Anti-Collision Device (ACD) Network (Raksha Kavach TM ) … A Train Collision Prevention System...

Anti-Collision Device (ACD) Network

(Raksha KavachTM

)

… A Train Collision Prevention System (TCPS)

Ajaykumar A. Bhatt, IRSSE Chief Signal & Telecommunication EngineerKonkan Railway Corporation Limited, India

International Railway Safety Conference Goa 2007

‘Anti-Collision Device (ACD) Network’ – Ajaykumar A. Bhatt, CSTE, Konkan Railway, India 2

Coverage

• Why ACD ?

• Expectations from ACD

• What is ‘ACD Network’ ?

• Installation of ACD Network

• Working of ‘ACD Network’

• ACD Implementation in India

ACD Network … A Train Collision Prevention System (TCPS)


Why Anti-Collision Device (ACD) needed ?

Railway operations today have a ‘limitation’ of ‘single

point’ failure which is built in Driver’s human actions

• At Station – Driver’s failure to either ‘read correct aspect’

or ‘signal itself showing a wrong aspect’ can lead to a

Collision!

• In Mid-section - Driver does not know in ‘advance’ whether –

– A Train is ahead on ‘same’ Track and ‘approaching’ his Train

– A Train is on ‘adjacent’ Track and infringing his Track, may be

after ‘derailing’ and/or ‘parting / jumbling’

– A ‘Non-Interlocked’ Level crossing Gate is in ‘open’ condition

Except what he can see ‘himself’ - to prevent a Collision!


‘Prompted’ Konkan Railway to Develop Anti-Collision Device in Aug 1999


Expectations from ‘ACD Network’

• Elimination of ‘Human Error’ (No User inputs for Operations)

• Design to be ‘Universally Acceptable’ on Railways, namely

– ‘Compatible’ with different types of Signaling systems

– ‘Adaptable’ in both ‘Diesel’ and ‘Electric’ Tractions

– ‘Workable’ in Single, Double & Multiple lines sections

– ‘Suitable’ for existing ‘Train Working Rules’

– No ‘positive’ indication to driver for Train Operations

– ‘Available’ for Train Collision Prevention ‘Globally’

whereas decisions for braking taken ‘Locally’ (continue..)


Expectations from ‘ACD Network’ (contd..)

• Design to be ‘Universally Acceptable’ on Railways, namely

– ‘Maintainable’ (wireless communication, easy to install,

customize, configure, test, commission, repair/replace)

– No ‘track based’ inputs in mid-section

– Limited ‘point detection’ & ‘main line track circuits’

based inputs at stations (for preventing collision with

‘stabled train load’

– ‘Durable’ (Even when failure occurs the impact is local)

– ‘Reliable’ in operation (shall not fail to ‘automatically’

apply brakes when it is supposed to prevent collision and

shall not also ‘unnecessarily’ apply brakes)


ACD Network … A Train Collision Prevention System (TCPS)

What is ‘ACD Network’(Raksha KavachTM) ?


‘ACD Network’ - Definition

•‘ACD Network’ is made of ‘self-acting’, computer based

radio communication devices called ‘Anti-Collision

Devices’ (ACDs)

• When Collision is perceived, it ‘automatically’ applies

brakes to Trains, thereby protecting the ‘Traveling

Public’ from ‘dangerous’ Collision or minimizing the extent

of damages that may be caused due to a Collision

•It also ‘Warns’ Road Users ‘in advance’ of an approaching

Train at a Level Crossing.


Block Schematic of Loco ACD along with ABU in Locomotive

Driver’s Console

•GPS - Global Positioning System

•ABU - Auto Braking Unit, ‘fixed’ adjacent to the Locomotive ACD

COMMAND & CONTROL UNIT (CCU)

(Micro-Processor Based)

Radio Transceiver

Data Entry Key Pad [for

Maintenance]

PowerConverter

LocoBattery

I/O Sub System Fixed Outside Locomotive, Cab

(‘Roof-TOP’)

Braking Signal through ABU*

for Speed Control of Loco

(3 Kms Range)

GPS* Receiver‘POSITION’ TRACKING

through SATELLITE

Visual Audio

Message Display

Antennae

CancelSOS


ABUACD

Installation of Loco ACD - Driver’s Cab – Diesel Loco

Driver’s Console


Loco ACD - Normal Working

Both the Trains travelling on their

respective lines in Block section –

No action by ACD

L 9 9 9 9 9

G 9 9 9 9 9 1 9 : 2 6

Driver’s Console

Self Loco ACD-ID

Self Guard ACD - ID Indian Standard Time (GMT+ 0530 hrs)


‘Portable’ Guard ACD for Passenger Train

Size: 210 x 235 x 130 mm Weight: 6.02 Kg


Guard ACD fitted in Brake Van of Passenger Train


Portable Guard ACD placed on roof-top of Brake Van of a Freight Train

Remote ‘SOS’ of Guard (with Key Chain)


Station ACD[Fitted at a Station & linked to Signalling circuits]

Size: 360 x 350 x 240 mm

Weight: 14 Kg

Size: 165 x 175 x 160 mm

Weight: 2 Kg


Station ACD - Normal Working

When no event is observed by Station ACD –

‘AAAA’ represents the Station Code

A A A A S T N 1 9 : 2 6

Station Master’s Console

Station Code (‘AAAA”)


Gate ACD (Manned Level Crossing )

[with Boom Locking Arrangement]

Size – 250x 270 x 110 mm, Weight - 5 Kg

Lifting Barrier Close/Open Sensing Switch

Boom Locking Sensing Switch


Antenna

Solar Panel

Hooter& Flasher

Anti-theft arrangement

Location Box

Tower – 12 mGate ACD (Un-Manned LC)

Size – 250 x 270 x 110

mm Weight - 5

Kg


ACD on a Train uses GPS for Location Determination

• Constellation of 27 [‘24’ + ‘3’ (spare)] Global Position System (GPS) Satellites formed around the ‘Earth’

• ‘Four’ satellites needed to be in view of GPS Receiver

• Time Stamp (Date & GMT), and other data given by GPS Receiver using ‘Triangulation method’ per second, as under:

– Location (Latitude, Longitude)

– ‘Course Angle’ of Travel (w.r.t. to true ‘North’ of Earth), Basis for identification of change of Track, by a Train

– Speed (in knots)


GPS Satellites

UHF Data Radio Modem

GPS Receiver

Working of “on-board” ACDs

Receive inputs from satellites, communicate with each other using

radio modems & use intelligence to act – To prevent ‘dangerous’

Collisions

ACDs have Knowledge Embedded Intelligence

Inter-ACD Radio Communication

Loco

Loco


ACD Network mainly takes ‘Track-ID’ based

decisions

Station Track-ID (TID) Plan (Stored in a ‘Station ACD’)

P3P2

P17P8

P24

P20

P22

TID=16

P26

P25

P23

P21

P19

P18

P12

P11

P7

P6

P4P1

P5

TID=15

TID=17

TID=14

TID=18

Database of TID Plans of Stations, GPS shadow zones, Level Crossings and Repeaters on ACD Routes are stored in

memory of ‘Loco’ & ‘Guard’ ACDs


Deduction of Change in ‘Track-ID’ by Train bound ACDs - 1 On Points & Crossing – Deviation Count Theory (patented by KRCL)

• ‘Point Zone’ is defined between ‘A’ and ‘B’ on the track.

• Even with a location ‘inaccuracy’ of 25 metres, the Loco/Guard ACD

will not miss the beginning of ‘Point Zone’

• Inside the ‘Point Zone, ‘reversal’ of Angle of travel decides the change

in ‘Track-ID’ of Loco ACD and Guard ACD, as the case may be.

5 m25 m

25 m

‘Point Zone’ connecting ‘Main Line’ to ‘Loop Line’

No change in Angle

3 deg ‘change’ in angle3 deg ‘change’ in angle

3 deg ‘Reversal’ of Angle3 deg ‘Reversal’ of Angle

A A (Lat, Lon)

TID = 15TID = 15

TID = 16

B B (Lat, Lon)


In case of negotiating a points and crossing zone where

DCT is ‘non-workable’, the points position ( i.e. ‘Normal’

or ‘Reverse’ read from signaling circuits), radiated by

Station ACD would enable Loco ACD and Guard ACD to

‘auto-deduce’ the change of their ‘Track-ID’, after

coming out of DPXZ.

Deduction of Change in ‘Track-ID’ by Train bound ACDs - 2 On Dead Points & Crossing Zones (DPXZ) – where ‘DCT’ non workable

Signaling Relay Room

Station ACD

TID = 15TID = 15

TID = 16


Deduction of Change in ‘Track-ID’ by Train bound ACDs - 3 Track-ID (TID) Assignment – While Leaving a Station – SINGLE LINE

SECTION

TID = 15TID = 15

TID = 16

T1

TID = 14TID = 14

In case of Single line section, the ‘UNIQUE’ Track-ID of

the section would be forced on Loco ACD and Guard

ACD of a train, while leaving the Station


In case of Double line section, the ‘valid’ Track-ID of

the section would be communicated by Station ACD to

Loco ACD of train while leaving the Station, based on

occupation of ‘two consecutive’ track circuits at

dispatch end.

Deduction of Change in ‘Track-ID’ by Train bound ACDs - 4 Track-ID (TID) Assignment – While Leaving a Station – DOUBLE LINES

SECTION

TID = 15TID = 15

TID = 16

T1

TID = 14TID = 14

TID = 17Track Ckts.Track

Ckts.


In case of Multiple lines section, two consecutive

track based RF Tags (provided at the dispatch ends of

station) are read by Loco ACD with the help of by ‘RF

Tag Reader’, fitted in the under frame of Locomotive

Deduction of Change in ‘Track-ID’ by Train bound ACDs - 5

Track-ID (TID) Assignment – While Leaving a Station – MULTIPLE

LINES SECTION T1

RF Tags

TID = 15TID = 15

TID = 16

TID = 14TID = 14

TID = 17

RF Tags


Initialization of ACD fitted Train• At Train originating Station, Guard ACD is loaded and switched

‘on’.

• As soon as Train starts, Loco ACD will identify ‘automatically’ its

Guard ACD and radiate its ‘Guard ACD – ID’.

• On receipt of data packet from a Loco ACD containing its ‘ACD-

ID’, the Guard ACD will assume the ‘Loco ACD-ID’ and ‘Track-ID’

of that Loco ACD, thus forming a ‘CYBER’ Train.

• Loco ACD will conduct an ‘Auto Brake Test’ (ABT), moment its

speed becomes 50 Km/hr and reduce it by 20 Km/hr to deduce

the ‘braking characteristics’ of its Train

• ACD fitted train would now apply brakes based on its braking

capacity, whenever a collision-like situation is perceived.


Prevention of Collision in ‘Mid-section’ - 1

Prevention of ‘Head- on’ Collision

TID =11

TID =12

T1T2

Prevention of ‘Rear- end’ Collision

TID =11

TID =12

T1 T2


Prevention of Collision in ‘Mid-section’ - 2

Prevention of ‘Side’ Collision

TID =11

TID =12

Stationary (might have derailed)

T1

T2

Prevention of ‘Side’ Collision

TID =11

TID =12

Train Parted, Derailed & Infringing Adjacent Track

T1

T2


Prevention of Collision at Level Crossing

Manned Level Crossing (Open)

TID =11

TID =12

‘Hooter’ / ‘Flasher’ to give ‘Train Approach’ Warning to Road

Users

T1

Lifting Barrier Gate

TID =11

TID =12

T1

Road

‘Hooter’ / ‘Flasher’ to give ‘Train Approach’ Warning to Road

Users

Un-Manned Level Crossing


Prevention of Collision in Station Area -1

Prevention of ‘Head-on’ or ‘Rear-end’ Collision

TID =11

TID =12

TID =10

T1 T2

‘Station Approach’ Warning to Driver

TID =11

TID =12

T1Station


Prevention of Collision in Station Area - 2

Prevention of High speed Collision with

Train on Loop Line (RNSML)

TID =11

TID =12

TID =10T1

T2

TID =12

Prevention of Collision with ‘Stabled’ Load

on Main LineTID =11

TID =10

T1 SL


Prevention of Collision in Station Area - 3

Prevention of Collision due to ‘Fouling’ (Multiple Lines)

TID =11

TID =12

TID =10

TID =13

T1

T2

Prevention of Collision due to ‘Fouling’

TID =11

TID =12

TID =10T1

T2


‘128’ Train Collisions in FIVE Years on Indian Railways Analyzed by Rly Board (with RDSO & KRCL) –

(April 1997 to January 2002)

23 (18%)1310Total

080701Side Collision3

030102Rear-end Collision2

120507Head-on Collision1

TotalStationMid-Sec.‘Non-Preventable’ by ACD

Sr

105 (82%)6045Total

221606Side Collision3

441133Rear-end Collision2

393306Head-on Collision1

TotalStationMid-Sec.‘Preventable’ by ACDSr


Train Collision Scenarios: ‘Non-Preventable’ by ACD

• ‘Adequate’ braking distance at that speed is not available

when a ‘dangerous’ collision-like situation arises suddenly

• Train derails and its wagons/coaches dash with another

Train, already on ‘adjacent’ track

• Overshooting of ‘Fouling Mark’ by a Train on main line

• ‘Failure’ of brake power of Locomotive due to any reason

• Rolling backward/forward of a ‘Stabled load’

• Other train is a ‘NON’ ACD Train


ACD Project

‘Corporate Safety Plan’ (2003 - 2013), Indian Railways

2013-14Balance ‘ACD Works’

covering 52,600 Route Kms

over

Indian Railways

2

2007-08‘ACD Works’ already

sanctioned on

3,419 Route Kms over

Indian Railways

1

Target for Completion

DescriptionSr


Total Provision of ACDs

Northeast Frontier Rly & Konkan Rly

ACD Project on Req. Spare

Tot

NF Railway 1,382 126 1,508

Konkan Railway 720 98 818

Total 2,132 224 2,326

Loco ACDs - Loco shed wise Req. Spare

Tot

NF Railway ( 13 Loco Sheds ) 589 27 616

Konkan Railway ( 06 Loco Sheds )

111 14 125

Total ( 19 Loco Sheds) 700 41 741


‘ACD Project’ - Works Already Sanctioned over IR

4

Southern Rly (including part of South Western Rly) –

Ernakulam – Shoranur – Palghat – Erode – Chennai

and Bangalore – Jolarpettai – Chennai

3

2

Northeast Frontier Rly –

Pilot Project Commissioned (June 2007)1

Provision of ‘Anti-Collision Devices’ (ACDs) on Broad Gauge (BG) Routes of Indian Railways

Sr

South Central Rly (including part of South Western Rly) –

Vasco – Madgaon – Londa – Hubli – Guntakal – Renigunta

Northern Rly – Jalandhar – Amritsar


7

14

8

12

13

5

5

16

6

9

4

15

3

2

1

10

11


“I need the ACD, ACD does not need me” – Train Driver

‘Anti-Collision Device (ACD) Network’ – © Konkan Railway Corporation Limited, India

Anti-Collision Device (ACD) Network (Raksha Kavach TM ) … A Train Collision Prevention System...

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