To address the urgent need for a fault testing and verification platform for traction drive systems in rail transit vehicles, this chapter focuses on the technical challenges of fault injection, fault testing and verification, and platform implementation in the development of semi-physical simulation platforms for traction drive systems. This chapter outlines some new methods and technologies for the developing high-speed train traction drive system fault testing and verification platforms, and then introduces a real-time simulation platform that integrates real-time simulation, realistic fault behavior simulation, random fault testing, and fault diagnosis algorithm assessment for traction drive systems in rail transit vehicles. Finally, a real-time simulation platform for fault testing and verification of high-speed train traction drive system developed in cooperation with a leading unit of traction drive system in China is introduced. The platform can not only realistically simulate the common fault scenarios in high-speed trains, but also objectively and comprehensively evaluate the fault diagnosis algorithm, providing a test and verification environment and basis for further optimization and debugging of the fault diagnosis algorithm and whether it can meet the decision of onboard applications.