High Quality Content by WIKIPEDIA articles! Advanced Civil Speed Enforcement System (ACSES) is a positive train control cab signaling system developed by PHW and Alstom. The system is designed to prevent train-to-train collisions, protect against overspeed and protect work crews with temporary speed restrictions. The information about permanent and temporary speed restrictions is transmitted to the train by transponders lying in the track, coded track circuits and digital radio. It is installed on Amtrak`s Northeast Corridor between Washington and Boston.