand andacknowledgement indication

VDU based solution: Sufficiently bright in allexpected lighting conditions to be identifiableand to be differentiated from other AWS/TPWS controls and indications.

Number of states Two:

b) Operated (when fully depressed)

Positioned close to and aligned with the AWSand overspeed brake demand indicators /acknowledgement controls

Positioned either above or to the left of theAWS and overspeed brake demandacknowledgement controls

Identity label Panel: 'SPAD'

VDU based solutions: ‘SPAD’ legend positionedwithin the icon

Table 6: SPAD brake demand acknowledgement control

5.3.4.3 The overspeed brake demand control shall conform with the parameters set out inTable 7.

RSSB Page 55 of 133

Parameter Value

Colour Yellow

Luminance Panel: Combined with overspeed brakedemand and acknowledgement indication

Positioned close to and aligned with the AWSand SPAD overspeed brake demandacknowledgement controls

Positioned either below or to the right of theSPAD brake demand acknowledgement control

Identity label Panel: ‘OVERSPEED’

VDU based solutions: ‘TPWS OSS’ legendpositioned within the icon

Table 7: Overspeed brake demand control

of 133 RSSB

Rationale

G 5.3.4.4 Integration with train operations: Configuring the AWS/TPWS DMI so that the threebrake demand acknowledgement controls have similar characteristics, and areconsistently positioned together, supports the train driver in observing the correctprocedures following an AWS/TPWS brake intervention.

G 5.3.4.5 Interpretability: The red colour makes the SPAD brake demand acknowledgementcontrol visually distinctive from the other brake demand acknowledgement controls,which are coloured yellow. The colour red supports concept compatibility with a stopaspect; the colour yellow supports concept compatibility with signal aspects andindications that provide cautionary information.

Guidance

G 5.3.4.6 The SPAD or overspeed brake demand acknowledgement control is operated inconjunction with the brake release control following a TPWS brake demand. This isintended to confirm that the train driver has recognised the cause of the brakeapplication and has followed the appropriate operating procedures.

G 5.3.4.7 If the diameter of the brake demand acknowledgement control is less than 20 mm, itis good practice for the push button to protrude above the panel surface orsurrounding bezel by a distance greater than the operational stroke.

G 5.3.4.8 10 mm is compatible with the dimension specified in ERA-ERTMS-015560 for ERTMS/ETCS DMI sub-area ‘C’ or 'G'.

5.3.5 Brake release control

5.3.5.1 The brake release control shall conform with the parameters set out in Table 8.

Parameter Value

Type Panel: Push button (self-restoring),incorporating a self-closing, hinged cover

VDU based solution: outlined ‘target’ or softkey; disabled until the preconditions for brakerelease are satisfied

Colour Panel: Black

Touch screen or soft key VDU:

a) Disabled: grey target area with black textb) Enabled: white target area with black text

RSSB Page 57 of 133

Parameter Value

Luminance Panel: not applicable

VDU based solution: Sufficiently bright in allexpected lighting conditions to be identifiableand to be differentiated from other AWS/TPWS controls and indications.

Positioned close to brake demand indicators/acknowledgement controls

Soft key VDU solution: When integrated intothe ERTMS/ETCS DMI; a soft key positionednext to the identity label within DMI sub-areas‘F’ or ‘H’

Identity label Panel based solution: ‘BRAKE RELEASE’

VDU based solutions: ‘Brake Rel’ legendpositioned within the icon

Table 8: Brake release control

Rationale

G 5.3.5.2 Safe integration: The design of the brake release control is intended to:

a) Protect against accidental operation of the brake release.b) Require a conscious decision to depress the brake release button.

G 5.3.5.3 Integration with train operations: Configuring the AWS/TPWS DMI so that the brakerelease control is positioned close to the brake demand acknowledgement controlssupports the train driver in observing the correct procedures following an AWS/TPWSbrake intervention.

of 133 RSSB

G 5.3.5.4 Interpretability: The black colour makes the brake release control visually distinctivefrom the other AWS/TPWS DMI controls.

Guidance

G 5.3.5.5 The train driver operates the brake release control and the control associated with therelevant brake demand indication; this is intended to confirm that the driver hasrecognised the cause of the brake application, informed the signaller, and carried outappropriate procedures.

G 5.3.5.6 10 mm is compatible with the dimension specified in ERA-ERTMS-015560 for ETCSDMI sub area ‘C’ or 'G'.

G 5.3.5.7 Some AWS/TPWS DMI panel implementations have incorporated a brake releasebutton that is 18 mm (minimum) diameter, which is larger than the minimum sizedefined in ERA-ERTMS-015560. Using ETCS DMI sub-area ‘G’ would replicate thelarger size of this control on the panel-based solution.

5.3.6 Train stop override control

5.3.6.1 The train stop override control shall conform with the parameters set out in Table 9.

Parameter Value

Type Panel: Push button (self-restoring), which doesnot protrude above the panel surface or anysurrounding bezel

VDU based solution: Icon or soft keyincorporating a 2 s delay

Size Minimum width: 10 mm

Colour Panel: Yellow

VDU based solution: see Table 17 forassociated indication

Luminance Panel: Combined with the train stop overrideindication

Shape Panel: Square

VDU based solution: Rectangular or square

RSSB Page 59 of 133

Parameter Value

b) Operated (when pressed).

Combined with the train stop override visualindication

Soft key VDU solution: When integrated intothe ERTMS/ETCS DMI; a soft key positionednext to the identity label within DMI sub-areas‘F’ or ‘H’

Identity label Panel: ‘TRAIN STOP OVERRIDE’

VDU based solutions: ‘TSO’ legend positionedwithin the icon

Table 9: Train stop override control

Rationale

G 5.3.6.2 Integration with train operations: The design of the button control and the 2 s delayon a VDU control avoids the likelihood that a train driver will inadvertently operatethe train stop override control.

G 5.3.6.3 Interpretability: The identity label makes the train stop override control visuallydistinctive from the other AWS/TPWS DMI controls.

Guidance

G 5.3.6.4 This control overrides the TPWS train stop function for a limited time to allow thetrain to pass a signal at danger without initiating a TPWS brake application.

G 5.3.6.5 10 mm is compatible with the dimension specified in ERA-ERTMS-015560 for ETCSDMI sub area ‘C’ or 'G'.

G 5.3.6.6 Legacy AWS/TPWS DMI panel implementations have incorporated a train stopoverride button that is 17 mm (minimum) wide, which is larger than the minimumsize defined in ERA-ERTMS-015560. Using ETCS DMI sub-area ‘G’ would replicate thelarger size of this control on the panel-based solution.

G 5.3.6.7 Good practice for a VDU based DMI is to display a text message prompt to remindthe train driver of the 2 s delay, for example 'Press and hold the TSO for 2 s to

of 133 RSSB

activate the train stop override', that appears when the train stop override control ispressed.

5.3.7 TPWS temporary isolation control

5.3.7.1 The TPWS temporary isolation control shall conform with the parameters set out inTable 10.

Parameter Value

Type A centre-biased ON/OFF switch

Size Not specified

Colour Not specified

Shape Not specified

a) Normalb) Isolated

Position On the rail vehicle in a position that isaccessible to the train driver

If provided within driving cab, sited out ofreach of the train driver when in the normaldriving position

Identity label ‘TPWS TEMPORARY ISOLATION’ with twooperating positions labelled ‘NORMAL’ and‘ISOLATE'

Table 10: TPWS temporary isolation control

Rationale

G 5.3.7.2 Safe integration: The position of the TPWS temporary isolation control is intended toreduce the likelihood that it will be operated during normal train operations. Isolatingthe TPWS function might increase SPAD risk and overspeed risk to an unacceptablelevel. Operating a train with an isolated TPWS onboard subsystem without authoritywould be a contravention of the Railway Safety Regulations 1999.

Guidance

G 5.3.7.3 Temporary isolation of TPWS allows the train to pass several signals at dangerwithout needing to use the train stop override at each signal. It can be used insituations such as temporary block working or emergency special working.

G 5.3.7.4 The rules for operating the TPWS temporary isolation control are set out in theGERT8000 Rule Book.

RSSB Page 61 of 133

G 5.3.7.5 Further requirements for the security of the isolation controls for train safety systemsare set out in GMRT2185.

5.3.8 AWS isolation control

5.3.8.1 The AWS isolation control shall conform with the parameters set out in Table 11.

Parameter Value

Type Physical switch

Size Not specified

Shape Not specified

If provided within driving cab, sited out ofreach of the train driver when in the normaldriving position

Identity label 'AWS' with two positions labelled 'NORMAL'and 'ISOLATE'

Table 11: AWS isolation control

Rationale

G 5.3.8.2 Safe integration: The position of the AWS isolation control is intended to reduce thelikelihood that it will be operated during normal train operations. Removing the AWSfunctionality might increase SPAD risk and overspeed risk.

G 5.3.8.3 Integration with train operations: In some failure scenarios it might be necessary toisolate the AWS on the rail vehicle to move the train. When AWS needs to be isolatedbecause of a fault which affects only the AWS onboard subsystem, independentisolation of AWS makes it possible to keep TPWS operational and retain theprotection given by TPWS.

Guidance

G 5.3.8.4 A rail vehicle fitted with AWS has one AWS isolation control; this includes rail vehiclesthat have two driving cabs. A multiple unit is fitted with two AWS isolation controls,one for each AWS fitted rail vehicle.

of 133 RSSB

G 5.3.8.5 The rules for isolating and de-isolating the AWS are set out in the GERT8000 RuleBook.

5.3.9 AWS/TPWS isolation control

5.3.9.1 The AWS/TPWS isolation control shall conform with the parameters set out in Table 12.

Parameter Value

Type Physical switch

Size Not specified

Shape Not specified

If provided within driving cab, sited out of thereach of the train driver when in the normaldriving position

Visibility Not specified

Identity label 'AWS/TPWS' with two positions labelled'NORMAL' and 'ISOLATE'

Table 12: AWS/TPWS isolation control

Rationale

G 5.3.9.2 Safe integration: The position of the AWS/TPWS isolation control is intended toreduce the likelihood that it will be operated during normal train operations.Removing the AWS and TPWS functionality might increase SPAD risk and overspeedrisk. Operating a train with an isolated TPWS onboard subsystem without authoritywould be a contravention of the Railway Safety Regulations 1999.

G 5.3.9.3 Integration with train operations: In some failure scenarios it might be necessary toisolate the AWS and TPWS on the rail vehicle to move the train.

Guidance

G 5.3.9.4 This control provides a means of completely isolating the AWS and TPWSfunctionality on the rail vehicle so that it can be moved.

RSSB Page 63 of 133

G 5.3.9.5 The isolation control may be duplicated on rail vehicles that have more than onedriving cab.

G 5.3.9.6 The rules for isolating and de-isolating the AWS/TPWS are set out in the GERT8000Rule Book.

5.4 AWS/TPWS DMI indications

5.4.1 AWS/TPWS DMI indications to be provided

5.4.1.1 The AWS/TPWS DMI shall provide the indications set out in Table 13.

Type Indicationformat

Meaning (information conveyed)

Audible Horn AWS warning

Visual Black andyellow(sunflower)

AWS warning acknowledged

Audible Bell AWS clear

Visual Flashingyellow light

AWS brake demand NOT acknowledged

Steady yellowlight

AWS brake demand acknowledged

Visual +audible

Flashing redlight

SPAD brake demand NOT acknowledged

Tone + voicemessage

Visual Steady redlight

SPAD brake demand acknowledged

Visual +audible

Flashingyellow light

Overspeed brake demand NOT acknowledged

Tone + voicemessage

Visual Steady yellowlight

Overspeed brake demand acknowledged

TPWS train stop override control operated

TPWS onboard subsystem is temporarilyisolated

of 133 RSSB

Type Indicationformat

Meaning (information conveyed)

Visual Flashingyellow light

AWS/TPWS fault detected

Visual Open point -see 5.4.8

AWS onboard subsystem is isolated

Table 13: AWS/TPWS DMI indications

Rationale

G 5.4.1.2 Integration with train operations: The train driver uses the DMI indications to obtaininformation necessary to comply with the train driving rules.

Guidance

G 5.4.1.3 The AWS/TPWS DMI includes indications which are grouped together andincorporated in a panel or VDU display and other indications which are provided asdiscrete devices on the train driver's desk or elsewhere in the rail vehicle.

G 5.4.1.4 The requirements in 5.4.2 to 5.4.8 set out further requirements for each AWS/TPWSindication. The requirements specify the audible parameters and visual appearanceparameters that help the train driver to correctly distinguish and interpret theindications being given.

G 5.4.1.5 If a parameter is not relevant to a specific indication, this is shown as ‘notapplicable’.

G 5.4.1.6 If a parameter is relevant but it is not necessary to specify a prescriptive value to thatparameter, the value is shown as ‘unspecified’ and guidance on good practice isincluded.

G 5.4.1.7 The parameter 'size' for an indication on a panel specifies the minimum size of thelens or illuminated area, excluding any surrounding bezel.

5.4.2 Audibility of AWS/TPWS indications

5.4.2.1 The volume of the AWS and TPWS audible indications shall be within the range65 dBA to 95 dBA and be at least 6 dB above ambient, measured at all drivingpositions in the cab.

5.4.2.2 The AWS/TPWS DMI audible indications shall conform with the parameters set out inTable 14.

RSSB Page 65 of 133

Identity Parameter Value(s)

AWS warning Frequency 800 Hz (+/- 20 Hz)

Tone/harmonics

Single, steady tuned tone

Speechcontent

Not applicable

Duration Continuous until the AWS warningacknowledgement control is operated

AWS clear Frequency 1200 Hz (+/- 30 Hz)

Tone/harmonics

Simulated chime or ringing bell

Speechcontent

Not applicable

Duration 0.5 to 1.5 s

SPAD brakedemand

Frequency Priming tone followed by speech message:‘SPAD alert, contact the signaller’

Sound file on RSSB website at https://www.rssb.co.uk/Library/standards-and-the-rail-industry/sound-files/priming-tone-plus-spad.wav

Tone/harmonics

Speechcontent

Duration Continuous until the SPAD brake demandacknowledgement control is operated

Volume After 60 s: Volume reduced by 6 dB

Overspeedbrake demand

Frequency Priming tone followed by speech message:‘Overspeed, contact the signaller’

Sound file on RSSB website at https://www.rssb.co.uk/Library/standards-and-the-rail-industry/sound-files/priming-tone-plus-overspeed.wav

Tone/harmonics

Speechcontent

Duration Continuous until the overspeed brake demandacknowledgement control is operated, or untila SPAD brake demand occurs

Volume After 60 s: Volume reduced by 6 dB

Table 14: AWS and TPWS audible indications

of 133 RSSB

Rationale

G 5.4.2.3 Audibility: The volume supports and influences audibility of the presented indicationsin the operational context.

G 5.4.2.4 Interpretability: The speech messages are provided to reinforce the train driver'sunderstanding that the brake demand on the train has been initiated by the TPWSand to distinguish between a SPAD alert and an overspeed alert.

G 5.4.2.5 Interpretability: The format of the SPAD and overspeed brake demand audibleindications means that the priming tone precedes the relevant speechannouncement. The tone and speech announcement do not sound simultaneouslybecause this would adversely affect interpretability.

G 5.4.2.6 Train driver learning: Providing consistent and distinctive AWS/TPWS audibleindications, which are differentiated from other audible indications in the cabsupports train driver learning and knowledge retention.

G 5.4.2.7 Integration with train operations: When the train has come to a stand, the train driveris required to contact the signaller. If for some reason the train driver has notacknowledged the alert, or is unable to, the speech message continues but reduces involume after one minute to reduce the likelihood that it will interfere withcommunication between the train driver and the signaller.

Guidance

G 5.4.2.8 The AWS audible indication is the primary indication that AWS gives to the traindriver, which the driver interprets as part of the train driving task.

G 5.4.2.9 The TPWS audible indications are presented together with a visual indication and abrake application.

G 5.4.2.10 The two AWS audible indications approximate to the audible indications generatedusing the technology available when the AWS was first implemented on rail vehicles:

a) The AWS warning indication was generated by passing the air escaping from thebrake pipe through a tuned horn.

b) The AWS clear indication was generated by an electro-mechanical bell.

This technology is still used in some heritage rail vehicles; however, on most railvehicles the AWS audible indications are generated using electronic components.

G 5.4.2.11 RSSB research report T902 provides further information about the SPAD andoverspeed audible indications. The key components of these alarms are:

a) A priming tone, which is a 3-pulse tone with a fundamental frequency of 440 Hz,with regular harmonics at 880, 1320, 1760 and 2220 Hz. Each of the pulses is300 ms in length with no time intervals between them, resulting in a length of900 ms for the complete priming tone. In order to avoid a startle response, eachpulse is subject to an Attack-Sustain-Decay-Release (ASDR) amplitude envelope.

b) A female voice was chosen for the speech messages because the female voice ismore suitable where there is considerable low frequency noise, which is the casefor train cabs. A non-urgent, relatively monotonic style with no stress on anywords, evenly paced syllables and clear enunciation is used.

RSSB Page 67 of 133

G 5.4.2.12 The TSI LOC & PAS sets out further requirements for the audibility of cab indications.

G 5.4.2.13 The TSI Noise sets out further requirements for measuring ambient sound levels.

G 5.4.2.14 RIS-0797-CCS and RIS-0798-CCS set out further requirements for the volume of ETCSonboard subsystem audible indications.

5.4.3 Luminance of AWS/TPWS DMI lit indications

5.4.3.1 The luminance of the AWS/TPWS lit indications shall be sufficient so that they arereadable over the full range of ambient cab lighting levels.

Rationale

G 5.4.3.2 Readability: Luminance supports and influences the readability of lit indications in theoperational context.

Guidance

G 5.4.3.3 Train drivers will read and interpret the AWS/TPWS indications throughout the rangeof cab lighting conditions applicable to the rail vehicle when it is being driven as atrain. Excessive luminance of lit indications is a problem if a lit indication distracts thetrain driver from the train driving task or obscures another cab indication that needsto be read. Excessive luminance is more likely to be a problem when trains are drivenin dark environments.

G 5.4.3.4 A means of adjusting the indication luminance may be provided to accommodate therange of ambient light levels experienced in the operational context. The range ofadjustment provides a means for the train driver to set the luminance at a level sothat the lit indications can be easily read without reducing the luminance to the pointwhere the information being presented cannot be reliably interpreted.

G 5.4.3.5 RIS-0797-CCS and RIS-0798-CCS set out further requirements for luminance of ETCScab indications.

5.4.4 Visual indication parameters: AWS warning acknowledged

5.4.4.1 The ‘AWS warning acknowledged’ indication ('sunflower') shall conform with theparameters set out in Table 15.

Parameter Values

Overall appearance A circular symmetrical image, incorporatingmultiple yellow sectors of equal size andspacing, contrasted against a blackbackground

Colour Sectors: yellow

Background: black

of 133 RSSB

Parameter Values

Shape Indication: circular

Yellow sectors: minimum 8, maximum 10, allthe same shape

Yellow sector angle: 11° to 18°

Size Indication outer diameter: minimum 42 mm

All yellow sectors of equal size

Yellow sector width: equal to, or narrower than,the sector spacing

Yellow sector outer dimension: 5 mm (+/- 1 mm) less than the indication outer diameter

Yellow sector inner diameter: 15 to 20 mm

Display element spacing All sectors equally spaced

Sector spacing: equal to, or greater than, thesector width

a) Displayed (‘black and yellow’)b) Not displayed (‘all black’)

Flashing rate Steady, non-flashing appearance

Position Sited within the cab so that the displayedindication is clearly visible from the drivingposition to which it applies, when looking atthe track ahead

When integrated into the ERTMS/ETCS DMIVDU screen: Within DMI sub-area ‘D’

Identity label Not applicable

Table 15: AWS warning acknowledged indication ('sunflower')

5.4.4.2 Where duplicate indicators are provided in the same driving cab, the ‘AWS warningacknowledged’ indications shall be synchronised in their operation.

Rationale

G 5.4.4.3 Readability: The minimum specified dimensions support readability of the indication.

G 5.4.4.4 Interpretability: Providing an ‘AWS warning acknowledged’ indication that has aconsistent and distinctive appearance supports interpretability in the context of thetrain driving task, supports train driver learning and knowledge retention.

RSSB Page 69 of 133

Guidance

G 5.4.4.5 If a cab is provided with two driving desks, a separate indicator may be needed oneach desk to support readability of the AWS warning acknowledged indication fromeach driving position.

G 5.4.4.6 Section 5.6.3 sets out the functional requirements for the AWS warningacknowledged visual indication.

G 5.4.4.7 The ‘all black’ display is continuously shown:

a) When the last AWS indication was a clear indication.b) When an AWS warning audible indication has been given, before the AWS caution

acknowledgement control has been operated.

G 5.4.4.8 The appearance of this indication is derived from the original design of the electro-mechanical AWS indicator, which incorporated a fixed plate perforated withsegmental slots and a rotating disc with black and yellow sectors, which showedthrough the slots. This technology is still used in some heritage rail vehicles; however,on most rail vehicles the indication is generated using electronic components.

G 5.4.4.9 An indication larger than 42 mm diameter might be necessary to achieve a displaythat is readable. Some rail vehicles are still fitted with an electro-mechanical indicatorthat presents an indication that is up to 90 mm in diameter, incorporating 10 yellowsectors.

G 5.4.4.10 Size, luminance, the number of yellow sectors and sector spacing combine toinfluence the readability of this indication and its prominence relative to other cabfeatures.

G 5.4.4.11 An indication comprising eight yellow sectors and a 42 mm diameter has beensuccessfully implemented on rail vehicles that incorporate either:

a) A panel based DMI solution using LED technology.b) A VDU based DMI solution, which presents the indication directly in front of the

train driver.

G 5.4.4.12 When presented in the form of an image within an integrated ETCS DMI display, it isgood practice to highlight the area with a grey border so that the 'all black' circle isvisible.

G 5.4.4.13 The distinctive appearance of the ‘sunflower’ display means that there is no need toprovide an identity label.

G 5.4.4.14 Figure 3 shows an example of an ‘AWS warning acknowledged’ indicationincorporating eight yellow sectors.

of 133 RSSB

Figure 3: Example of the AWS warning acknowledged indication ('sunflower')

5.4.5 Visual indication parameters: Brake demand and acknowledgement indications

5.4.5.1 The AWS, SPAD and overspeed brake demand and acknowledgement indicationsshall conform with the parameters set out in Table 16.

Parameter Values

Overall appearance Coloured lit indication

Colour AWS: yellow

SPAD: red

Overspeed: yellow

RSSB Page 71 of 133

Parameter Values

Shape and spacing Panel and touch screen VDU:

a) AWS indications integrated with AWS brakedemand acknowledgement control

b) SPAD indications integrated with SPADbrake demand acknowledgement control

c) Overspeed indications integrated withoverspeed brake demandacknowledgement control

Soft key VDU based solution: circular,rectangular or square, positioned next to therelevant soft key control

Number of states Three:

a) Unlitb) Lit, steadyc) Lit, flashing

Flashing rate Lit, steady: Steady, non-flashing appearance

Lit, flashing: 2 Hz ± 0.25 Hz with a 50% ± 5%duty cycle

Position Within the AWS/TPWS panel or VDU screenarea.

Panel and touch screen VDU based solution:

a) AWS indication integrated with the AWSbrake demand acknowledgement control

b) SPAD indications integrated with the SPADbrake demand acknowledgement control

c) Overspeed indications integrated with theoverspeed brake demandacknowledgement control

Soft key VDU based solution: The indicationshall be presented in DMI sub-area 'F' or 'H',next to the relevant soft key control device

Identity label Labelling for associated brake demandacknowledgement control as set out in Table 5(AWS), Table 6 (SPAD) and Table 7 (overspeed)

Table 16: Brake demand and acknowledgement indications

of 133 RSSB

Rationale

G 5.4.5.2 Interpretability: The red indication makes the SPAD brake demand visually distinctivefrom the other brake demand indications, which are coloured yellow. The colour redsupports concept compatibility with a stop aspect; the colour yellow supports conceptcompatibility with signal aspects and indications that provide cautionary information.The initial flashing state is intended to attract the train driver's attention to the AWS/TPWS brake demand and to serve as a reminder that action is necessary. The steadyindication continues to remind the train driver of the cause of the brake applicationand confirms that the brake demand has been acknowledged.

G 5.4.5.3 Train driver learning: The consistent layout and appearance of the brake demand andacknowledgement indicators, and their integration into the associated controldevices, support train driver learning and knowledge retention.

G 5.4.5.4 Interpretability: Incorporating the indication into or next to the control device helpsthe train driver to correctly identify the applicable control.

Guidance

G 5.4.5.5 This standard specifies three separate brake demand indications, which enable thetrain driver to confirm the cause of the brake application. To release the brakesfollowing a brake demand, the relevant brake demand acknowledgement control isoperated in conjunction with the brake release control.

G 5.4.5.6 Initial TPWS onboard subsystem designs provided one brake demand indication,which did not enable the train driver to distinguish between SPAD or overspeedcauses. The same indication also indicated a brake application due to a failure toacknowledge an AWS warning.

G 5.4.5.7 10 mm is compatible with the dimension specified in ERA-ERTMS-015560 for ETCSDMI sub area ‘C’.

5.4.6 Visual indication parameters: Train stop override indication

5.4.6.1 The train stop override indication shall conform with the parameters set out in Table 17.

Parameter Values

Colour Panel: Yellow

VDU based solution: when 'lit', yellow withblack lettering; when 'unlit', black with whitelettering

Shape Panel: Square

VDU: Rectangular or square

Spacing Not applicable

RSSB Page 73 of 133

Parameter Values

Size Minimum width: 10 mm

a) Unlitb) Lit, steady

Flashing rate Not applicable

Position Within the AWS/TPWS panel or VDU screenarea

Panel and touch screen VDU based solution:integrated with the ‘train stop override’ control

Soft key VDU based solution: The indicationshall be presented in DMI sub-area 'F' or 'H',next to the relevant soft key control device

Identity label Labelling for train stop override control as setout in Table 9

Table 17: Train stop override indication

Rationale

G 5.4.6.2 Interpretability: The rectangular shape makes the train stop override indication on apanel visually distinctive from the other AWS/TPWS DMI indications, which arecircular.

Guidance

G 5.4.6.3 The train driver uses the lit train stop override indication to confirm that the train stopoverride is effective, so that the train will be able to pass a signal at danger withoutbeing tripped by TPWS.

G 5.4.6.4 When the train stop override time has expired, the lit indication is extinguished.

G 5.4.6.5 10 mm is compatible with the dimension specified in ERA-ERTMS-015560 for ETCSDMI sub-area ‘C’.

G 5.4.6.6 Legacy AWS/TPWS DMI panel implementations have incorporated a train stopoverride indicator that is larger than the minimum size defined in ERA-ERTMS-015560. Using ETCS DMI sub-area ‘G’ would replicate the larger size of thisindicator on the panel-based solution.

5.4.7 Visual indication parameters: TPWS temporary isolation/fault indication

5.4.7.1 The TPWS temporary isolation/fault indications shall conform with the parametersset out in Table 18.

of 133 RSSB

Parameter Values

Colour Yellow

VDU-based solution: Circular, rectangular orsquare

Spacing Not applicable

Number of states Three:

a) Unlitb) Lit steady (TPWS temporary isolation)c) Lit flashing (fault)

Flashing rate Lit steady: Steady, non-flashing appearance

Lit flashing: 2 Hz ± 0.25 Hz with a 50% ± 5%duty cycle

Position Within the AWS/TPWS panel or VDU screenarea

A ‘primary indication’ positioned close to andaligned with the ‘train stop override’ and‘brake release’ controls

Panel: Positioned either above or to the left ofthe ‘train stop override’ control

Integrated into the ETCS DMI touch screen:Within DMI sub-area ‘C’ or ‘G’

Identity label Panel: ‘TEMPORARY ISOLATION / FAULT

VDU based solution:

a) ‘ISOL’ when lit steadyb) ‘FAULT’ when lit flashing

Table 18: TPWS temporary isolation/fault indication

Rationale

G 5.4.7.2 Interpretability: The distinctive appearance makes the TPWS temporary isolation/fault indications visually distinctive from the other AWS/TPWS DMI indications. Thetemporary isolation indication is provided to remind the driver that TPWS has beenisolated, and that it should be restored to use when the train reaches the end of thesection for which the temporary isolation was authorised. The flashing indication

RSSB Page 75 of 133

makes the TPWS ‘fault’ conspicuous and differentiates it from the temporaryisolation indication.

G 5.4.7.3 Integration with train operations: The three states are provided to help the traindriver decide whether the TPWS onboard subsystem is operating correctly, is failed, oris temporarily isolated.

Guidance

G 5.4.7.4 When the indication is unlit, the TPWS is operating correctly and is not isolated.

G 5.4.7.5 When the TPWS system detects a fault, or when the AWS/TPWS onboard subsystemstart-up test is not successfully completed, the indication flashes to inform the traindriver that the onboard subsystem is in a failed state.

G 5.4.7.6 The steady indication informs the train driver that the TPWS onboard subsystem hasbeen temporarily isolated.

G 5.4.7.7 10 mm is compatible with the dimension specified in ERA-ERTMS-015560 for ETCSDMI sub-area ‘C’.

G 5.4.7.8 Legacy AWS/TPWS DMI panel implementations have incorporated an indicator thatis larger than the minimum size defined in ERA-ERTMS-015560. Using ETCS DMI sub-area ‘G’ would replicate the larger size of this indicator on the panel-based solution.

5.4.8 Visual indication parameters: AWS isolation/fault indication

5.4.8.1 [Open Point]

Rationale

G 5.4.8.2 Integration with train operations: Train drivers need to understand whether the AWSonboard subsystem is operating correctly, is failed or is isolated.

Guidance

G 5.4.8.3 GMRT2185 sets out further requirements for indicating AWS isolation.

G 5.4.8.4 This open point can be closed by either:

a) Integrating the AWS isolation/fault indication with the ‘TPWS temporaryisolation/fault indication’.

b) Providing a separate indicator with the same visual characteristics as the ‘TPWStemporary isolation/fault indication’. In this case, the AWS and TPWS isolation/fault indication labels include the qualifiers ‘AWS’ and ‘TPWS’.

G 5.4.8.5 The option chosen should consider any rules that require train drivers to distinguishbetween a failure that affects the TPWS or the AWS or the AWS/TPWS.

5.5 AWS/TPWS DMI control functions

5.5.1 AWS caution acknowledgement control function

5.5.1.1 Operating the AWS caution acknowledgement button shall:

of 133 RSSB

a) Acknowledge the AWS audible warning.b) Prevent the application of the train brakes if the control is operated within the

caution acknowledgement delay period.

5.5.1.2 It shall not be possible to acknowledge an AWS warning by:

a) Permanently operating the AWS caution acknowledgement button.b) Operating the AWS caution acknowledgement button before the ‘restrictive

response state’ is entered.c) Operating the AWS brake demand acknowledgement control.

Rationale

G 5.5.1.3 Safe integration: The AWS is designed to prevent an AWS acknowledgement beingstored, which would increase the likelihood of a SPAD or an overspeed event.

G 5.5.1.4 Integration with train operations: The train driver operates the AWS cautionacknowledgement button to confirm awareness of the cautionary signal aspect orwarning sign to which it applies.

G 5.5.1.5 Train driver learning: Designing the system so that an AWS warning is acknowledgedonly by operating the AWS caution acknowledgement button supports train driverlearning and knowledge retention, so that the method of acknowledgement isconsistent for all implementations.

Guidance

G 5.5.1.6 The response of the AWS warning acknowledged indication to the operation of theAWS caution acknowledgement control is applicable irrespective of whether a brakedemand has been initiated. Section 5.6.3 sets out further requirements for theindication response.

G 5.5.1.7 If the train driver does not acknowledge the AWS warning within the specifiedcaution acknowledgement delay period, the train brakes are automatically applied.

G 5.5.1.8 GERT8075 sets out requirements for the caution acknowledgement delay period andthe AWS ‘restrictive response state’.

5.5.2 Independence of AWS caution acknowledgement control function from TPWSfunctionality

5.5.2.1 Operating the AWS caution acknowledgement button shall not acknowledge a SPADbrake demand or an overspeed brake demand.

Rationale

G 5.5.2.2 Safe integration: Maintaining functional independence between the AWS cautionacknowledgement and the TPWS brake demand acknowledgement functionssupports the train driver in recognising the cause of a brake demand so that thecorrect procedures are followed.

RSSB Page 77 of 133

Guidance

5.5.3 TPWS train stop override control function

5.5.3.1 Operating the train stop override control shall activate the train stop overridefunction until one of the following criteria is met:

a) The TPWS onboard subsystem detects an active TSS loop.b) A pre-set time, not exceeding 60 s, has elapsed since the train stop override

control was operated.

5.5.3.2 Continuously depressing the train stop override button shall not extend the time thatthe override function is active.

Rationale

G 5.5.3.3 Safe integration: The TPWS override function provides a means for the train driver topass a TPWS fitted signal at danger without the train brake being activated by theTPWS. The TPWS is designed to prevent incorrect operation, which would increase thelikelihood of an operating incident. Disabling the override function as soon as a TSS isdetected, or after a pre-set time, prevents a train driver from selecting and storing anoverride for future use. The override function is therefore effective only if it isoperated immediately before passing the signal at danger, so that the use of thisfacility is clearly associated with the signal concerned.

Guidance

G 5.5.3.4 The pre-set time needs to be long enough for a train to pass a signal and associatedTSS loop after the TPWS train stop override button has been pressed.

G 5.5.3.5 A pre-set time of 20 s is used for passenger trains.

G 5.5.3.6 A pre-set time of 60 s is used for locomotives that operate freight trains.

G 5.5.3.7 Where a locomotive is used for passenger and freight train operations, the pre-settime can take account of the needs of freight train operations.

5.5.4 TPWS start-up control functions

5.5.4.1 When a cab is made operational:

a) The AWS/TPWS power-up test shall be initiated.b) Any TPWS override and temporary isolation functions previously applied shall be

automatically removed.c) Any detected TPWS onboard subsystem faults shall be indicated.

Rationale

G 5.5.4.2 Safe integration: When a cab is made operational, the train driver needs to know thatthe TPWS onboard subsystem is operating correctly so that it can provide thenecessary train protection functionality.

of 133 RSSB

Guidance

G 5.5.4.3 Section 5.7 sets out further requirements for the AWS/TPWS power-up test.

5.5.5 Brake release control function

5.5.5.1 Following a brake application initiated by the AWS/TPWS, the train brakes shallrelease only when the following conditions are satisfied:

a) The brake demand has been acknowledged.b) 59 s have elapsed after the AWS/TPWS has initiated the brake application.c) After the 59 s has elapsed, either:

i) On a panel based solution, the relevant brake demand acknowledgementcontrol and the brake release control are operated together, or

ii) On a VDU based solution, the relevant brake demand acknowledgementcontrol is operated and then, within 5 s, the brake release control device isoperated.

5.5.5.2 The brake release conditions set out in 5.5.5.1 shall be maintained if power to theAWS/TPWS onboard subsystem is removed and restored.

Rationale

G 5.5.5.3 Safe integration: The AWS/TPWS DMI is designed to control the likelihood of anunwanted event due to a train driver incorrectly releasing the train brakes following abrake demand. The brake release function is designed to assist train drivers inapplying the correct procedures following an AWS/TPWS brake demand. It is not usedfor any other purpose.

G 5.5.5.4 Safe integration: Requiring the train driver to select and operate the relevant brakeacknowledgement control at the same time as the brake release control is intended toreinforce the reason for the train brake being applied.

G 5.5.5.5 Safe integration: Delaying the effectiveness of the brake release function for 59 sprovides enough time for:

a) The train brake to be effective in decelerating the train.b) The train driver to interpret the presented brake demand indication and

understand that the train brake application is due to an AWS/TPWS initiatedbrake demand.

G 5.5.5.6 Safe integration: The AWS/TPWS is designed so that the train driver cannot shortcutthe brake release functionality by shutting down and restoring the subsystem.

Guidance

G 5.5.5.7 The AWS/TPWS brake demand results in an emergency (or where available enhancedemergency) brake application. In many cases, 59 s is enough time for the train tostop. If the train has not fully stopped after 59 s, it will have significantly reducedspeed.

RSSB Page 79 of 133

G 5.5.5.8 The relevant brake demand acknowledgement control device is the device associatedwith the activated brake demand indication at the time that the train brake isapplied. These are:

a) AWS brake demand acknowledgement control.b) SPAD brake demand acknowledgement control.c) Overspeed brake demand acknowledgement control.

G 5.5.5.9 The VDU based solution incorporates a 5 s time limit because the technology maynot permit simultaneous operation of two controls, recognising that the intention isto operate the two controls together.

5.5.6 Brake release control function in the event of multiple AWS/TPWS brake demands

5.5.6.1 When the AWS brake demand indication and the overspeed brake demand indicationare lit at the same time, operating the overspeed brake demand acknowledgementcontrol with the brake release control shall:

a) Release the train brakes.b) Extinguish both brake demand indications.

5.5.6.2 When the AWS brake demand indication and the overspeed brake demand indicationare lit at the same time, operating the AWS brake demand acknowledgement controlwith the brake release control shall:

a) Extinguish the AWS brake demand indication.b) Not release the train brakes.c) Not extinguish the overspeed brake demand indication.

Rationale

G 5.5.6.3 Safe integration: The DMI is designed to draw attention to the TPWS overspeedintervention, to assist the train driver in applying the correct procedures whenreleasing the train brake.

G 5.5.6.4 Interpretability: The AWS provides additional audible and visual indications which areintended to elicit another, separate train driver response. The AWS visual indication ismaintained after the brakes have been released to remind the train driver that anAWS warning has been received and acknowledged.

Guidance

5.6 AWS/TPWS indication functions

5.6.1 AWS clear indication

5.6.1.1 The AWS clear audible indication shall start to sound when the AWS/TPWS onboardsubsystem enters the AWS clear signal response state.

of 133 RSSB

Rationale

G 5.6.1.2 Interpretability: The AWS clear indication (bell) is consistent with an unrestrictedproceed signal aspect.

Guidance

G 5.6.1.3 The train driver does not acknowledge the AWS clear audible indication.

G 5.6.1.4 GERT8075 sets out further information about the AWS clear signal response state.

5.6.2 AWS warning indication

5.6.2.1 The AWS warning audible indication shall start to sound when the AWS/TPWSonboard subsystem enters the AWS restrictive response state.

Rationale

G 5.6.2.2 Interpretability: The AWS warning indication (horn) assists the train driver to correctlyobserve the cautionary signal aspect or warning sign to which it applies.

Guidance

G 5.6.2.3 The AWS warning audible indication (horn) is the only form of warning given by theAWS. It continues to sound until it is acknowledged. The AWS visual indication is onlydisplayed when the audible indication has been acknowledged.

G 5.6.2.4 GERT8075 sets out further information about the AWS restrictive response state.

5.6.3 AWS acknowledgement indication functions

5.6.3.1 When the AWS caution acknowledgement control is operated:

a) The AWS warning audible indication (horn) shall be silenced within 100 ms.b) The AWS warning acknowledged visual indication (sunflower) shall be displayed

within 100 ms.

Rationale

G 5.6.3.2 Interpretability: The train driver uses the change to the AWS indications to confirmthat the AWS warning has been acknowledged.

G 5.6.3.3 Train driver learning: A consistent AWS indication response supports train driverlearning and knowledge retention.

Guidance

G 5.6.3.4 If delayed acknowledgement of the AWS warning results in a brake demand,operating the AWS caution acknowledgement button acknowledges the AWS audiblewarning and the AWS brake demand indication.

RSSB Page 81 of 133

5.6.4 AWS brake demand indication functions

5.6.4.1 The AWS brake demand indication shall flash when an AWS brake demand isinitiated.

5.6.4.2 The AWS brake demand indication shall change from lit flashing to lit steady whenthe AWS caution acknowledgement control is operated.

Rationale

G 5.6.4.3 Interpretability: The train driver uses the lit flashing indication to confirm that thebrake demand is caused by an AWS intervention, and uses the lit steady indication toconfirm that the brake demand has been acknowledged.

Guidance

G 5.6.4.4 The brake demand is activated following an AWS warning that has not beenacknowledged within the AWS caution acknowledgement delay period.

G 5.6.4.5 After acknowledgement, the AWS brake demand indication remains lit to remind thetrain driver of the cause of the brake demand.

5.6.5 SPAD brake demand indication functions

5.6.5.1 The SPAD brake demand indication shall flash when the TPWS aerial at the front ofthe train passes over an active TSS loop and a brake demand is initiated.

5.6.5.2 The SPAD brake demand indication shall change from lit flashing to lit steady whenthe SPAD brake demand acknowledgement control is pressed and released.

Rationale

G 5.6.5.3 Train driver learning: Consistent functionality supports train driver learning andknowledge retention.

G 5.6.5.4 Interpretability: The train driver uses the lit flashing indication to confirm that thebrake demand results from a SPAD intervention and uses the lit steady indication toconfirm that the brake demand has been acknowledged.

Guidance

G 5.6.5.5 A SPAD brake demand is acknowledged when the SPAD brake demandacknowledgement control is pressed and released.

G 5.6.5.6 After acknowledgement, the SPAD brake demand indication remains lit to remind thetrain driver of the cause of the brake demand.

5.6.6 Overspeed brake demand indication functions

5.6.6.1 The overspeed brake demand indication shall flash when the TPWS aerial at the frontof the train passes over an active OSS loop and a brake demand is initiated.

5.6.6.2 The overspeed brake demand indication shall change from lit flashing to lit steadywhen the overspeed brake demand acknowledgement control is operated.

of 133 RSSB

Rationale

G 5.6.6.3 Train driver learning: Consistent functionality supports train driver learning andknowledge retention.

G 5.6.6.4 Interpretability: The train driver uses the lit flashing indication to confirm that thebrake demand results from an overspeed intervention and uses the lit steadyindication to confirm that the brake demand has been acknowledged.

Guidance

G 5.6.6.5 An overspeed brake demand is acknowledged by pressing and releasing theoverspeed brake demand acknowledgement control.

G 5.6.6.6 After acknowledgement, the overspeed brake demand indication remains lit toremind the train driver of the cause of the brake demand.

5.6.7 AWS/TPWS brake demand indication combinations and transitions

5.6.7.1 When the AWS/TPWS is providing the train protection function, the three AWS/TPWSDMI brake demand indications shall conform with the combinations and transitionsshown in Figure 4.

RSSB Page 83 of 133

Figure 4: AWS/TPWS brake demand indication combination and transitions

of 133 RSSB

Rationale

G 5.6.7.2 Interpretability: Displaying consistent sequences of indications supports correctinterpretation, and train driver learning and knowledge retention.

Guidance

G 5.6.7.3 The indication sequences and transitions shown in Figure 4 are consistent with thetrain driving rules and procedures applicable to AWS/TPWS operations.

G 5.6.7.4 Figure 4 excludes the sequences of indications shown:

a) During the power-up test. Section 5.7 sets out the requirements for the sequenceof indications during the power-up test

b) When the AWS/TPWS is suppressed, in temporary override, or isolationc) When there is a fault. Section 5.8 sets out the requirements for fault indications.

5.6.8 AWS/TPWS DMI indication functions when the AWS/TPWS onboard subsystem issuppressed

5.6.8.1 When the AWS/TPWS onboard subsystem is suppressed:

a) AWS/TPWS fault indication functions shall remain active.b) All other AWS/TPWS lit indications shall be disabled or extinguished.

Rationale

G 5.6.8.2 Interpretability: When the train protection functionality is provided by anothersystem (for example ERTMS/ETCS), disabling or extinguishing irrelevant AWS/TPWSindications declutters the driving desk and reduces the likelihood of distraction.

G 5.6.8.3 Integration with train operations: The AWS/TPWS fault indication functionality ismaintained to enable the train driver to monitor the system state and takeappropriate action before the train reaches a location where TPWS is required to be inuse.

Guidance

G 5.6.8.4 Where an integrated DMI is provided, the facility to display Class B information onthe ERTMS/ETCS DMI might not be available when the train is operating in ETCSother than in Level NTC. In this case, an alternative method of indicating a fault maybe needed, for example, using the train management system.

5.6.9 SPAD brake demand indication functions: priority

5.6.9.1 When the TPWS onboard subsystem initiates a SPAD brake demand after it hasinitiated an OSS brake demand, the overspeed speech announcement shall beimmediately terminated and replaced by the SPAD speech announcement.

RSSB Page 85 of 133

Rationale

G 5.6.9.2 Safe integration: The SPAD speech announcement is presented without delaybecause the consequence of a SPAD is potentially more serious than an overspeedevent.

Guidance

5.6.10 TPWS brake demand indications: speech announcement functions

5.6.10.1 Only one TPWS brake demand speech announcement shall be played at a time.

5.6.10.2 Once activated, the SPAD brake demand speech announcement shall:

a) Play at least one complete cycle.b) Repeat the speech announcement, without the priming tone, with an interval of

3 s between the end of one announcement and the beginning of the nextannouncement until the SPAD brake demand acknowledgement control isoperated.

5.6.10.3 Once activated, the overspeed brake demand speech announcement shall:

a) Play at least one complete cycle, unless the SPAD brake demand function isactivated.

b) Unless terminated by the SPAD brake demand function, repeat the speechannouncement, without the priming tone, with an interval of 3 s between the endof one announcement and the beginning of the next announcement until theoverspeed brake demand acknowledgement control is operated.

Rationale

G 5.6.10.4 Interpretability: Continued and clear presentation of the speech announcementreinforces the train driver's understanding of the cause of the brake demand. Thecomplete announcement is played to control the likelihood of a train drivermisinterpreting the indication.

Guidance

G 5.6.10.5 Table 14 sets out the requirements for the content of the TPWS brake demandaudible indications.

5.6.11 Independence of AWS audible indications and TPWS audible indications

5.6.11.1 TPWS audible indications shall not delay or prevent the operation of the AWS audibleindications.

Rationale

G 5.6.11.2 Interpretability: AWS audible indications are related to the signal or sign that thetrain is approaching, and they are sounded without delay so that the signal or sign iswithin the train driver's view when the indication sounds.

of 133 RSSB

Guidance

G 5.6.11.3 The AWS and TPWS provide separate, complementary contributions to trainprotection functionality. AWS indications are provided to draw the train driver’sattention to signal aspects and warning signs to reduce the likelihood of an unwantedevent. The TPWS indications are provided to inform the train driver’s response to abrake demand to reduce the consequences of an unwanted event.

G 5.6.11.4 The AWS and TPWS audible indications are distinctly different so that a train drivercan detect whether one or the other are sounding, or both are sounding at the sametime.

G 5.6.11.5 Table 14 sets out the requirements for the AWS and TPWS audible indications.

5.6.12 TPWS temporary isolation indication functions

5.6.12.1 The temporary isolation indication shall be lit when the TPWS temporary isolationfunction is enabled.

Rationale

G 5.6.12.2 Interpretability: The lit steady indication is used by the train driver to understand thatthe TPWS onboard subsystem has been temporarily isolated and that the rules foroperating the train without TPWS protection are applicable.

Guidance

G 5.6.12.3 Further requirements for the TPWS temporary isolation indication are set out in Table18.

5.6.13 AWS/TPWS fault indication functions

5.6.13.1 The relevant fault indication shall be lit flashing when either of the followingconditions are met:

a) An AWS onboard subsystem fault is detected.b) A TPWS onboard subsystem fault is detected.

Rationale

G 5.6.13.2 Interpretability: The lit flashing indication is used by the train driver to understandthat the AWS or TPWS function has a fault and that the rules for operating the trainwith defective AWS or TPWS equipment are applicable.

Guidance

G 5.6.13.3 This requirement is applicable to AWS/TPWS onboard subsystem faults that ariseduring the power-up test and faults that arise when the train is operating.

G 5.6.13.4 The AWS/TPWS fault indications can be presented by the indicator that also presentsthe TPWS temporary isolation indication.

RSSB Page 87 of 133

G 5.6.13.5 Any TPWS temporary isolation function is automatically cancelled at power-up;therefore, the indicator will be extinguished at the end of the power-up test unless anAWS/TPWS onboard subsystem fault has been detected.

G 5.6.13.6 Section 4.2.3.4 sets out further requirements for detection of TPWS onboardsubsystem faults.

5.6.14 TPWS train stop override indication functions

5.6.14.1 The train stop override indication shall be presented (lit) when the TPWS train stopoverride function is active.

5.6.14.2 The train stop override indication shall be unlit following a power-up test and remainunlit until the train stop override function is activated.

Rationale

G 5.6.14.3 Interpretability: The train stop override indication is used by the train driver tounderstand that the TPWS train stop override function is effective and the rules forpassing a signal at danger are being applied.

Guidance

G 5.6.14.4 When the train stop override times out, the indication is extinguished.

G 5.6.14.5 Further requirements for the train stop override function are set out in 5.5.3.

5.7 AWS/TPWS onboard subsystem power-up test functions

5.7.1 Power-up test sequence

5.7.1.1 The AWS/TPWS onboard subsystem power-up test shall incorporate the followingsequence of indications and control operations:

a) All the indicators that display the indications set out in Table 13 shall besimultaneously lit and then simultaneously extinguished within 0.5 s of the power-up test commencing.

b) The AWS warning audible indication (horn) shall sound.c) When the AWS caution acknowledgement control button is pressed and released:

the AWS warning audible indication (horn) shall stop, the AWS clear indication(bell) shall sound for 0.5 (+ 0.5/-0) s, and the AWS warning acknowledgementvisual indication (sunflower) shall be presented.

5.7.1.2 If, during the power-up test sequence, the AWS warning is not acknowledged, theAWS audible warning shall continue to sound for 30 s and the AWS/TPWS faultindication shall then be presented.

Rationale

G 5.7.1.3 Safe integration: The power-up test allows the train driver to confirm that the AWS/TPWS indications and the AWS warning acknowledgement button are operatingcorrectly, before the train is operated.

of 133 RSSB

G 5.7.1.4 Reliability and availability: The AWS horn is silenced after 30 s if noacknowledgement has been received, as there might be a fault condition whichprevents an acknowledgement being given. This allows the power-up test to continuewithout unnecessary disturbance to the train driver.

G 5.7.1.5 Interpretability: The power-up test provides the train driver with the followingopportunities to identify a fault:

a) A lit fault indication.b) A failure of the AWS caution acknowledgement control.

G 5.7.1.6 Integration with train operations: A consistent power-up test sequence supports traindriver learning and knowledge retention. Extinguishing all the brake demandindicators means that when there is a lit brake demand indication, it is caused by aTPWS brake intervention.

Guidance

5.7.2 Power-up test: Brake demand function

5.7.2.1 The AWS/TPWS power-up test shall initiate a brake demand.

5.7.2.2 If the power-up test identifies an AWS/TPWS onboard subsystem fault, the brakedemand shall be sustained until both of the following conditions are met:

a) Any AWS/TPWS onboard subsystem faults have been clearedb) An AWS/TPWS power-up test has been successfully completed.

Rationale

G 5.7.2.3 Reliability and availability: The brake demand function is tested to confirm that theAWS/TPWS onboard system will be capable of initiating a train brake applicationwhen this is necessary.

G 5.7.2.4 Safe integration: If the brake demand function is defective, the train brake issustained to prevent the train from being operated without effective train protectionfunctionality.

Guidance

G 5.7.2.5 If the power-up test fails because the AWS caution acknowledgement button is notoperated correctly, the power-up test can be restarted.

G 5.7.2.6 If the power-up test fails and the train brake demand is sustained, the AWS/TPWSonboard system may need to be isolated to move the train.

5.7.3 Indication of successful completion of AWS/TPWS power-up test

5.7.3.1 Successful completion of the power-up test shall be indicated by the speech message:‘TPWS and AWS operational’.

5.7.3.2 The speech message shall not be preceded by a priming tone.

RSSB Page 89 of 133

Rationale

G 5.7.3.3 Reliability and availability: Using a speech message to confirm successful completionof the power-up test allows the train driver to confirm that the speech messagefunction is working correctly before the train is operated.

G 5.7.3.4 Safe integration: The speech message capability is an essential component of theSPAD and overspeed audible indications that support the train driver in applying thecorrect procedures in response to a TPWS brake demand.

G 5.7.3.5 Interpretability: The priming tone is omitted because there is no need to draw thetrain driver's attention to the power-up test taking place.

Guidance

G 5.7.3.6 The speech message ‘TPWS and AWS operational’ can be found in the sound file onthe RSSB website at https://www.rssb.co.uk/Library/standards-and-the-rail-industry/sound-files/tpws-aws.wav.

G 5.7.3.7 When the power-up test is successfully completed, all the brake demand indicationsare extinguished.

5.7.4 Reactivation of previous brake demand following AWS/TPWS power-up test

5.7.4.1 If the cab is powered down when a brake demand indication is displayed; when thecab is powered up again, and the power up test is complete:

a) The train brakes shall remain applied.b) The same brake demand visual indicator(s) previously lit shall present a lit steady

indication.c) The audible brake demand indications shall not sound.

Rationale

G 5.7.4.2 Safe integration: This prevents a brake demand from being overridden by poweringthe cab down and powering it up again.

G 5.7.4.3 Interpretability: The visual indication is provided to remind the train driver that theAWS/TPWS caused the brake demand, and that the rules for acknowledging andreleasing the brakes apply.

Guidance

G 5.7.4.4 If no brake demand is applicable, all the brake demand/acknowledgement indicationsare extinguished after the power-up test.

5.8 AWS/TPWS fault indications

5.8.1 Indication of faults detected during the AWS/TPWS power-up test

5.8.1.1 The AWS/TPWS DMI shall display the following when the AWS/TPWS power-up testdetects a fault:

a) The fault indication shall be lit flashing.

of 133 RSSB

b) All other indications shall be extinguished.

Rationale

G 5.8.1.2 Integration with train operations: When the system has failed to power-up correctly,all other AWS/TPWS indications are irrelevant. If there is a fault, displaying otherindications might mislead the train driver into taking an incorrect action.

Guidance

5.8.2 Indication of loss of AWS/TPWS protection

5.8.2.1 The AWS/TPWS DMI shall display the fault indication when there is a loss of theprotection provided by the TPWS.

5.8.2.2 The fault indication shall continue to be displayed until any of the following applies:

a) The fault has been rectified so that the TPWS protection is restored.b) The AWS/TPWS activates a brake demand.c) The TPWS temporary isolation function is activated.

Rationale

G 5.8.2.3 Interpretability: The flashing fault indication is used to draw the train driver'sattention to the TPWS fault and inform an understanding that the operational rulesfor operating the train without TPWS protection are applicable.

Guidance

5.8.3 Suppression of AWS/TPWS fault indications

5.8.3.1 The AWS/TPWS fault indication shall be temporarily suppressed when either of thefollowing conditions apply:

a) An AWS/TPWS brake demand indication is displayed.b) The TPWS temporary override function is active, and the same indicator is used to

display the TPWS fault indication and the TPWS temporary isolation indication.

5.8.3.2 The AWS/TPWS fault indication shall be unsuppressed when the brake demand isreleased or the temporary isolation is removed.

Rationale

G 5.8.3.3 Interpretability: The fault indication is suppressed while the brake demand is active tocontrol the likelihood of the flashing fault indication distracting the train driver fromthe brake demand indication.

G 5.8.3.4 Integration with train operations: Indicating a temporary isolation is more importantthan indicating a fault, as the isolation removes all protection provided by TPWS,while in the case of a fault some protection may still be provided.

RSSB Page 91 of 133

Guidance

G 5.8.3.5 If the train, despite the indicated fault, is still able to correctly initiate a SPAD oroverspeed brake demand, this is indicated to the driver in the normal way by aflashing brake demand indication.

G 5.8.3.6 Where a combined indicator is used for temporary isolation and faults, temporaryisolation of the system overrides the (flashing) fault indication, as it uses the sameindicator illuminated steadily.

G 5.8.3.7 The fault indication is extinguished when the fault is no longer present.

of 133 RSSB

Part 6 System Availability and Integrity

6.1 Availability and integrity of the AWS/TPWS system

6.1.1 AWS and TPWS equipment shall be designed, operated and maintained to have alevel of availability that is as high as reasonably practicable, and shall, as a minimum,meet the following:

a) The trainborne subsystem shall have an availability, measured on a ‘per fleet, peryear’ basis, of not less than 99.9%.

b) The AWS track subsystem shall have an availability, measured on an ‘AWSpopulation, per year’ basis, of not less than 99.9%.

c) The TPWS track subsystem shall have an availability, measured on a ‘TPWSpopulation, per year’ basis, of not less than 99.9%.

Rationale

G 6.1.2 To meet the shared responsibility for safe operation, both elements of the system –the trainborne subsystem and the track subsystem – for both AWS and TPWS aredesigned to the meet specified availability levels in order to provide an appropriatelevel of confidence in the availability of the overall system.

Guidance

G 6.1.3 No guidance.

RSSB Page 93 of 133

Appendices

Appendix A AWS/TPWS DMI System Models

Figure 5: AWS/TPWS DMI structural viewpoint

of 133 RSSB

Figure 6: Train driver operational context viewpoint: AWS DMI use cases

RSSB Page 95 of 133

Figure 7: Train driver operational context viewpoint: TPWS DMI use cases

of 133 RSSB

Appendix B AWS/TPWS Control and Indication Panel

B.1 Guidance on AWS/TPWS DMI panel configuration

Figure 8: AWS/TPWS panel layout

Figure 9: AWS/TPWS panel dimensions

B.1.1 Figures 8 and 9 set out the configuration of the AWS/TPWS control and indicationpanel that forms part of the DMI applied to rail vehicles that operate on the GBmainline railway.

B.1.2 This configuration, including the layout and labelling, is compliant with theparameters set out in this standard and is available when applying the CSM RA riskacceptance principle: Comparison with a similar reference system and assessment.

B.1.3 Modification to this configuration would involve a risk assessment to confirm that thechange is acceptable.

RSSB Page 97 of 133

Appendix C AWS/TPWS DMI VDU layouts

C.1 AWS/TPWS DMI Example Layouts for VDU Solutions

Figure 10: Example layout for touch screen VDU

Figure 11: Example layout for soft key VDU

C.1.1 The screen layouts above are taken from RSSB research report T1079, 'Coexistentoperation of ERTMS and Class B (AWS and TPWS) systems: the development and usertesting of an integrated DMI'.

of 133 RSSB

C.1.2 They are included as examples of the general layout of a VDU implementation of theAWS/TPWS DMI.

C.1.3 The example layout for a soft key VDU shows how duplicating an indication enablesthe AWS/TPWS indications to be grouped in a consistent way and also identifies theapplicable soft key.

RSSB Page 99 of 133

Appendix D Not used

of 133 RSSB

Appendix E Guidance on AWS Design Principles

E.1 Guidance on AWS design principles

Failure modes

E.1.1 AWS equipment (both track and train sub-systems) should be designed andinterfaced with other equipment and systems (including power supplies) so that, sofar as is reasonably practicable, there is no credible failure mode, as experienced bythe driver, which results in any of the following events:

a) A ‘clear’ audible indication being given to the driver when a ‘warning’ indicationshould have been given.

b) No indication being given when a ‘warning’ indication should have been given.c) A caution acknowledgement being effected – that is, the equipment entering the

restrictive acknowledgement state or the brake demand acknowledgement state(as set out in GERT8075) – that was not initiated by the driver operating thecaution acknowledgement device.

d) Failure to initiate an AWS brake demand when such a brake demand is required.e) Release of an AWS brake demand when not initiated by the driver.

E.1.2 Where it is not reasonably practicable to achieve this for any of the events set outabove, then the event should, so far as is reasonably practicable, be made self-protecting or self-revealing.

E.1.3 An AWS brake demand should be initiated automatically if the power supply to thetrainborne AWS equipment fails. Such an event should not, however, prevent thetrainborne equipment subsequently being isolated by the driver so that the train canbe moved.

Compatibility

E.1.4 Requirements for electromagnetic compatibility of railway equipment are set out inBS EN 50121.

E.1.5 AWS track equipment should not jeopardise the safe operation of neighbouringequipment as a result of the electromagnetic fields that it generates.

E.1.6 AWS track and trainborne equipment should be designed to withstandelectromagnetic fields emitted by other equipment that might otherwise jeopardisethe correct operation of the equipment.

E.1.7 AWS track and trainborne equipment should be sufficiently robust to withstand, andcontinue to operate correctly under, all reasonably foreseeable levels of mechanicalshock that might be experienced during normal railway operations.

E.1.8 The interfaces between the AWS track equipment and the signalling system shouldbe designed so as not to jeopardise the correct operation of either the AWS trackequipment or the signalling system.

E.1.9 The interfaces between the trainborne AWS equipment and other equipment andsystems on board the train should be designed so as not to jeopardise the correctoperation of either the trainborne AWS equipment or other equipment and systems.

RSSB Page 101 of 133

Appendix F Guidance on AWS Receiver Sensitivity Testing

F.1 Guidance on AWS receiver sensitivity testing

F.1.1 Trains entering service are required to have fully functional AWS equipment, inaccordance with GERT8075, in any cab that is intended to be used. In particular, AWSreceivers are required to meet the relevant sensitivity parameters set out inGERT8075.

F.1.2 Operation of AWS is monitored by the driver, who is required to report an AWS failurein accordance with the Rule Book, module TW5. If an incorrect indication is received,or no indication is received where one is expected, the driver should report it.However, many AWS magnets have an actual flux density higher than the minimumspecified level, and therefore correct operation of AWS may not confirm that thereceiver is sufficiently sensitive to detect magnets at the lower end of the specifiedflux range.

F.1.3 The AWS trainborne sub-system self-test routine, set out in 4.1.1, only tests thefunctionality and driver interface of the AWS train sub-system. It does not test theAWS receiver sensitivity.

F.1.4 Railway undertakings should establish procedures within their safety managementsystems to confirm that AWS receivers meet the sensitivity values set out inGERT8075.

F.1.5 The aim of the procedure is to provide assurance that trains will not operate with anon-compliant AWS receiver.

F.1.6 Where vehicles are fitted with both standard strength and extra strength AWSreceivers, the procedures should cover each type of AWS receiver.

F.1.7 Historically, a depot test magnet was the established method of testing AWS receiversensitivity, but it is permissible to use alternative methods to provide the requiredassurance.

F.1.8 Where provided, the test magnet should be positioned so that trains that need to betested pass over it before entering the main line network infrastructure.

F.1.9 A depot test magnet simulates an AWS track magnet using a south pole in order toinitiate an AWS warning indication in the cab.

F.1.10 Depot test magnets are required to produce lower flux density levels than other AWSmagnets in order to test the sensitivity of the AWS receiver and provide assurancethat the receiver is sufficiently sensitive to detect magnets at the lower end of thespecified flux range.

F.1.11 GERT8075 sets out the required flux density levels for depot test magnets forstandard strength and extra strength receivers respectively.

F.1.12 An extra strength AWS receiver (which is less sensitive than a standard receiver) maynot detect a standard strength depot test magnet, so an extra strength depot testmagnet is required to confirm its operation. However, detection of an extra strengthdepot test magnet does not adequately test the required sensitivity of a standardstrength AWS receiver.

of 133 RSSB

F.1.13 Depot test magnets only test the AWS receiver that is active when the train passesover the magnet. The AWS testing procedures should take account of circumstanceswhere there is potential for operation of trains in service using a different receiverthat has not been tested using the depot test magnet.

F.1.14 Examples of such circumstances include cases when:

a) A train reverses direction and a different receiver becomes active;b) A multiple unit train divides and another receiver becomes active;c) A switchable receiver is operated to an alternative sensitivity setting.

F.1.15 The process of AWS receiver testing should take account of:

a) The effectiveness of using depot test magnets and / or alternative methods todetect AWS receivers that do not comply with sensitivity requirements

b) The effectiveness of procedures in detecting AWS receivers that have beendamaged or displaced, and

c) The level of assurance of AWS receiver stability.

Appendix H Description of AWS and TPWS TrainborneEquipment

H.1 Description of AWS and TPWS trainborne equipment

Introduction

H.1.1 This section sets out an outline description of the components of the AWS and TPWStrainborne sub-system. As the functionality of AWS and TPWS is most often providedin a combined control unit, both AWS and TPWS equipment are described together toenable an understanding of the most commonly installed configurations. However,either system (AWS or TPWS) can be applied on its own and, in some cases, forexample certain shunting locomotives, only TPWS has been implemented.

H.1.2 AWS and TPWS components are supplied by a number of different manufacturers,and there are no mandatory technical specifications for the interfaces betweenindividual components creating a manufacturers’ trainborne sub-system. Therefore,there are no guarantees that a component supplied by one manufacturer iscompatible, under all foreseeable conditions, with a similar component from anothermanufacturer, unless this is declared by the manufacturers.

Trainborne sub-system components

H.1.3 Figure 12 shows a typical trainborne sub-system, including both AWS and TPWS usinga combined AWS and TPWS electronic control unit.

of 133 RSSB

Figure 12: Typical AWS/TPWS trainborne sub-system

H.1.4 The boxes shown dotted in Figure 12 are only necessary for a dual-cab single controlunit configuration, such as on a locomotive.

Combined electronic control unit

H.1.5 The combined AWS and TPWS control unit performs the logical functions, receivingvarious inputs and driving the external control and indication equipment. Mostcontrol units now in use are electronic, replacing the earlier relay logic types.

H.1.6 The control unit may also provide specific outputs to reset the vigilance system(where a multi-resettable vigilance device is used) and outputs to train data recordersto enable recording of the detection of track magnets, together with the response ofthe trainborne sub-systems.

AWS receiver

H.1.7 The AWS receiver detects the presence of the south and north poles from the track-mounted magnets and provides a signal to the control unit that one or both of themagnets have been detected. Several different types of receiver exist (although notall types may still be in use), including pivoted permanent magnet, standard and highstrength bi-stable reed relay type, twin lightweight bi-stable reed relay, andelectronic / solid state.

H.1.8 Some traction units may be fitted with two AWS receivers: one to detect standardstrength track magnets and one to detect extra strength track magnets (the twinlightweight reed receiver and electronic versions are designed to detect either magnettype within a single housing). Where both receiver types are fitted on a dual systemelectric traction unit, the vehicle control circuitry is arranged to select the correctreceiver depending on the traction current collection system in use. Diesel tractionunits generally use only a standard strength receiver, even if they also operate overlines fitted with extra strength track magnets.

H.1.9 Locomotives and other dual-cab vehicles are normally only fitted with one receiverand control unit which feed indications in either cab, as shown in Figure 12.

H.1.10 The receiver is mounted underneath the driving vehicle, either on the bogie orsuspended from the vehicle underside, nominally on the centre line of the vehicle, andwithin a height range that keeps the equipment both within kinematic gauge andable to respond to the minimum track magnet field strength specified in GERT8075under all dynamic conditions. The receiver cable is connected to a junction box whichforms a coupling and test point.

AWS alarm and indicator unit

H.1.11 The AWS alarm and indicator unit provides the main interface with the driver for AWSindications. The unit contains an electronic tone generator for the ‘caution’(approximately 800 Hz continuous tone) and ‘clear’ (approximately 1200 Hz chimetones), and contains the yellow / black visual indicator (also known as the sunflowerindicator) to remind the driver of the previous signal aspect and actions taken. Theunit is mounted in a position where the driver may readily see it from the normaldriving position. Several versions of this equipment exist, including those with amechanical sunflower and those with LED arrays to provide the yellow element of thesunflower.

H.1.12 Older installations may have separate audible (bell and horn) and visual (sunflower)indicators. These generally have conventional electric trembler bells, which ring for0.5 s for a clear signal, and pneumatic horns, although the horn may be of the‘Yodalarm’ electric type.

H.1.13 Where provided separately, the visual ‘sunflower’ indicator is normally of amechanical type and is larger than the combined alarm and indicator unit type. Itcontains a bi-stable electromechanical device with a magnetic circuit incorporatingtwo coils, and is magnetically latched in either of its two positions. Luminous paint isapplied to the yellow segments, so that the ‘black and yellow’ indication can be seenin the dark.

of 133 RSSB

TPWS aerial

H.1.14 The TPWS aerial receives the six TPWS frequencies transmitted from the track-mounted transmitter loops as set out in GERT8075. The aerial, in conjunction with thecontrol unit, may be capable of undertaking an integrity test as part of its inbuilt self-testing routines.

H.1.15 The aerial is mounted underneath the leading vehicle (either on the bogie orsuspended from the vehicle underside) nominally on the centre line of the vehicle,and within a height range that keeps the aerial both within kinematic gauge and ableto respond to the minimum track transmitter loop field strength specified inGERT8075 under all dynamic conditions.

H.1.16 For dual-cab vehicles, for example locomotives, two TPWS aerials are required, one ateach end, to prevent an unwarranted TPWS brake application due to detection ofsignal ‘self-reversion’. Self-reversion is the result of the signal returning to danger (redaspect) due to the passage of the train, which will cause the transmitter loop tobecome active. If the TPWS aerial has not passed clear of the transmitter loops at thesignal when they become active, then the brakes would be applied by TPWS as anunwarranted application. Self-reversion could also occur on a single-cab vehicle if theaerial is mounted more than 2.3 m behind the leading wheelset.

Driver’s control panel or DMI

H.1.17 The driver’s TPWS control panel (also known as the driver’s display unit or driver’sdisplay panel) or driver / machine interface (DMI) consists of TPWS status indicatorsand a Train Stop Override (TSO) pushbutton.

H.1.18 Older equipment incorporates a single brake demand indicator which indicates one ofthree TPWS brake demand states:

a) Unlit – no demand requested.b) Flashing – TPWS fault detected.c) Steady – TPWS temporarily isolated.

H.1.19 Newer types of display equipment incorporate three separate brake demandindicators, as set out in 5.4 and Appendix B.1: one for brake applications initiated byTPWS TSS (coloured red), one for brake applications initiated by TPWS OSS (colouredyellow) and one for an AWS brake application (also coloured yellow). Each of theseindicators will show one of the three brake demand states, as set out above.

H.1.20 The driver’s control panel / DMI also contains indications of TPWS temporaryisolation and faults, which are usually combined in a single indicator. A combinedtemporary isolation / fault indicator indicates three states:

a) Unlit – TPWS operational.b) Flashing – TPWS fault detected.c) Steady – TPWS temporarily isolated.

H.1.21 The TSO control is operated by the driver when it is necessary to pass a signal atdanger with the authority of the signaller. In this case, the TSS on the track will still betransmitting and hence the train would be tripped on a legitimate movement pastthe stop signal. However, the driver can operate the TSO, which will prevent a brake

demand from the first TSS the system encounters within a time period. The timeperiod is preset to 20 s for a passenger train or 60 s for a freight train. After the timeperiod, or on detecting the first TSS, the TSO will be reset to normal. When the TSOfunction is in operation, the TSO pushbutton (or associated indication) illuminatessteady yellow.

AWS reset pushbutton / TPWS acknowledgement

H.1.22 The AWS reset pushbutton (sometimes referred to as the AWS acknowledgementpushbutton) is also part of the driver’s interface and is mounted on, or built into, thedriver’s desk such that it can be readily operated from the driving position. Thepushbutton contains a changeover contact which allows the AWS receiver to reset,the audible indication to be silenced and the visual indication to be set to ‘yellow /black’.

H.1.23 On older systems, the AWS reset pushbutton is also used to acknowledge a TPWSbrake demand. When pressed after a TPWS brake demand, the control unit receivesan acknowledge input which will enable the release of the TPWS brake demand incombination with a preset timer.

H.1.24 On newer systems equipped with three brake demand indicators (compliant withGERT8030 issue three or later standards), a brake demand is acknowledged bypressing the appropriate push button associated with the brake demand indicationwhich has been activated.

Full isolation switch and indicator

H.1.25 A full isolation switch is provided for the driver to isolate the AWS and TPWStrainborne sub-system in the case of faults where:

a) The brakes will not release, orb) The AWS audible indications will not silence, orc) A succession of incorrect or spurious responses are given by the AWS or TPWS

systems.

H.1.26 Various types of isolation switch exist: older types may be retained in the normalposition with a seal or locking wire to deter abuse, while more modern installationsare arranged such that the switch once operated cannot be reset by the driver. Onolder locomotives the full isolation switch may be incorporated with the change endswitch.

H.1.27 Full isolation of AWS will also render the TPWS system isolated (and vice versa) as thecontrol unit also includes TPWS functionality. A TPWS temporary isolation switch isprovided to overcome this limitation when only TPWS may be at fault.

H.1.28 Full isolation is required to be indicated to the driver by a discrete indication or as partof a general safety system isolation indication. This is achieved on older vehicles bythe visible position of the isolation switch and on modern vehicles by an illuminatedindicator. The full isolation switch is required to:

a) Ensure that the power supply is isolated from the AWS trainborne sub-system.b) Ensure that no AWS or TPWS brake demand is or can be actioned.c) Ensure that all indications except the isolation status indicator are inoperative.

of 133 RSSB

d) Provide a clearly visible indication that enables a trainborne sub-system isolationto be detected in all relevant driving positions.

e) Provide an output to the train’s data recorder, where fitted, to indicate that thecomplete system is isolated.

TPWS temporary isolation switch

H.1.29 A TPWS temporary isolation switch is provided to allow the TPWS to overcome a faultin the sub-system which does not affect the AWS functions, for example a faultyTPWS antenna.

H.1.30 The switch is centre-biased to the ‘off’ position so that when the equipment ispowered down and on again, any existing temporary isolation will be removed.

H.1.31 The switch is mounted out of reach from the normal driving position.

H.1.32 On some dual-cab vehicles only one temporary isolation switch is provided.

AWS isolation switch

H.1.33 On newer vehicles a separate AWS isolation switch may be provided to allow isolationof the AWS functions in case of a failure, for example one which prevents release ofan AWS brake application, while allowing the TPWS to continue in operation.

H.1.34 On older vehicles there is no facility to isolate the AWS separately from the TPWS.

Appendix J AWS and TPWS Trainborne Equipment - Fault andFailure Management

Note: AWS Fault Codes are defined in RIS-0707-CCS.

J.1 Process for investigating right side AWS and TPWS trainborne equipment failures

J.1.1 The process shown in Figure 13 is recommended to reduce the incidence oftrainborne equipment being identified as faulty following a failure report when thefailure was actually due to external influences. This will help to reduce cases wherethe equipment is sent for investigation but no fault is found. This process makes useof new technologies that have been produced for fault diagnosis.

J.1.2 Various equipment exists to conduct a full AWS and / or TPWS test. A simple AWSfunctional test can be carried out using a hand-held magnet, as set out in Appendix K.Other test equipment should be used in accordance with the manufacturer’sinstructions.

J.1.3 Depot test procedures, as laid down in vehicle maintenance instructions, should befollowed. If any item is identified as the cause of the fault, then it should be removed,sent for repair and a new item refitted. If the reported fault can be repeated, butchanging the suspected faulty item does not cure the fault, then the fault is likely tobe caused either by another faulty item of equipment, or the vehicle wiring. If thevehicle wiring is suspected to be faulty, it may need to be continuity and insulationtested if no obvious faults can be identified.

J.1.4 After removing and / or changing any equipment, a full AWS and / or TPWS testshould be conducted before releasing vehicles back into service.

of 133 RSSB

Figure 13: AWS/TPWS right side failure investigation process

J.2 Process for investigating wrong side AWS and TPWS trainborne equipmentfailures

J.2.1 The process shown in Figure 14 is recommended to reduce the incidence of wronglydiagnosed faulty equipment due to external influences, and in light of the newtechnologies that have been produced for fault diagnosis. This process relies on theuse of approved test equipment such as the STS / Mors Smitt TY287 AWS tester.

J.2.2 The AWS control unit and receivers are often sent to an approved technicalinvestigation centre following a reported AWS code 5 or 7 failure, as the equipment isoften assumed to have suffered a wrong side failure. However, in many cases thetechnical investigation centres are unable to find any faults with the equipmentunder investigation. In some cases, reported AWS code 5 or 7 failures have beencaused by the trackside AWS equipment or by traincrew errors.

J.2.3 Similarly for TPWS, alleged wrong side failures may be due to track-mountedequipment faults, driver error or operational circumstances, as identified in thecommon causes sections.

J.2.4 TDR data should be downloaded at the earliest opportunity by maintenance depotstaff, to avoid it being overwritten or otherwise lost. TDR data should be supplied tothe technical investigation centre to aid its investigation. This evidence may assistexperts to pinpoint the cause of the failure, which may lie in the train wiring orancillary components such as the AWS acknowledgement pushbutton. Technicalinvestigation centres may in turn seek advice from the relevant AWS/TPWSsupplier(s).

of 133 RSSB

Figure 14: AWS wrong side failure investigation process

J.3 Managing defective AWS and TPWS trainborne components

J.3.1 Defective AWS and TPWS components should be managed in accordance with theRU’s quality procedures, in order that defective components are segregated, labelled,and despatched for repair or scrap, as appropriate.

J.3.2 For example, faulty items of AWS and TPWS equipment which have been involved ina right side failure should be treated as follows:

a) The equipment should be adequately packed, using special packaging, whereavailable, and be clearly labelled as 'AWS/TPWS equipment for repair'.

b) Equipment changed as a result of a 'right side failure’ should be sent to theappropriate repair agent for repair.

J.3.3 Faulty items of AWS and TPWS equipment which have been involved in a wrong sidefailure should be treated as follows:

a) The equipment should be adequately packed, using special packaging, whereavailable, and have an appropriate label, generally coloured red, identifying theurgent nature of the package attached prior to dispatch. A wrong side failurereport form should also be enclosed in the package.

b) Equipment changed as a result of a wrong side failure should be sent for technicalinvestigation to an approved, competent technical investigation body. It isexpected that a competent technical investigation body will provide detailedfeedback to the RU on the nature of the defects found, as this may require furtheraction on behalf of the RU on its fleet and, in certain cases, ‘urgent’ advice beinggiven to other operators.

c) Equipment sent for technical investigation and / or repair should be properlylabelled and accompanied by sufficient information to enable the investigators orrepairers to properly diagnose and rectify faults. This information should includerelevant TDR data, which may be sent electronically. A copy of the TDR datashould be retained by the depot for possible future analysis that may be requiredfollowing investigation by the technical investigation body.

J.4 Fault-finding techniques for defective AWS and TPWS trainborne equipment

J.4.1 A traditional method of diagnosing AWS faults has been to use an AWS hand-heldtest magnet waved under the receiver to simulate the train passing over the AWStrack magnets and hence functionally test the system (see Appendix K). Functioningthe AWS system with a hand-held test magnet has the advantage of easily andquickly testing the AWS trainborne sub-system. Replacement of key components canbe undertaken to remedy the fault, having tracked down the likely faulty componentusing a systematic process, in part using test equipment. More sophisticated testequipment is now available to supplement the basic functional test, thus allowingfaults to be detected and healthy equipment to be identified more reliably.

J.4.2 For all fault-finding techniques, some basic checks should be undertaken first, asfollows:

a) Check the vehicle records and component tracker system, to determine whetherthe vehicle has been involved in any AWS related incident within the last 12months.

of 133 RSSB

b) Measure and record the height of the bottom of the AWS receiver above rail level.This should be within the limits applicable to the vehicle concerned (as specified inthe vehicle maintenance instruction). Standard electromechanical AWS receiversare commonly mounted within the range 133 mm to 171 mm above rail level, andthe recommended height range for Thales electronic AWS receivers is between165 mm and 185 mm above rail level. Receiver height should be adjusted, asnecessary, on vehicles where adjustment is provided.

Standard strength AWS receivers running over high-strength track magnets arecommonly set towards the upper end of the permitted height range to avoidspurious right side failures by detecting high magnetic fields generated by cross-track traction cables, but if they are set too high this can result in failure to detectnormal strength magnets and hence wrong side failures.

Further, the TY309 AWS characterisation tester may be used to adjust the genericreceiver height tolerance for particular vehicles.

c) Examine items of equipment for possible causes of intermittent fault, for exampleexternal damage, loose connectors or water ingress to connectors.

J.4.3 The fault diagnosis procedures should enable faulty equipment to be reliablydiagnosed. If a fault persists, for example two repeat failures in three months, butcannot be traced by functional testing or the use of the various test equipment, and afault to the vehicle frame (earth fault) is suspected, then wiring checks should becarried out to trace any possible wiring faults, as follows:

a) Visually examine, as far as is possible, all items of the AWS/TPWS trainborne sub-system carefully for possible causes of an intermittent fault, for example externaldamage, loose connectors, water ingress or defective wiring.

b) Disconnect wiring connectors from components likely to be affected by insulationtesting, for example:

i) The AWS receiver.ii) The TPWS aerial.iii) The AWS alarm and indicator units (if fitted) and bells(s) / Yodalarm / horn

(if fitted).iv) The AWS/TPWS control unit.v) The TPWS driver’s control panel / DMI.vi) The EP repeat relay (if fitted).vii) The EP valves (if fitted) and voltage converter (refer to relevant vehicle

instructions).viii) Train data recorder or similar equipment.ix) All electronic equipment on the vehicle (or interconnected vehicles) not

capable of withstanding the insulation test voltages likely to be applied.c) Using an insulation tester (500 V or 1000 V), check that the cable insulation

resistance between AWS/TPWS cables and all other cables running with them(refer to vehicle wiring diagrams) is not less than 10 MΩ (wire to wire and wire toearth).

d) Using an insulation tester, check that the cable insulation resistance between eachAWS/TPWS cable and the vehicle chassis is not less than 10 MΩ.

J.4.4 Further guidance on possible fault causes is given in J.5.

J.4.5 In addition, data from train data recorders and train management systems mayinclude data related to the operation and performance of both the AWS system andthe train control systems at the time of the fault. When fault finding, considerationshould be given to downloading and analysing the data to assist in fault finding.These systems may also directly log the nature of the fault depending on thecomplexity of the installation.

J.4.6 Data from a train data recorder may also enable determination of any driver errorsthat may have led to an unintended (spurious) automatic brake application by theAWS. For example, a reported spurious brake demand could be due to late operationof the AWS reset pushbutton, or holding down the AWS reset pushbutton before thesystem detects the track magnet south pole. The sequence and timing of theseactions could be identified from the train data recorder.

J.4.7 A reported AWS or TPWS trainborne fault could be the symptom of an infrastructurefault, although this may not always be apparent. For example, an AWS fault code 8(horn when no indication expected) could be due to the AWS receiver on the traindetecting a magnetic flux from a cross-track cable, possibly as a result of a cablefault.

J.4.8 Data from train management systems may also provide a precise location (forexample, Ordnance Survey Grid Reference) which can be forwarded to the IM toinvestigate.

J.5 Guide to possible AWS and TPWS trainborne equipment faults

J.5.1 A guide to possible causes and remedies for AWS/TPWS failures associated with acombined electronic AWS/TPWS control unit is given in Figures 15 and 16 below. Theflowchart in Figure 16 is based on the power-up and self-test routine, following asequence from power-up of the system through the equipment automatic self-testroutine. These flowcharts have been published for information purposes only and donot take precedence over approved vehicle maintenance and fault-findingprocedures.

J.5.2 Some TPWS systems have improved fault reporting that may be used to trace a fault.This can be used in conjunction with the TDR data to assist in finding the cause ofany fault.

of 133 RSSB

Note: Fault codes 12-15 are not relevant to this document

Figure 15: Combined AWS/TPWS fault finding guide

Figure 16: Combined AWS/TPWS system fault-finding flowchart

of 133 RSSB

J.6 Common AWS and TPWS failure mechanisms

J.6.1 Some common AWS and TPWS failure mechanisms are set out below. These arecategorised into human error, system faults and trainborne sub-system equipmentfaults.

Type of fault Category of fault Possible cause

AWS failed system power-up test

System fault A cab is opened up withthe AWS receiver directlyover an AWS magnet

Unwarranted AWS brakeapplication

Human error Driver not resetting AWSwithin the specifiedcaution acknowledgementperiod

AWS fault code 1 (hornand bell when clearindication expected)

Trainborne equipment Spurious switching of AWSreceiver – fault in AWSreceiver or cable

AWS fault code 2 (horninstead of bell when clearindication expected)

System fault Faulty track magnet (forexample electromagnetfault or field strength outof specification).

AWS receiver on the trainmarginal sensitivity ormounted too high orpassing over magnet atextreme of suspensionmovement

AWS fault code 2 (horninstead of bell when clearindication expected)

Trainborne equipment AWS receiver faults –check AWS receiver heightand sensitivity

AWS fault code 3 (noindication instead of bell)

Trainborne equipment AWS alarm and indicatorunit or bell fault

AWS fault code 4 (bell andhorn when warningindication expected)

Trainborne equipment Reed AWS receiversoperating over extrastrength magnets,particularly at slow speed,may give rise to AWS code4 failures as a result ofincorrect operation ofinternal relays within thereceiver. This fault couldbe masked in older relaybased logic units by thetiming of relay operation,but was revealed followingthe fitting of electroniccontrol units. A possiblesolution would be toreplace the reed AWSreceiver with an electronicsolid state AWS receiver

AWS fault code 5 (bellinstead of horn)

WRONG SIDE FAILURE

Trainborne equipment Permanent reset voltageon AWS receiver due toshort circuit on AWS resetpushbutton or faultycontrol unit

AWS fault code 5 (bellinstead of horn)

WRONG SIDE FAILURE

System fault False energisation of anAWS receiver byunintentional magneticflux – may be a particularissue for standard strengthreceivers operating overextra strength magnets

AWS fault code 6 (brakewithout horn)

Trainborne equipment AWS alarm and indicatorunit or horn fault

AWS fault code 7 (noindication or brake whenwarning indicationexpected)

WRONG SIDE FAILURE

System fault False energisation ofanAWS receiver byunintentional magneticflux – may be a particularissue for standard strengthreceivers operating overextra strength magnets

of 133 RSSB

AWS fault code 6 (brakewithout horn)

Trainborne equipment AWS alarm and indicatorunit or horn fault

WRONG SIDE FAILURE

System fault Faulty track magnet (forexample permanentmagnet field strength outof specification)

WRONG SIDE FAILURE

Trainborne equipment AWS receiver failed todetect track magnet –check AWS receiver heightand sensitivity

AWS fault code 8 (hornwhen no indicationexpected)

System fault Trainborne equipmentdetecting a strongmagnetic field from non-AWS tracksideinfrastructure, for examplehigh currents passingthrough cross-tracktraction cables

AWS fault code 8 (hornwhen no indicationexpected)

Trainborne equipment AWS receiver failure

AWS Fault Code 9 (bellwhen no indicationexpected)

System fault Trainborne equipmentdetecting a strongmagnetic field from non-AWS tracksideinfrastructure, for examplehigh currents passingthrough cross-tracktraction cables

AWS fault code 10 (unableto cancel)

Human error Driver holding down theAWS reset pushbuttonbefore the AWS cautionaudible tone is sounded

System fault A cab is opened up withthe AWS receiver directlyover an AWS magnet

Trainborne equipment Identified issue withThales Mark I control unitsprior to modificationstatus strike 4

AWS fault code 11(indicator not changing to‘all black’)

Trainborne equipment AWS alarm and indicatorunit or sunflower fault

TPWS failed systempower-up test

System fault A cab is opened up withthe TPWS aerial directlyover an active TPWStransmitter loop (affectsolder systems; newersystems may be able tocope with this situation)

TPWS fault code 16 (TPWSfailed to activate)

WRONG SIDE FAILURE

Trainborne equipment TPWS aerial not correctlylocated (possibly due tomovement of the aerialwithin the assembly) butelectrically still connectedto control unit – possiblesolution is to install acomposite aerial harnesswhich has a mechanicallocation

TPWS fault code 16 (TPWSfailed to activate)

WRONG SIDE FAILURE

System fault Faulty TPWS transmitterloop

TPWS fault code 17 (TPWSoperated when notrequired)

Human error Over-speeding on OSS forsignal or PSR

TPWS not temporarilyisolated when required

TPWS TSO not operated ortimed out before passingsignal at danger withauthority

of 133 RSSB

TPWS fault code 17 (TPWSactivated when notrequired)

System fault Thales Mark I modification0 control units couldgenerate a brake demanddue to trainborneequipment detecting avalid sequence of signalswhen travelling reversedirection over TSS

Trainborne equipmentdetecting TPWSfrequencies from tracksideinfrastructure, specificallythe harmonics of certainTI21 track circuittransmitters (higher risk ifTPWS aerial is ahead ofthe leading axle)

TPWS OSS still active formovement controlled bysubsidiary signal (standardarrangement is now tosuppress OSS whensubsidiary signal off)

TPWS ‘self-reversion’ dueto TPWS TSS reactivatedbefore TPWS aerial clearof transmitter loops

Trainborne equipmentwrongly interpreting OSStransmitter loop lobes asmain field at low speed(experienced as awidespread problem atterminal stations wherefull size OSS loops werefitted on approach tobuffer stops – generallyavoided by changing tominiature loops)

Failure of TDR to recordAWS/TPWS outputs

Trainborne equipment Failure of control unit TDRoutput relay volt-freecontacts soft-sticking dueto inrush current damage

AWS/TPWS brakeapplication delay

POSSIBLE CAUSE OFWRONG SIDE FAILURE

Trainborne equipment Thales control units priorto modification strike 2subject to internal brakedemand relay failure(sticking armature) –replace and return toThales

Flashing fault light ondriver’s control panel

Trainborne equipment Intermittent connectionproblem between TPWSaerial and connectingcable (solutions are toreplace the aerial/cableconnector arrangementwith a hard-wired aerial orimprove the securingmechanism for the aerial/cable interface). Check theaerial for continuity

Table 19: Common AWS/TPWS faults

Note: Fault codes 12-15 are not relevant to this document

of 133 RSSB

Appendix K AWS Testing using a Hand-Held Permanent Magnet

K.1 AWS testing using a hand-held permanent magnet

K.1.1 An AWS hand-held test magnet can be used, as set out in Table 20 below, to checkthe functioning of the AWS trainborne sub-system to detect where, within the basicsequence of events, a fault occurs. Testing the AWS trainborne sub-system with ahand-held test magnet has the advantage of rapidly repeating the failure. Dual-cabvehicles should be tested from both ends, as failure at one end only will indicate thatthe control unit, PSU and AWS receiver are healthy.

Test item Action

A1 Before any equipment or connections are disturbed, perform thetests set out in items A2 to A8.

A2 With the air system fully charged, energise the AWS in the cab inwhich the failure is reported to have occurred

A3 Check that the horn sounds. Press and release the 'AWSacknowledge' pushbutton to silence the horn

A4 Carry out a caution signal test cancelling the AWS as follows:

• Simulate a caution indication by passing the south pole (blue)end of the magnet under the AWS receiver.

• The indicator should change to or remain 'all black', and after1 s the horn should sound.

• Within 2 s, press and release the 'AWS acknowledge'pushbutton to silence the horn − the indicator should change to'yellow and black' and there should be no brake application.

A5 Carry out a caution signal test allowing a full brake application andthen cancel the AWS, as follows:

• The indicator should change to or remain 'all black', the hornshould sound after 1 s and, after a further time delay (2.0 s or2.7 s) appropriate to the vehicle concerned, a full brakeapplication should occur.

• Press and release the 'AWS acknowledge' pushbutton − thehorn should be silenced and the indicator should change to'yellow and black' and, after a time delay appropriate to thevehicle concerned, the brake should release at least 59 s afterthe brake application

Test item Action

A6 Carry out a caution signal test allowing a partial brake applicationand then cancel the AWS, as follows:

• The horn should sound after 1 s. As soon as the brake starts toapply, press and release the 'AWS acknowledge' pushbutton tosilence the horn − the brake should continue to apply andshould not release until after a time delay appropriate to thevehicle concerned

A7 Carry out a clear signal test as follows:

• Simulate a clear indication by passing the south pole (blue) endof the magnet under the AWS receiver and then passing thenorth pole (red) end of the magnet under the AWS receiver,taking less than 1 s between the two operations.

• The indicator should change to 'all black’ and the bell ring forapproximately 0.5 s (or a single chime is emitted on vehiclesfitted with an alarm and indicator unit)

A8 Carry out a test with the AWS equipment isolated, as follows:

• Isolate the AWS in the cab concerned.• Operate the AWS receiver with the south pole (blue) end and

then the north pole (red) end of the magnet, taking less than1 s between the two operations. Follow this by operating theAWS receiver with the south pole (blue) end only − there shouldbe no effect on the AWS equipment.

• De-isolate the AWS in the cab concerned

A9 If any item of AWS equipment is suspected of being faulty itshould be changed. After the replacement has been fitted repeatitems A4 to A8 three times, if either:

• The reported fault can be reproduced, but changing the itemindicated during the above tests does not cure it, or

• The fault cannot be reproduced but the vehicle has a history ofrelated faults.

Check the system using an AWS test unit, if available, then visuallyexamine the wiring and connectors as far as reasonablypracticable. If the fault is still not revealed, then detailed wiringtests should be carried out

of 133 RSSB

Test item Action

A10 After any equipment change, wiring repair or renewal has beencarried out, items A4 to A8 should be repeated

Table 20: Test after a 'right side failure’ reported

K.1.2 An AWS hand-held test magnet can be used, as set out in Table 21 below, to checkthe functioning of the AWS trainborne sub-system as part of a wrong side failureinvestigation before any equipment / connections are disturbed. This should be aspart of an overall inspection and test procedure using more sophisticated AWS testequipment.

Test item Action

B1 Carry out items A2 to A8, repeating items A4 to A8 a total of threetimes

B2 If any item of AWS equipment is suspected of being faulty itshould be changed. If the AWS operates correctly or does notreproduce the reported fault, then follow procedures for a fullsystem test. After replacements have been fitted, items A2 to A8should be repeated, if either:

• The reported fault can be reproduced, but changing the itemindicated during the above tests does not cure it, or

• The fault cannot be reproduced but the vehicle has a history ofrelated faults.

Check the system using an AWS test unit, then visually examinethe wiring and connectors as far as reasonably practicable. If thefault is still not revealed, then detailed wiring tests should becarried out

B3 After any equipment change, wiring repair or renewal has beencarried out, items A4 to A8 should be repeated

Table 21: Test after a 'wrong side failure’ reported

Appendix L Guidance on AWS Route Compatibility Assessments

L.1 Guidance on AWS route compatibility assessments

L.1.1 If on a route it is proposed to replace AWS track equipment of one type (standard orextra strength) by equipment of the other type, the IM assesses the risks of so doing,taking into account the types of AWS receivers fitted to trains that operate on theroute. Trainborne AWS receivers are required to be compatible with the AWS trackequipment on the routes over which they operate, therefore changing the type ofmagnet may introduce incompatibility with existing receivers.

L.1.2 In some cases, non-standard arrangements of AWS equipment have been introducedto deal with particular situations. In such cases, changing the type of magnet (even ifthis change is from an existing non-compliant arrangement to a compliantarrangement) may introduce incompatibility with trainborne receivers which worksatisfactorily with the existing track equipment.

L.1.3 Where route compatibility is being assessed, as set out in RIS-8270-RST, the AWSreceiver arrangements on a train are assessed to determine whether they arecompatible with the type of AWS track equipment on the route over which the train isto operate. This is particularly relevant where a single sensitivity receiver is to beoperated over both standard strength and extra strength track equipment.

L.1.4 Where it is necessary for a train not fitted with AWS equipment to operate over anAWS fitted line, except where an alternative train protection system providing a levelof protection equivalent to or better than that provided by AWS and TPWS is fittedand in use on both the trains and the infrastructure, the IM and RU agree, documentand implement appropriate operating procedures to enable the safe movement oftrains. Agreed operational procedures are used to manage the risks arising from theoperation of trains not fitted with AWS on a line where AWS is provided as a primarysafety system.

of 133 RSSB

Definitions

Arming frequency

A frequency generated by the TPWS track sub-system which, when detected by the vehicle, armsthe train sub-system.

Automatic Warning System.

Availability

The ability of an item to be in a state to perform a required function under given conditions at agiven instant of time or over a given time interval, assuming that the required external resourcesare present. (Source BS EN 50129:2003.)

DC electrified lines

Lines equipped with DC electrification, whether or not the line is also equipped with ACelectrification.

Driver machine interface (DMI)

The driver machine interface provides indications to the driver of the system status, as well asallowing the driver to control selected system functions. The AWS/TPWS DMI includes controlsand indications which are grouped together and incorporated in a panel or VDU display as well asother controls and indications relating to AWS and TPWS which are provided as discrete deviceselsewhere in the rail vehicle.

Driving position

The normal position from which the driver controls the train, by operating the primary controls, asset out in GMRT2161. The active driving position is the position being used by the driver to drivethe train.

Excessive speed

With reference to provision of TPWS on the approach to speed restrictions, a speed exceeding theoverspeed margin above which derailment risk is considered to require mitigation.

Interleaving

An arrangement where the arming or trigger transmitter of one pair of TPWS track transmitters ispositioned between a different pair of TPWS track transmitters.

Nesting

An arrangement where one pair of TPWS track transmitters is positioned in between a differentpair of TPWS track transmitters.

Overspeed system (OSS)

A TPWS facility whose function is to initiate a brake application on a train that approaches asignal showing a danger aspect, or other location, at excessive speed (also referred to as theoverspeed sensor system).

Primary control

A control essential for the safe driving of a train or rail vehicle, operable by the train driver fromthe normal driving position.

Running line

A line as shown in Table A of the Sectional Appendix as a passenger line or as a non-passengerline.

Set speed

The minimum speed at which a brake application is initiated when a train passes over the trackelements of an active OSS.

Soft key

A type of VDU display using context-dependent physical keys for input adjacent to an associatedlabel within the display area.

Signal passed at danger.

Suppression (AWS and TPWS trainborne sub-systems)

A state of the trainborne sub-system where it is does not provide operational outputs to the driveror initiate brake demands, for example when an alternative train control system is in use and AWSindications and TPWS interventions are not required. The system is still active in monitoring itsstatus and may indicate fault conditions.

Suppression (AWS magnets)

The application of an opposing magnetic field to an AWS permanent magnet to prevent thedetection of the permanent magnet when a train is not required to receive an AWS indication.

Touch screen

A type of VDU display using the display area for inputs by means of programmable sensitiveareas.

Train Protection and Warning System.

TPWS Miniature Loop

A TPWS transmitter loop smaller than the standard loop, which is used at OSS installations on theapproach to buffer stops and certain other locations where speeds are low.

TPWS Standard Loop

A TPWS transmitter loop of standard dimensions, which is used at all TSS installations and atmost OSS installations, except on the approach to buffer stops.

TPWS temporary isolation switch

A switch provided in the cab whereby the TPWS can be temporarily isolated.

Track sub-system

The TPWS track sub-system comprises the components mounted on the track or at the tracksidethat are used to provide the train stop system (TSS) and OSS functionality.

of 133 RSSB

Train Data Recorder (TDR)

A device to record data concerned with the performance of on-board systems. Also known as ‘OnTrain Monitor and Recorder’ (OTMR).

Train stop override

The facility that allows a train to pass a signal at danger without invoking a brake demand causedby the train stop system (TSS).

Train stop system (TSS)

A TPWS facility whose function is to initiate a brake application on a train that passes a signal atdanger without authority.

Train sub-system

The TPWS train sub-system comprises the components mounted on vehicles that are used toprovide TSS and OSS functionality.

Trigger delay

The pre-set period timed by the train sub-system and initiated by detection of an OSS armingfrequency.

Trigger frequency

A frequency generated by the TPWS track sub-system which, when detected by the vehicle,triggers the train sub-system.

Vehicle

For the purposes of this document the term vehicle is used to define that part of a train which isfitted with the AWS and TPWS equipment, where ‘train’ has the same meaning as in section83(1) of the Railways Act 1993.

References

The Standards catalogue gives the current issue number and status of documents published byRSSB: http://www.rssb.co.uk/railway-group-standards.

RGSC 01 Railway Group Standards Code

RGSC 02 Standards Manual

Documents referenced in the text

Railway Group Standards

GERT8000 Rule Book

GERT8075 AWS and TPWS Interface Requirements

GKRT0075 Lineside Signal Spacing and Speed Signage

GMRT2161 Requirements for Driving Cabs of Railway Vehicles

GMRT2185 Train Safety Systems

GMRT2472 Requirements for Data Recorders on Trains

RSSB Documents

RIS-0386-CCS Rail Industry Standard on Signal Overrun Risk Evaluation andAssessment

RIS-0713-CCS Lineside Signalling Layout Driveability Assessment Requirements

RIS-0737-CCS Signal Sighting Assessment Requirements

RIS-0797-CCS ERTMS/ETCS Baseline 3 Onboard Subsystem Requirements:Retrofit

RIS-0798-CCS ERTMS/ETCS Baseline 3 Onboard Subsystem Requirements: NewTrains

RIS-3437-TOM Defective On-Train Equipment

RIS-8270-RST Route Level Assessment of Technical Compatibility betweenVehicles and Infrastructure.(Will replace GERT8270: Assessment of Route Compatibility ofVehicles and Infrastructure)

RS 522 AWS and TPWS Handbook

T902 (RSSB ResearchProject)

TPWS audible warnings

ERTMS/ ETCS driver machine interface options for future train cabdesign

Coexistent operation of ERTMS and Class B (AWS and TPWS)systems: the development and user testing of an integrated DMI

of 133 RSSB

Other References

BS EN 16186-2:2017 Railway applications. Driver's cab. Integration of displays, controlsand indicators

BS EN 50121 Railway applications. Electromagnetic compatibility. General

ERA_ERTMS_015560version 3.6.0

ETCS Driver Machine Interface

LOC&PAS TSI Commission Regulation (EU) No 1302/2014 concerning a technicalspecification for interoperability relating to the ‘rolling stock —locomotives and passenger rolling stock’ subsystem of the railsystem in the European Union

Noise TSI Commission Regulation (EU) No 1304/2014 on the technicalspecification for interoperability relating to the subsystem ‘rollingstock — noise’

The Railway SafetyRegulations 1999

(Statutory Instrument 1999 no. 2244)

AWS and TPWS Application Requirements … · 1.4.1 This document sets out a series of requirements...

Documents

Transcript of AWS and TPWS Application Requirements … · 1.4.1 This document sets out a series of requirements...

Patentability of Computer Implemented Inventions in Europe · The EPC contains two sets of requirements for patentability: • Basic requirements, e.g. novelty etc. • Set out in

Professional Regulation Commission...The TEST BOOKLETS shall conform to the following specifications requirements: NUMBER OF TEST QUESTIONS SETS: Two sets (Test "A" and Test "B"),

T14111-02-12-14-CMS Requirements on Order Sets, · PDF fileCMS Requirements on Order Sets, Protocols, Preprinted and Standing Orders Wednesday, February 12th, ... Give ACLS drugs to

AWS and TPWS Handbook - RSSB Iss 3.pdf · You will need this AWS and TPWS handbook if you carry out the duties of a: • driver • signaller. i This symbol indicates extra information

Utility Services Requirements - Nova Scotia Power · NOVA SCOTIA POWER INC. UTILITY SERVICE REQUIREMENTS Page 3 0 SCOPE This document sets forth the minimum utility requirements for

TPWS - NRemployeesitenremployee.yolasite.com/resources/TPWS Basics_ver1.0 Mar2017.pdf · TPWS Train Protection & Warning System ... AWS’s (including the ramps ... C3 6/160086 Joint

TPWS Deployment – Indian Railways Emerging trends in Train Protection Management and Electric Energy Management System July 2014.

Additional construction requirements BCA Part 3.10 ... · AS 1684.4 Part 4: ... The Australian/New Zealand Standard 1170.2-2011 sets ... Topic 1.11 Additional construction requirements

SPECIFICATION FOR TRAIN PROTECTION & WARNING SYSTEM (TPWS) · Specification for Train Protection & Warning System ... SRS System Requirements Specification ... Specification for Train

Procedures and General Requirements · responses to NVLAP. ... 2.2 Development of technical requirements ... NIST Handbook 150 sets forth the procedures and general requirements under

Requirements Specification - MIT OpenCourseWare · Requirements Specification: A structured document that sets out the services the system is expected to provide. Should be precise

NR/SIG/11231 Signal Maintenance Testing … a TPWS Plug-in Module Part 04/AP01 05 Replace a TPWS Transmitter Loop Part 04/AP02 05 Replace a TPWS Transmitter Loop Following Track Renewals

Developing Feature Sets for Culturally Diverse … and Requirements 2006.pdfDeveloping Feature Sets for Culturally Diverse External End Users: ... Charles E. Gengler ... perceptions

WA Electrical Requirements - Department of Commerce · this updated version of the WA Electrical Requirements (WAER) ... The WAER sets out minimum requirements for all electrical

AWS and TPWS Interface Requirements - RSSB Iss 1.pdf · RSSB Page 3 of 54 Railway Group Standard GE/RT8075 Issue One Date September 2013 AWS and TPWS Interface Requirements Contents

Licensing: Financial requirements - MSMLM · Licensing: Financial requirements . September 2017 . About this guide This guide sets out the financial requirements you must meet as

Diesel Generator Sets C27...NFPA 110 loading requirements • Conforms to ISO 8528-5 G3 load acceptance requirements • Reliability verified through torsional vibration, fuel consumption,

SCHEDULE 1 RISK BASED CAPITAL REQUIREMENTS · SCHEDULE 1 RISK BASED CAPITAL REQUIREMENTS This schedule sets out the Risk Based Capital Requirements for the purposes of Rule 5.1. A

Isolation of TPWS - Indian Railwayrdso.indianrailways.gov.in/works/uploads/File/Reasoned document for... · During the Start of Mission phase the ... that TPWS is bypassed in case

Licensing: Financial requirements - MSMLM€¦ · Licensing: Financial requirements . September 2017 . About this guide This guide sets out the financial requirements you must meet