Highway crossing control system for railroads utilizing a communications

Abstract

Highway crossing protection equipment which operates warning lights or crossing gates is controlled from the train locomotive which enters into an interchange of messages via a radio link with the controller at the crossing. If communication is not established before the train reaches a safe braking distance, the brakes are applied and the train is not permitted to travel into the crossing. Communications between the train and the crossing controller is initiated by the locomotive when it passes a trackside beacon transponder located beyond a safe braking distance from the crossing. The crossing controller transmits a message addressed to the train acknowledging the receipt of the train signal. The message from the crossing controller causes the train to send a subsequent message within a minimum time which is used to update a timer (a minimum time) for the crossing to be actuated to its safe condition. All communications are handles through vital communications logic which activates the protection equipment to its safe condition or sets alarms or brakes in the train in the event of errors or failures in the messages being handled in the crossing controller or in the train equipment, respectively.