Vulnerability Assessment and Reduction for Intermodal Freight Transportation Networks

Intermodal freight transportation networks (IFTNs) are critical for global logistics, facilitating the efficient transportation of cargo within containers by integrating diverse transportation modes. However, such integration exposes IFTNs to a variety of disruptions, may leading to degradation in transportation capabilities. Thus, vulnerability assessment and reduction (VA&R) for IFTNs are of practical significance. Despite its importance, this research problem has received little attention in the literature. To fill the research gap, we propose the VA&R problem for IFTNs, considering uncertain disruptions that impact IFTN nodes and links, along with cascading failures and influence spreading. We further build models incorporating two-stage robust optimization to assess and reduce the impact of uncertain disruptions, and build exact solution methods for VA&R utilizing column-and-constraint generation and speedup strategies to identify non-conservative solutions. The effectiveness and efficiency of our modeling and solution methods are demonstrated by comparing them to benchmark modeling and solution methods, through numerical experiments for a real-world international IFTN. Furthermore, managerial insights and recommendations for IFTN operations are achieved based on comprehensive sensitivity analyses to address uncertain disruptions in IFTNs.