VOL. XLIX No.3-4, pp. 407 - 423



Rail track as a lossy transmission line

Part I: Parameters and new measurement methods

Adam Szeląg

Institute of Electrical Machines, Warsaw University of Technology

Manuscript received 2000.04.07, revised version 2000.11.09

The transmission line representation of a two rail track is used in the paper for purposes of prepa­ration the measurements of their parameters. The problem of precise knowledge of rail track impedance and admittance have been usually solved by analytical calculations. The paper presents a new method of simultaneous measurements of parameters of the track, which could be applied for in situ measure­ments.


The problem of proper representations of a railway tracks and the values of their electrical parameters is well known and reported [1, 2, 4, 7, 9, 11, 12, 13]. But mostly only analytical methods of calculations of impedance Z and admittance Y have been used with different stages of simplifications. As the parameters of the track are strictly de­pendent on: local conditions, the soil, weather conditions and may vary in a wide range according to them, the measurements are really the only way to have the idea about their value on the specific area. The knowledge of the track parameters in the presence of ground is a significant factor for analysis of electromagnetic compatibility of traction currents and signalling and control low power equipment. The frequency dependence of these parameters is of a special interest due to propagation of harmonic currents in the contact line and rails caused by power electronic equipment of the high-tech electric traction vehicles.

In many previous works [4+7, 11, 13, 14, 15, 18] the multi-level transmission line theory of track representation has been developed and analytical calculations to find out their parameters have been carried out.


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