Research on the urban rail transit disaster chain: Critical nodes, edge vulnerability and breaking strategy

The rising number of disasters poses significant challenges that are influencing the operation safety of urban rail transit systems. However, most studies to date have focused on individual disasters or types of disasters of urban rail transit, while few have focused on urban rail transit disaster chains. This paper collects 562 urban rail transit disaster cases and builds a disaster chain network model of urban rail transit systems based on complex network theory. The vulnerability of the disaster chain network is analyzed in terms of nodes and edges, and targeted chain -breaking disaster mitigation strategies are proposed, based on the nodes and edges found to have more substantial intermediary roles. The main results of this study show that: (1) disaster nodes have larger clustering coefficients and smaller average path lengths. The disasters "power failure", "fire", "thick smoke and poisonous gas", and "signal and communications system problem" are of high importance and cause a greater loss of network efficiency when removed. (2) The edges "power failure - terrorist attack", "thick smoke and poisonous gas - passenger uncivilized behavior", and "signal and communications system problems - operation error" have higher vulnerability and cause a greater loss of network efficiency when removed. (3) Developing breaking strategies for these disaster nodes and edges in advance can achieve faster chain disconnection and disaster reduction.