An automatic speed enforcement system for heavy freight trains

An automatic speed enforcement (ASES) system is described that was developed specifically for use on heavy general merchandise, unit, and intermodal trains. With this automatic system, a microprocessor generates a speed profile corresponding to a specific change of cab signal. The system monitors train speed and, following a downward change of cab signal, requires that train speed be gradually reduced as the train moves farther into the block. The engineer can use a minimal air brake application, throttle reduction, dynamic braking, or a combination of the three to comply with the speed limit safely. A penalty brake application is imposed when the speed profile is violated. The automatic train control system was overlaid onto an existing continuous cab signal system