Radio communication applications in people mover systems

While existing automatic train control functions exchange occupancy and speed command information via track circuit systems, a second communication path for non-control functions is performed by the people mover's radio communication system. This subsystem, originally started as a simple emergency voice and alarm system, has evolved into a sophisticated wireless data transmission system. Once used only for rudimentary alarms and the occasional emergency voice call, today's systems are used for remotely initiating on-board non-vital functions from the wayside. Such functions include triggering on-board graphics and recorded announcements, initiating diagnostics, and live public address announcements. The next generation of people movers will depend on radio communications for train control functions, replacing the functions that are now performed through track circuits.