Abstract: A system and method for preventing collisions between vehicles, such as railway vehicles, by exchanging data regarding track position of the vehicles. By use of an on-board track database, the system provides an indication of the distance between vehicles based not on line-of-sight but on track distance. Additionally, a system and method for accurately determining location of railway vehicles without the use of a network of trackside indicators. The disclosed system uses a gyro, position indicator, and a satellite position determination along with a track database to maintain highly accurate estimates of measurement errors and track position.

Abstract: This invention relates to a system and method of detecting a broken rail in a railway system. The track sensing circuitry of the present invention applies a voltage source at each end of a block of rails and senses the current flowing through the circuitry. The present invention will detect broken rails continuously in a block, even with a train present (except for a break directly beneath the train). Since the rail is continuously checked, the only restriction imposed on train spacing by this track circuit configuration is that only one train can be present in a block at a time.