A quantitative approach for assessing the critical nodal and linear elements of a railway infrastructure

Determining the priority of infrastructure assets is an important problem in critical infrastructure protection. However, relatively few studies have attempted to address the problem. This paper presents a quantitative approach for determining the elements of a railway infrastructure that have the highest protection priority. The train stations in a railway infrastructure (nodal elements) and railway lines (linear elements) are modeled as nodes and ties, respectively, in a social network diagram, which is used in centricity analysis to explore the relative importance of train stations. A modified gravity model is presented to assess the importance of railway lines. The feasibility of the proposed methodology is demonstrated using the railway infrastructure of Mainland China. The methodology can help practitioners and policy makers obtain a better understanding of the importance and protection priority of railway infrastructure assets as well as other critical infrastructures that have network topologies.