Assessment of the changes in the input resistance of the rail circuit during the movement of railway rolling stock

This paper examines the feasibility of locating rolling stock on a track section based on the track line's input impedance, taking into account the influence of its hardware parameters and external factors. The aim of the paper is to evaluate the feasibility of using the track section's complex input impedance to pinpoint rolling stock locations in conventional track circuits. The article presents the results of modeling changes in the track section's input impedance using a 25 Hz code track circuit, traditionally used on railways in the Russian Federation and the CIS. Three basic track circuit calculation modes were used as input data: normal, shunt, and control. Using the analytical expressions of classical track circuit theory for these modes and the Smath Studio software package, graphs were obtained of the active and reactive components of the complex input impedance versus insulation resistance, the ordinate of the rolling stock's location, and the location of the rail break. The simulation results demonstrated that it is possible to use the complex input impedance of a track section to determine the location of rolling stock with an accuracy of 50 meters and pinpoint the location of a rail break with an accuracy of 100 meters. These results can be used in the development of rolling stock tracking systems, including high-speed vehicles, as well as in diagnostic systems for rail network components, which will ultimately enable the transition to predictive failure detection systems.