Cascading Failure in Multiple Critical Infrastructure Interdependent Networks of Syncretic Railway System

A syncretic railway network (SRN) that comprises the railway, regional railway, and urban rail transit is the cornerstone for the socio-economic development of urban agglomerations. Most existing research studies consider a syncretic network as a single network, and therefore, they cannot capture the interdependent patterns in the network. Thus, the characteristics of interdependent node/edges and robustness of the interdependent critical infrastructure of the SRN remain under-researched. In this study, we investigated the critical infrastructure interdependent networks (CIINs) of the SRN. To this end, we designed a cascading failure model based on the real data of the CIINs of the SRN in the Chengdu-Chongqing urban agglomeration, and we examined the cascading failure in both the syncretic and single networks. Our results indicate that robustness decreased with increasing the number of layers for a targeted attack on the highest connected nodes of the theoretical coupled network. The robustness of the theoretical coupled network was inferior to that of the single-layer network, whereas the robustness of the actual network was contrary to this result. The robustness of the CIINs in the SRN with different coupled modes increased with an increase in the number of nodes/sections of the single-layer network forming the interdependent network. However, it decreased with an increasing number of interdependent nodes/sections. Further, the robustness of a load-based SRN was found to be extremely sensitive to the failure of higher-load stations, therefore, it is important to facilitate decision-making processes in the daily operations and emergency management of the SRN.