High-speed train with its reliable, fast and high loading capacities, has attracted more and more attention in the recent years. With the increasing requirements of the speed and safety of the train operation, a lot of efforts has been devoted to the control design for high-speed trains. Similar to the other complex systems, high-speed train formed by the sensors, motors, electrical components, mechanical drives and so on, will have failures with the long time (distance) operation, which could lead to the delay and even stop of the train. Regarded as the heart of the high-speed train, the traction system provides traction power for the entire system. The faults in the traction system may appear in different locations, such as motor, converters, control units, sensors, and so on. These faults can affect the effectiveness of traction force, and result in reduction of speed or may even stop the train. Thus, it is critical to study fault diagnosis and fault-tolerant control problem for high-speed train traction systems.This monograph presents a systematic and comprehensive description of the problems of fault diagnosis and fault-tolerant control of high-speed train traction systems in the presence of faults, external disturbances, and unknown uncertainties. It offers readers with a deep understanding and insight into the safety of high-speed train traction systems, suspension systems and the corresponding design methods. The fault diagnosis and fault-tolerant control methods presented in this book can provide guidance to engineers to improve safety in rail transportation and other related fields. This book is suitable for scientists and researchers in the field of systems and controls, railway transportation engineers, control engineers, lecturers and teachers, graduate students, undergraduate students, and especially those working in the field of high-speed train system control.