Patent ID: 7823842
Filing Date: 2010-11-02
Classification: A63H

Abstract:
1. A model train detection circuit for use with a segment of track in a model railroad layout having two rails of opposite polarity across which a flow of electrical current drives a model train, comprising: a polarity reversing relay circuit; a polarity switch operatively coupled between a source of electrical power and said first and second rails of said track segment, said polarity switch including a double-pole, double throw switch configured to respond to said polarity reversing relay circuit; wherein said polarity reversing relay circuit is further configured to selectively energize said track segment with a polarity matching said adjacent track segment in response to a signal from a train detecting circuit configured to detect the presence of a model train by a directional flow of electrical current from an external power source, through the model train electrically coupling the two rails on the adjacent track segment and which is traveling towards said track segment; and wherein said polarity reversing relay circuit includes a clamping diode configured to prevent transistor leakage current from accidentally energizing said polarity reversing relay circuit.