Patent ID: 8483893

Claim:
A system for determining number of cars within a train consist, comprising: one or more cars, each car comprising: a frequency generator; and a frequency modifier; at least one ATC (Automatic Train Controller) for the one or more cars; a train line spanning the one or more cars; and a communication network comprising a unique node network address in each of the one or more cars, wherein: each frequency modifier in each of the one or more cars is adapted to receive an input signal at an input frequency and generate an output signal at an output frequency different from the input frequency; the frequency generator in one car provides a predetermined input signal at a predetermined input frequency to the frequency modifier in said one car when said one car is designated as a lead car and the frequency generator of each other car is inactive or is unable to provide an output to the frequency modifier of said car; at least one frequency modifier in at least one of the one or more cars provides its output signal to the train line; and in response to a match or mismatch between the number of cars in the train consist determined by the ATC from (1) the unique node network addresses and (2) a ratio of the output signal to the train line and the predetermined input signal from the frequency generator, the ATC respectively enables or disables movement of the train consist along a path.