POINTS & CROSSINGS, and

SIGNALLING & INTERLOCKING

Points and Crossings• These are the arrangements provided in a

railway track to divert a train from main line to branch line

• TurnOuts: pair of points and a crossing, to divert a train• Left hand turnout: if train is diverted to left of main track in facing direction• Right hand turnout: if train is diverted to right of main track in facing direction

Right hand turnout

Tongue rail

Left hand turnout

Both left and right hand turnouts

Technical terms• Main track or main line• Branch track• Flange way clearance• Stock rails• Tongue rails• Stretcher bar• Switch• Toe of switch• Heel of switch• Throw of switch – 9.5cms for B.G• Facing points and facing direction• Trailing points and trailing direction• Check rails• Wing rails• ANC• TNC

Through sleepers• Sleepers provided under both railway tracks i.e

main line and branch line • Purpose is to maintain both tracks at same level

Interlaced sleepers• Sleepers laid when long sleepers are not available

Types of crossings• to transformed from one track to another

parallel track • Various tracks available are• Diamond crossing• Cross over• Scissors cross over• Ladder track or gathering lines• Gauntlet track

Diamond crossing• It consists of 2 acute angles and 2 obtuse angles

Cross over• Provided when one track is to be diverted to

another parallel track• It consists of 2 set of points and 2 acute crossings

Scissor cross over• Combination of one cross over with the another

one in opposite direction

Ladder track or gathering lines• Number of parallel lanes are connected

Gauntlet track• When two tracks of same or different gauges

running parallel to each other, they are converted into single track at bridges for economizing

SIGNALLING• It consists of systems, devices and means by which

trains are operated efficiently and tracks are used to max. extent

Objectives of Signalling• Facilities for efficient movement of trains• Safety between trains• Max use of track• To guide trains movement during maintenance and

repairs of track

Classification of Signals1) Operation Characteristics

1) Detonating (Fog or Audible) signals2) Hand (Visual Indication) signals3) Fixed (Visual Indication) signals

2) Functional Characteristics1) Stop or Semaphore type signals2) Warner signals3) Shunting signals4) Coloured light signals

3) Locational Characteristics1) Reception Signals: Outer & Home signal2) Departure Signals: Starter & Advance starter

Operation Characteristics1) Detonating (Fog or Audible) signals: during the foggy &

cloudy weather when hand or fixed signals are not visible, detonators are placed on rails which explode with a loud when train passes over them. Generally placed before 400-500m ahead of the signal to enable the driver to stop the train or to obey it.

2) Hand (Visual Indication) signals: hand signals are given by flags fixed to wooden handle or by bare arms during day times and lamps with glass sides or green, red and amber during night times. Generally used by guards, station masters, cabin man, gang man, key man or any authorised man.

3) Fixed (Visual Indication) signals: theses signals are usually fixed at a place.

Functional Characteristics1) Stop or Semaphore type signals: ordinary position is Horizontal but it can be lowered to any angle by pullingthe wire from cabin. ON indicates stop or danger, OFF Indicates proceed.2) Warner signals: similar to semaphore signal at the entrance to station except a V-notch at free end

3) Shunting (Disc or ground) signals: used for shunting operation at station yards.

Shape of circular disc with red band on a white background. The disc can revolve in a vertical plane by pulling the lever arm.

• Horizontal positions indicate STOP• Inclined position (450) indicates PROCEED4) Coloured light signals: with the introduction of electric traction, semaphore signals are replaced by colour light signals both during day and night.

05/01/2023

Locational Characteristics1) Reception Signals: Signals which control the reception of

trains into a station. They are two types i.e Outer & Home signal

Outer signal – it is fist stop signal at a station and it must be placed at adequate distance(0.54km for B.G and 0.4km for M.G) before railway station.Generally a warner signal is provided. In stop position, driver must stop train at a distance of about 90m before outer signal and then proceed to home signal with cautionHome signal – this signal indicates which line is to be usedSo main function is to protect the sidings already occupiednot more than 180m away from the start of switches2) Departure Signals: Signals which control the despatch of trains from the station. They are two types i.e Starter & Advance starter

• Starter signals – it is last stop signal at the station. It is the limit upto which trains at a station come to stand or halt.

• Advance starter – it is last stop signal at station. It indicates that train has left the station and station master is no more responsible of station master. 180m beyond the switches