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Vehicle presence detection system

  • US 6,292,112 B1
  • Filed: 12/14/1999
  • Issued: 09/18/2001
  • Est. Priority Date: 06/25/1992
  • Status: Expired due to Fees
First Claim
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1. A train presence detection apparatus for use with a level crossing warning system, the apparatus comprising:

  • at least one passive magnetic detector provided at ground level or buried below ground level near rails of a railroad track at a distance from said level crossing for detecting a plurality of magnetic field disturbances caused by ferromagnetic objects passing overhead on said track;

    magnetic field reversal detector connected to said passive detector for detecting reversals in a magnetic field detected by said passive detector and outputting a reversal signal; and

    train presence analyzer analyzing said reversal signal and outputting a train presence output signal.

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