In recent years, the Western Line of Taiwan Railway Administration (TRA) in the metropolitanareas have been rapid transit systematized. At the same time, the line capacity is near saturation.Therefore, the impact from electromechanical equipment failures on the operation is becoming moresignificant. The reliability of the overhead catenary system affects the operational safety and servicequality directly, so the improvement of the overhead catenary system reliability is definitely animportant and urgent issue.

In accordance with the principles of the European Standard EN50126, both the qualitative andquantitative analyses of reliability on the overhead catenary system of the TRA Western Line (both theMountain Line and the Coast Line are included) were conducted with the fault tree analysis method.The results show that the messenger wires are the weakest link in the overhead catenary system, andtherefore the improvement work is needed. The mean time between failures (MTBF) of the overheadcatenary system per hundred kilometers is about 198 days, which provides an important reference forsetting up the system maintenance cycle. In the study, it also explored the overhead catenary systemmaintainability and availability, and explained the inherent correlation of the RAMS. Meanwhile, italso proposed solutions to improve the reliability of the operational phase as the follows: adopting highreliability components, adopting easier-to-replace and modularized components, and fostering trainedand experienced maintenance personnel.