Automatic Train Protection

From Free net encyclopedia

Automatic Train Protection (ATP) is a system installed in some British trains in order to protect the train and avoid a possible catastrophe. This system uses light and sound to warn the train driver of passing a red signal, and applies brakes if the driver fails to respond to these warnings. The system takes into account the speed and position of the train in issuing the warnings and applying the brakes.

In the early 1990s, following the Clapham Junction crash in December 1988, and two other fatal accidents in early 1989 caused by SPADs (Signal Passed At Danger), British Rail was keen to implement the ATP system right across the entire British railway system. However, the cost of this (estimated at over £1bn) was baulked at by the sitting Conservative government, who were preparing the company for privatisation. In the end, the system was only installed on two lines - the Great Western Main Line and the Chiltern Main Line.

All of First Great Western's HST trains are fitted with ATP, and are not allowed in passenger carrying service unless the system is functioning. This requirement is in response to the Ladbroke Grove rail crash.

ATP can refer to protection systems in general, as well as particular implementations.

ATP is given permitted speed and location information from the track via encoded balise(s), encoded track circuit or more recently via radio.

See also

• Automatic train protection system
• Automatic Warning System
• Train Protection Warning System
• Automatische treinbeïnvloeding (ATB) – a Dutch system which would have prevented the Harmelen train disaster.