Railway Signalling.pptx

Describes about Railway Signaling system

1. Railway Signalling

2. Railway Signalling It is a mechanism by which information is conveyed to the T rain Operator/ Train whether to Stop, Proceed or go with caution. Why Signalling???

3. Evolution Police men were posted in regular intervals like stations, level crossing, Point area etc. They indicates to train driver using Hand signals Hand signals are replaced by Multi colour Flags.

4. Evolution Flags to Semaphore signals.

5. Semaphore signals Are rectangular arm fixed to a vertical post Operated by metallic wires manually. The arms are rotated in different angles which conveys different meaning to the train driver. Semaphore signals has later evolved to accommodate the “ fail-safe principle” Signals

6. Signals Semaphore signals to Light signals Uniform in day and night No mechanical moving parts. Hence less failure, maintenance Signals are in the eye level of driver, enhancing visibility.

7. Point operation

8. Point operation Concept Throw Lock Detect Step by step process Initially will be in locked condition Point unlocked Operated to the different direction Locked in the new position Electrically the new locked position is detected and proved.

9. Point operation Manual operation

10. Point operation Electrical operation

11. Concept of “Fail safety” Definition: Incorporation of some feature for automatically counteracting the effect of an anticipated possible source of failure The system/equipment needs to be designed in a manner that any anticipated failure will not infringe the safety of the train. This will be achieved wither mechanically or electrically.

12. Concept of “Fail safety” What If the wire of a semaphore signal breaks??? Proceed Stop

13. Concept of “Fail safety” What If the wire of a semaphore signal breaks???

14. Time interval based Signalling: No information about the actual position of the trains available for the signal man In this type signalling the Signal men will allow the next train to proceed after some fixed time from the departure of the previous train, assuming the previous train would have crossed adequate distance Distance interval based signalling:

15. Distance interval based signalling Signalling system is operated based on the actual location of the trains. In this type signalling the detection of train needs to be done.