TRACK TRANSDUCER Russian patent published in 1996 - IPC

FIELD: railway transport; systems to provide safety of traffic; device to record passing of track point by vehicle wheelset and counting of vehicle axles. SUBSTANCE: track transducer 1 has supply voltage source 1 connected to transmitting coil 2 and through phase shifter 7, to one input phase detector 9, receiving coils 4 and connected in opposition and installed along rail. Coils are connected to other input of phase detector 9 through amplitude-phase regulator 8. Transducer has also inductor 6 connected to rail and encased by magnetic circuit of transmitting coil 2. Phase detector 9 checks change of voltage phase at output of amplitude-phase regulator 8 relative to reference voltage. Flip-flop 20 periodically changes its state, and power is supplied to first winding of checking relay 17 through corresponding amplifier 21 or 22 and storage 14 or 15 and OR gate 16. With no train on track generator 12 puts out sequence of pulses and, through analog switches 10 and 11, shunts in turn receiving coils 4 and 5; as a result, pulse trains appear on outputs of phase detector 9 and checking relay 17 gets energized. Failure of any element of circuit or disconnection of transducer from rail courses switching out of relay 17. EFFECT: enhanced reliability of operation. 2 dwg