Risk study of subway passenger compartment door switching system combining STPA and DEMATEL-ISM

Accurate risk identification and analysis are the foundation for ensuring subway operation safety and an effective way to improve it. The passenger compartment door opening and closing system was taken as the research object, a risk analysis model combining system theoretic process analysis (STPA) and decision-making trial and evaluation laboratory and interpretive structural modeling (DEMATEL-ISM) was constructed to complete the systematic identification and importance analysis of risk factors, and to identify the risk transmission paths that may cause system-level hazards. Based on this analysis, risk prevention suggestions were proposed. The results indicate that electronic door control unit (EDCU) core processor failure and EDCU internal power module damage are key causal factors, while abnormal operation of the screw, motor, and nut components and improper operation by the driver are key result factors. These factors all involve multiple risk transmission paths that may lead to system-level hazards and should be given close attention.