Railway signalling

• Railway Signal- apparatus used to provide nonverbal, safe and precise information to driver

• Aspect- How signal appears ( Red, Yellow& Green )

• Indication- Information provided by aspect

• ON aspect- Most restrictive aspect ( RED for Stop Sig)

• OFF aspect- Other than ON aspect ( Yellow / Double Yellow/ Green )

Two Aspect Lower Quadrant Signalling

I. Stop Signal

Upper Quadrant Semaphore Signalling

I. Stop Signal

Multiple Aspect Colour Light Signals

I. Stop Signal (Three aspect)

Need for Signaling in Railways:

• Signalling in railways has evolved for the following:

• Running trains safely by securing it`s intended path.

• Handle more trains effectively.

• Unambiguous & Timely Communication to Loco Pilot for regulating speed of train

• The Train Loco Pilot is very much dependent on the aspect of the signal for controlling the speed of train

Railway Signalling conveys the following

• Timely information to Loco Pilot for regulating speed of his train.

• Information is conveyed by a signal showing various aspects.

. Many signals are interlinked for giving advance information.

 signal ensures;

• Physical clearance of intended path.

• Securing various points in the path.

• Closure of Level crossing gates.

• No other train is moving in this path.