Abstract: In the state that a train moves from a track circuit 3T toward a track circuit 5T, and a train detection signal TD1 is supplied from the boundary between the track circuits 3T and 5T to the track circuits 3T and 5T, and the train detection signal TD1 is received by the train, if the signal intensity is suddenly reduced greatly immediately after the axle of the train passes the boundary between the track circuits 3T and 5T, it can be decided that the train passes the boundary between the track circuits 3T and 5T. Therefore, if absolute position information of the track circuit 5T is preserved beforehand in the train, the movement distance calculated from pulse output of a speed generator is corrected (replaced) in the absolute position information of the track circuit 5T, and hereafter is updated by the pulse output, thus the position of the own train can be easily detected as a movement distance.

Abstract: A vehicle signal shunt detection apparatus responds to a first signal to establish the presence of a vehicle including a shunt circuit and then responds to a second signal to establish that the shunt circuit is operating to provide a desired predetermined vehicle signal.