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(last edited July 19, 2005) Front Page | Recent Changes | Title Index | User Preferences | Random Page | HelpA development of electro-pneumatic (e-p) brake control is the digital control system. It is normally only used on multiple unit trains. It incorporates the fail-safe features of the air brake but eliminated the need for a brake pipe. The brake pipe is replaced by a "round the train wire" which is permanently energised. As long as it remains energised, the brake remains released. If it loses current for any reason, an emergency application follows.
Each car is equipped with a relay valve with can operate the brake in up to seven steps. Three control wires are used in different combinations to actuate the seven steps of braking. They are de-energised to apply the brake and energised to release. Control is from the driver's brake handle in the cab or it can be by an automatic system such as ATO.
A well-known version of digital brake control is the Westcode system by Westinghouse.
