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6. Gate barriers
  
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Railway
Sri Lanka
Gate barrier protects the level crossing. In the color light area gate barriers are automatically operated when a train approaches it from either direction. The gate machine has 110V d.c. motor to operate the gate. It also consists of contacts to get indication of the status of the gate. The figure below illustrates a gate barrier system.

The gate barrier has two signals on the track on either side of the road.  The signal at the distance is called an early warning. It has two aspects of amber and green. The five lamps are arranged in a manner to represent letter "W" for Warning. The amber aspect means the gate is not protected. This signal is located at a distance to allow the driver of the train to apply brakes and stop the train if necessary. The green aspect means the gate is protected and the train can pass the gate at its normal speed. The signal near the gate has a similar arrangement; red on top unit and green on lower unit. If the gate is protected the green aspect will be lit and if not the red.

The gate barrier system also has flashing two unit warning signals on either side of the track for the road traffic. A warning bell is also fixed on the mast. It rings before and while the gate is closing. The circuits are wired in such a manner a failure on the gate motor circuit will result in the continuous ringing of the bell. In such an occasion the gate-man will inform this to the nearest station master using the gate telephone and he in turn will inform the STI.

 

 
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1. Introduction ] 2. Track Circuit ] 3. Relays ] 4. Signals ] 5. Moter Points ] [ 6. Gate barriers ] 7. Automatic Blocking System ]

R. Jayanthan
Last updated on 01 January, 2002