Patent ID: 7566032

Claim:
A model train detection circuit for use with a segment of track in a model railroad layout having two electrically isolated rails of opposite polarity across which a flow of electrical current drives a model train, comprising: a diode defining a first electrical pathway coupled between a first rail of the track segment and a source of electrical power; a transistor defining a second electrical pathway coupled between said first rail of the track segment and said source of electrical power, a base of said transistor coupled to said first rail, an emitter of said transistor coupled to said source of electrical power, and a collector of said transistor coupled to an external electrical circuit; wherein an electrical current is selectively routed from said source of electrical power, to a second rail of the track segment, and over said first electrical pathway in response to said first rail having a first polarity together with the presence of the model train on the track segment completing an electrical connection between said first and second rails; and wherein an electrical current is selectively routed from said source of electrical power, to a second rail of the track segment, and over said second electrical pathway in response to said first rail having a second polarity together with the presence of the model train on the track segment completing an electrical connection between said first and second rails.