Vulnerability Analysis of Railway Networks in Case of Multi-Link Blockage

:In this paper, we propose a methodology to analyze the most critical links of a railway network based on flow interdiction. Our strategy for network interdiction is to maximize network disruption by removing the links with the greatest impact to the system. For this purpose, we first introduce our primary model to determine vulnerable links based on routing costs, which are based on the minimum cost model. Next, we propose a heuristic approach to solve this model with partial enumeration of network components to assess the most vulnerable parts. Since an important factor in system vulnerability is flow, we introduce the time-space network flow model as the second model to simulate train flow in the network. After interdicting critical links in the railway network, the trains are scheduled in the residual network with considerations of various factors including customer demand, track and station capacities, and time planning horizon. The paper includes a computational instance which has been analyzed by the proposed models under various disruption scenarios, and the results are compared with full enumeration of network components using a network scan method. The accuracy of obtained results indicates the effectiveness of the proposed method in addition to fast computational time compared to the enumeration method.