Engineering safety diagnosis of crashed subway electric multiple units (EMUs) was
conducted for safety assessment. Several advanced engineering analysis techniques including
nondestructive evaluation (NDE) techniques and stress and structural analyses programs, were
performed for better understandings and exploration of failure analysis and safety concerns. NDE
techniques such as ultrasonic testing and magnetic particle testing, were used to detect
manufacture-induced and/or in-service defects and collision-induced flaws, and measure the
dimensions of deformed and non-deformed parts on damaged EMUs due to a rear-end collision.
Moreover, stress and structural analyses using commercial I-DEAS software provided important
information on stress distribution and load transfer mechanisms as well as the amount of damages
during the crash. A good agreement has been found between structural analysis results and the results
of actual damages in EMUs during crash. 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 safety assessment of crashed EMUs.