In Korea, high-speed train(HEMU-400X) system with distributed power is being developed, and the highest test speed of this train is 400km/h. This developed the first high-speed train as a distributed power train in Korea, as well as for the development of train system and evaluation system included evaluation technology is needed. Accordingly, a comprehensive and efficient OMS(Overall Measurement System) was build up for verifying the performance of HEMU-400X. By the case study of the G7 and TTX, OMS of HEMU-400X was improved the test performance and maintainability. In particular, the existing Window-based systems has a limit to the control, due to this reason OMS applying enhanced RT(Real-time) system. In this study, compare the advantages and disadvantages of RT systems with Window-based systems, as well as the configuration of the RT systems.