Risk analysis on Beijing metro operation initiated by human factors

Human factor- (passengers and operators) related accidents in the complex metro system can affect the metros' operation resulting in catastrophic failures. This research aims to present the causal chains of Beijing Metro operation risks initiated by human factors and discuss the uncertain logic relationship between events in the chain and possibility fluctuation of event's occurrences. The research methodology combines Cause Consequence Analysis (CCA) and Fuzzy Causal Model (FCM). CCA expresses the interactions between multiple failures and protective mechanisms whereas FCM models the uncertain incidence relationship between events and possibility fluctuation of human-factor event occurrence. Nine causal chains of metro operation risks were drawn out based on the historical incident data and procedures for operation and staff communications during an emergency. The calculated possibility for the top event occurrence of several types of incidents shows similar trends with historical operations' incident data. The results show that the time intervals with the highest possibility of a risk event occurrence of type "passenger is clamped by door," influenced by operator fatigue, are 13:00 to 15:00 and 21:00 to 24:00. Also, the results show that the proposed methodology is applicable to the prediction of metro operation risk.