Railway Engineeringy g g

Fall Semester

20 Sept 10 to 12 Jan 11

The positive thinker sees the invisible, feelsthe intangible and Lecture – 14

CE – 408

the intangible, and achieves the impossible.(Anonymous)

Sequence :Sequence :

Railway Stations & YardsRailway Stations & Yards

Signaling & InterlockingSignaling & Interlocking

Railway StationRailway Station

• Classification based on Operational requirement: TheClassification based on Operational requirement: The track is divided in number of segments called blocks for operational requirements. No train can enter or leave block ith t i i St ti l t d t th d f thwithout permission. Stations are located at the ends of the 

blocks. 

STATION SECTIONBLOCK SECTION

1/4 MILES

WARNER HOMEOUTER STARTER

Figure 4- 2 CLASSIFICATION OF RAILWAY STATIONS

Class A. Permission to approaching train is given after the linei l d f di t f t l t ¼ il b d h i lis cleared for a distance of at least ¼ miles beyond home signalor up to starting signal. Or Such a station is one where the LineClear indication for the block may not be given unless the linewhere the train is to be received is clear at least for up to thestarter signalClass B. Permission to approaching train is given before lineClass B. Permission to approaching train is given before linehas been cleared for the reception with in station section orlimits. Or Such a station is one where the Line Clear indication

b i b f th ti f th li ithi th t timay be given before the section of the line within the stationhas been cleared for reception of a train. Branch lines androutes with lower running speeds fall into this category.

Class C. Simple block huts where trains do not stop . Or withlight traffic or where no trains are booked to stop, such as an

d bl kintermediate block post.

No Block Station. (Class D). These are stopping placessituated between two consecutive block stations but do notsituated between two consecutive block stations but do notform boundary of any block stations.

Key siding station. Where siding is provided.

Flag Station. Where no siding is provided.

Special Station. Those not working in Class A, B, C or D.

Railway Stationl f b d l• Classification based on Functional requirement:

Halt Station. Server underdeveloped traffic areall b h li d l t igenerally on branch lines and slow trains may

stop here.Wayside Station. On this arrangement is made to

cross over a slower train by express train or upd d iand down trains.

Junction Station. Here branch line meets the mainline so arrangement should be made tointerchange traffic between main and branchlines and clean/ repair of vehicles whichterminate at junction stations.

Terminal Station. The station at which a railwayline or one of its branches terminates or ends iscalled terminal station or terminal junction.Additional arrangements include reversing ofengine (Turntable or Triangle) siding for variouspurposes are needed.

YardsYards

• Yard is system of tracks laid within definite limits for various purposes such as storing of vehicles making of train etc Inpurposes such as storing of vehicles, making of train etc. In yards movements do not follow any time table but certain prescribe rules regulations and signals are followed.Passenger Yards Its function is to provide facilities for safePassenger Yards. Its function is to provide facilities for safe movements of passenger. Passenger platforms are also passenger yards

d d h d d f l d d l d fGoods Yards. These are provided for loading and unloading of goods.Marshalling Yards. The main purpose is to isolate, hold and g p pdispatch wagons to various destinations.Locomotive Yards. Provided for cleaning repairing, servicing, watering and oiling etc of locomotiveswatering and oiling etc of locomotives.

SIGNALING & INTERLOCKING

To prevent running train from cominginto contact with obstruction or othertrain thus providing safety totrain thus providing safety topassenger, staff and rolling stock.To maintain safe distance between

trains running on the same line in thegsame direction facilitating flow thusincreasing capacity.To provide protection at converging

junctions and directional indication atdiverging junction.To provide facilities for carrying outh ti ti f l dshunting operations safely andefficiently.

Signals are used to indicate one or more of the following:

h h li h d i l (f f b i ) bl k dthat the line ahead is clear (free of any obstruction) or blocked.that the driver has permission to proceed.that  points (also called switch or turnout) are set correctly.which way points are setwhich way points are set.the speed the train may travel.the state of the next signal.that the train orders are to be picked up by the crewthat the train orders are to be picked up by the crew.

Signals can be placed:

at the start of a section of trackat the start of a section of track.on the approach to a movable item of infrastructure, such as points/switchesin advance of other signals.on the approach to a level crossingon the approach to a level crossingat a switch or turnout.ahead of platforms or other places that trains are likely to be stopped.

CLASSIFICATION ACCORDING TO FUNCTION

• Semaphore SignalsSemaphore Signals

• Warner Signals.

Stop SignalsStop Signals

• Semaphore: The psemaphore arm of a stop signal is red in front with ain front with a white stripe near the end, and white i th b k ithin the back with a black stripe near the end. The arm is square‐ended. Signal aspects are as shown belowas shown below.

Stop Signals

• Colour‐light The stop signal may have two

Stop Signals

Colour light The stop signal may have two (green above red), three (green‐yellow‐red), or four lamps (yellow‐green‐yellow‐red) asor four lamps (yellow green yellow red) as described above. Aspects are as shown below.

Warner & Stop SignalsWarner & Stop Signals

o Coloured Light Signals.o Improved visibilityp y

o Improved safety

o Higher speed

o Boosts drivers confidence

– Three electric lights are placed on vertical posts which operate

Figurer 5‐3

on vertical posts which operate automatically like disc signal.

• Hand Banners and Flag Signals

• Fog Signals or Detonators

CLASSIFICATION ACCORDING TO LOCATION

STATION SECTION ½ MILES

SIDING

PLATFORMDN WARNER

UP HOMEUP OUTER UP STARTER UP ADVANCE STARTER

PLATFORM

DN ADVANCE STARTER

DN WARNERDN  OUTERDN HOMEDN STARTER

Figure 5-5 TYPICAL SIGNALS LAYOUT

Track Circuit• Eliminates use of human agency to

physically ensure occupation orphysically ensure occupation or otherwise of the track.

• Detects presence or otherwise of a train through an electrical circuit, in which rails form a part of the circuit.

• Prevents reception of a train on anPrevents reception of a train on an occupied line.

InterlockingInterlocking

• In railway signalling, an interlocking is anIn railway signalling, an interlocking is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings. 

• A minimal interlocking consists of signals, but usually includes additional appliances like 

i h d il i d dswitches, derails, crossings at grade and movable bridges. 

InterlockingSome of the fundamental principles of interlocking include:

Interlocking

• Signals may not be operated to permit conflicting train movements to take place at the same time.

• Switches and other appliances in the route must beSwitches and other appliances in the route must be properly 'set' (in position) before a signal may allow train movements to enter that route.

• Once a route is set and a train is given a signal to proceedOnce a route is set and a train is given a signal to proceed over that route, all switches and other movable appliances in the route are locked in position until either – the train passes out of the portion of the route affected, orp p ,– the signal to proceed is withdrawn and sufficient time has 

passed to ensure that a train approaching that signal has had opportunity to come to a stop before passing the signal

Interlocking Principle

• Complete route for reception of train is unoccupied

CHECK

• All points are correctly set & locked

• All Conflicting signals are at Danger

Position(RED)

• Level Crossing gates (if any) are closed

Till Then

All above are True

INTERLOCKING

Tappets and Lock SystemTappets and Lock System

Single Key System

Double Key System 38

Tappets and Lock System

Fi 5 9Figure 5‐9

39

MAIN LINE

BMAIN LINE

ASIDING

Single Key SystemSingle Key System40

MAIN LINEDouble Key System

BMAIN LINE

B

SIDINGCA

K1

K2K1

K2K1K2

DOUBLE LOCK AT A

ONE OF THE KEYS HAVE TO BE IN DOUBLE LOCK TO REMOVE THE OTHER

POINTS CAN NOT BE SET FOR SIDING

KEY IS STRUCK ONCE LOCK OPENS41