Patent ID: 6158696
Filing Date: 2000-12-12
Classification: B61L

Abstract:
A railroad accident prevention system in combination with a railroad crossing having railroad tracks passing through said railroad crossing and with at least one gate arm which is lowered from an upright gate open position to a horizontal gate closed position under control of a remote controller activated when a train approaches along said railroad tracks to said railroad crossing, comprising:at least one ground-retractable vehicle barrier means for preventing penetration of a vehicle to said railroad tracks when said gate arm is in a closed position; anddrive means for switching said gate arm between said upright gate open position and said horizontal gate closed position, said drive means being activated by a signal from said remote controller;a first sensor means capable of sensing the presence of an obstacle on the path of said train through said railroad crossing when said at least one gate arm is turned into said closed position;an alarm means capable of generating a signal selected from an audible signal and a visible signal;first interlock means connected to said drive means and interlocking said at least one sensor means with said alarm means for activating said alarm means when said sensor senses said obstacle with said at least one gate arm in said closed position; anda second sensor means located at a point ahead of said railroad crossing on the way of said train, said second sensor means being responsive to the presence of said train; and second interlock means between said second sensor means and said alarm means for deactivation of said alarm means in response to the train when no obstacle is sensed by said first sensor means on the railroad crossing;wherein said first interlock means and said second interlock means are switching means selected from electromechanical relays and a solid state relays, said first interlock means and said second interlock means being connected to said alarm means through a respective controller and said relays, said first and second sensor means comprising a resonance-type oscillating circuit consisting of an oscillating voltage generator, a capacitance, and a sensitive element capable of violating resonance conditions of said oscillating circuit in response to a mass of an object stuck on said railroad crossing.