Signalling | Objectives of Signalling| Types of Signalling

Signalling

Signalling consists of the systems, devices and means by which trains are operated effectively and tracks are used to maximum extend, maintaining the safety of the passengers, the staff and the rolling stock. Railway signalling in its present form was introduced for the first time in England in 1842.

Objective of signalling

1. To regulate the movement of trains so that they run safely at maximum permissible speeds.

2. Ensuring safety between two or more trains crossing each other’s path.

3. To provide facilities for safe and efficient shunting.

4. To regulate the arrival and departure of trains from the station yard.

5. To guide the trains to run at restricted speeds during maintenance and repair of tracks.

6. To ensure the safety of the train when it comes in contact with road traffic at level crossing.

Types of signalling

Signals are classified based on following characteristics

1. Operating characteristics

a. Detonating signal

b. Hand signal

c. Fixed signal

2. Functional characteristics

a. Semaphore signal

b. Warner signal

c. Shunting signal

d. Coloured light signal

3. Location Characteristic

a. Reception signal

i. Outer signal

ii. Home signal

b. Departure signal

i. Starter signal

ii. Advance signal

4. Special characteristics

a. Repeater or co-acting signal

b. Routing signal

c. Calling on signal

d. Point indicator