Travel Updates


Signal failure

What is a signal failure?

The signalling system is used to control the running of trains throughout their journey and ensure that trains are on the correct route at the right time to complete their journey safely.

The signalling system includes: 

  • The signal centre - where staff use the signalling system to regulate train running, including changing the colour of the signals and operating points to set the correct route for trains 
  • The signals – the red, yellow and green lights, similar to traffic lights, seen at stations, on overhead gantries and at the track side 
  • Track points – the moveable sections of track, and the method of moving the points, that allow trains to move from one track to another 
  • Signal cabling - the cables used to connect the signals and points to the signal box to allow staff to use the signalling system 
  • Track circuit – a simple electrical system used to detect the precise location of trains on the rail network

A signal failure may occur because:

  • Signal cabling is damaged or stolen
  • Track points fail to operate correctly
  • Track circuits become faulty so that the precise location of trains cannot be correctly identified
  • The electrical supply to the signalling system fails

The smooth operation of the signalling system is essential to ensure that trains run safely and on time.

A signal failure means that trains cannot run correctly and delays to trains will occur whilst the problem is identified, corrected and/or an alternative method of moving trains through the affected area is put in place.

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Last updated:   12 March 2013