Reliability Analysis of the Third Rail System Based on Fault Tree

The third rail system (TRS) plays a significant role in supplying electric current to the metro vehicle in urban rail transit. The failure of its components can influence the operational stability and safety of both the TRS and the vehicle to some extent. In this paper, a fault tree of TRS is established to analyze the failure modes qualitatively and quantitatively. Actual data detected from the TRS in Guangzhou Metro Line 4 are used to carry out fault tree analysis (FTA) and reliability calculation. The result shows the offset and crack of mid-point support and the parameter problem of the third rail are the main modes that cause the failure of TRS in a relative high probability. Conclusions in this research can serve as the reference in the stage of design, maintenance and detection of the TRS.