Identifying location of vehicles

Abstract From the Canadian patent

ABRIDGMENT, An automatic system of locating and controlling vehicles travelling along a trackway wherein, transponders are located at intervals along the track in irregular sequence and/or at irregular spacings, the code numbers of these transponders not being all unique (but not necessarily all equal). Information concerning passage past each responder distance run is transmitted from each vehicle to a remote control station where there is a central controller that responds to the information received and sends out commmand signals to the vehicles.