Microprocessors in a traction environment: the LUL experience

London Underground Limited (LUL) have lived with microprocessors in train-bourne equipment for over ten years. The earliest microprocessor based system gave cause for concern for two reasons: firstly they did not perform as well as originally expected and secondly they did not last as long as they should. The author describes the various advantages and drawbacks of each of the numerous microprocessor-based systems employed in the past. As LUL moves into the 1990s, it will see increasing application of advanced technology on the new Central and Northern Line stocks. These stocks will make more more extensive use of train microprocessors and advances are expected in the size of component used, and the language in which the system will be programmed