Patent ID: 6527230
Filing Date: 2003-03-04
Classification: B61L

Abstract:
A system for use on a locomotive having a traction motor which generates a first magnetic field during operation, the system comprising:a track receiver having a coil of wire wrapped around a core that has a longitudinal axis that defines an axis of sensitivity where the track receiver is most sensitive to magnetic fields propagating therealong, the track receiver located on-board the locomotive and disposed in a second magnetic field produced around at least one of a pair of rails on which the locomotive is carried in response to a cab signal carrier propagating through the at least one rail, for converting the second magnetic field into a cab signal, the track receiver also disposed in the first magnetic field generated during operation of the traction motor of the locomotive for converting the first magnetic field into a noise signal; and a cab signal system located on-board the locomotive and connected to receive the cab signal and the noise signal from the track receiver, the cab signal system configured to extract data from the cab signal which has a frequency range at least partially in common with a frequency range of the noise signal, wherein: the first magnetic field propagates in a three dimensional space around the traction motor and the first magnetic field has at each point in the three dimensional space a magnetic vector which, with reference to a Cartesian coordinate system, is comprised of a horizontal component which extends parallel to the longitudinal axes of the rails adjacent the locomotive, a lateral component which extends laterally to the longitudinal axes of the rails adjacent the locomotive and a vertical component which extends perpendicular to the horizontal and lateral vectors; the track receiver is oriented in the first magnetic field so that at the points in the three dimensional space where the track receiver is positioned a vector sum of at least two of the horizontal, lateral and vertical components of the first magnetic field has a direction vector that propagates through the track receiver substantially perpendicular to the axis of sensitivity of the track receiver; and the track receiver is oriented in the second magnetic field so that a direction vector of the second magnetic field produced around the at least one rail propagates through the track receiver substantially parallel to the axis of sensitivity thereof.