Patent ID: 8752797

Claim:
A sensing device for a rail line comprising: a first sensor detecting a vehicle traveling on the rail line, the first sensor comprising a first coil of wire to inductively couple to a part of the vehicle, the first sensor operable to signal a first detection event; a second sensor detecting the vehicle traveling on the rail line, the second sensor located a fixed distance away from the first sensor, the second sensor comprising a second coil of wire to inductively couple to a part of the vehicle, the second sensor operable to signal a second detection event; electrical circuitry accepting signals from the first and second sensors, the electrical circuitry configured to generate: for the first sensor, a first coupling signal and a first output pulse signal, and for the second sensor, a second coupling signal and a second output pulse signal; and electrical connections electrically connecting the first sensor, the second sensor, and the electrical circuitry; wherein the first coupling signal has a magnitude based on the amount of inductive coupling between the first coil of wire and the vehicle, wherein the first output pulse signal is triggered when the amount of inductive coupling between the first coil of wire and the vehicle is at or exceeds a first predetermined level, wherein the second coupling signal has a magnitude based on the amount of inductive coupling between the second coil of wire and the vehicle, and wherein the second output pulse signal is triggered when the amount of inductive coupling between the second coil of wire and the vehicle is at or exceeds a second predetermined level.