A study on the compensation capacitor in ballast track circuit

A part of the signaling systems related to a rapid transit railway is using the track circuit to detect trains and to deliver train operation services on carriage. Because the interval of one block for a rapid transit railway is as long as 1500 [m], transmission of signal information throughout a track circuit has some troubles. So a compensation capacitor should be installed every 20 [m]. Moreover, if three or more of compensation capacitors are broken down, transmission of signal information throughout a track circuit is not possible. It may cause accidents such as a train collision. In the paper, it was suggested installing a compensation capacitor by using a resonance phenomenon on a track circuit, and the position and size of the compensation capacitor were computed. We demonstrated it with PSpice program.