Remote control of traction power over two wires

In 1979 British Rail introduced new equipment to the Edinburgh/Glasgow route, using push-pull operation to avoid lengthy turn-round delays at the terminal stations. This paper describes the design and development of the equipment ultimately provided to allow this operation, without expensive modification of the intermediate coaches on the train, by the use of TDM (time-division multiplex) techniques. The initial testing and subsequent service experience are described. A brief review of the future possibilities for this technique, and other similar equipments available, is provided.