The precision diagnosis of subway electric multiple units (EMUs) was conducted with various types of engineering analysis techniques for the current performance and wear evaluation. The evaluation was conducted on detailed parts of EMUs, such as car bodies, bogies, braking systems, and electrical systems of EMUs. Several characterization means including nondestructive evaluation techniques, corrosion testing, and three-dimensional measurements, were employed for the evaluation of car bodies and bogies. For braking system, degradation and performance tests were conducted, while the functional and degradation tests were performed on electrical system in order to identify the actual performance of the system. Moreover, stress and structural analyses using commercial finite element method (FEM) software provided important information on stress distribution and load transfer mechanisms. In this investigation, various advanced engineering analysis techniques for the safety analysis of subway EMUs have been introduced and the analysis results have been used to provide the critical information for the criteria of safety assessment.

In order to investigate performance characteristics of deteriorated subway rolling stocks, several engineering assessment methods, such as the acceleration, vibration, and braking performance tests, were carried out on subway electric multiple units (EMUs) with over 20 years operation. According to the testing results, in vibration and braking performance of EMUs, the similar performance results were obtained as compared with newly manufactured EMUs. However, in terms of acceleration performance characteristic, below reference value (3.0 km/h/s) has been obtained. This is mainly due to performance deterioration of EMUs including traction motor. In this investigation, the results on precision diagnosis evaluation of deteriorated EMUs were provided through the overall evaluation of corrosion testing and structural performance of car body in subway EMUs.