Portable measurement equipment for site determination of rail track parameters

This paper describes a computer-based automated test procedure for measuring the loop and rail-rail transmission line parameters of rail track. Measurement data from short-circuit and open-circuit tests are subjected to signal averaging to extract noise, followed by Fourier decomposition to extract the amplitude and phase of the fundamental. Sample results are presented for track impedance and admittance in the frequency range 1 Hz to 25 kHz. The methodology is generic in that it can be applied to any track length and any two-rail system including catenary-rail circuits for traction power networks and rail-rail circuits for track signalling systems.