Patent ID: 7292144

Claim:
An apparatus for use with a railroad dragging equipment detecting (DED) system that detects objects hanging from and dragged beneath a train as the train travels along rails of a railroad track, said DED system having an impact element fixedly mounted to a shaft extending generally between the rails, wherein the impact element includes at least one surface that is impacted by an object hanging down from said train to the impact surface when the train and object pass the impact element, and wherein the impact element rotates from a first position to a second position, and wherein a cam/follower system translates the rotational motion of the impacted element to a linear movement, said apparatus comprising: a signal generator for supplying an input signal; a magnetic amplifier coil coupled to the signal generator to form a circuit which is responsive to the supplied input signal to affect an impedance of the circuit, said magnetic amplifier coil comprising a coil being wound on a magnetic amplifier core; a magnet generating a magnetic field positioned near the magnetic amplifier core for varying the impedance in the circuit, said magnet fixedly mounted to the cam/follower system, wherein said cam/follower system moves the magnet relative to the magnetic amplifier coil when the impact element rotates from the first position to the second position, and wherein moving the magnet varies the circuit impedance; a detection circuit for generating an output signal as a function of variations in circuit impedance; and a controller responsive to the output signal for activating an alarm when the magnet moves relative to the magnetic amplifier coil.