Patent ID: 7296770

Claim:
A signaling method for a railroad system having a plurality of track sections connected to one another, each of the track sections being bounded by insulated joints, wherein signaling energy is provided to said track sections by a source, said source having line wires connected thereto, the method comprising: measuring a track current on a first one of said track sections at a first location on said first one of said track sections, said signaling energy being provided to said first one of said track sections at a second location on said first one of said track sections; measuring a local voltage on said line wires; determining whether a magnitude of said track current meets or exceeds a threshold value independent of said local voltage; determining whether said track current and said local voltage are nominally in phase with one another in a manner that is independent of said step of determining whether the magnitude of said track current meets or exceeds said threshold value; and providing a first signal only if said magnitude is determined to meet or exceed said threshold value and said track current and said local voltage are determined to be nominally in phase with one another; said first signal being an indication that a train is not present in said first one of said track sections, that said first one of said track sections does not have a broken rail, and that the particular ones of said insulated joints that bound said first one of said track sections do not include a fault condition.