Communicating vital control signals

摘要: A railway vehicle control system comprises a track (1) and plurality of transponders (N, N+1, N+2) at predetermined positions along the track. (2) moves track, having means (20, 21) for detecting each transponders. location has (4, 5, 6, 7, 7a) periodically transmitting vital safety signalling information to via radio link. In response detection one transponders, sends first message link in reception by location, is sent time from link, then second