Patent ID: 8505855

Claim:
A train detector for detecting presence of a first train and a second train on a track respectively, by transmitting a train detection signal to a dual gauge track circuit having a first rail, a second rail and a common rail, the first train traveling on the first rail and the common rail, and the second train having a gauge different from the first train and traveling on the second rail and the common rail, wherein the train detector comprises: a first transmitter for transmitting a first train detection signal having a predetermined frequency to the first rail; a first receiver for receiving the first train detection signal from the first rail; a second transmitter for transmitting a second train detection signal having a frequency different from the first train detection signal to the second rail; a second receiver for receiving the second train detection signal from the second rail a first filter connected between the first rail and the first receiver and designed to pass a frequency band of the first train detection signal and to increase an impedance at a frequency band of the second train detection signal so as to suppress a current of the second train detection signal; and a second filter connected between the second rail and the second receiver and designed to pass a frequency band of the second train detection signal and to increase an impedance at a frequency band of the first train detection signal so as to suppress a current of the first train detection signal; so as to prevent deficiency of attenuation of train detection signals when trains are present on the track, the deficiency being caused by mutual induction between the first rail and the second rail, that is specific to the dual gauge track circuit.