ABSTRACT
Although much effort is currently devoted to develop models and methods capable of analyzing interdependent infrastructure systems, for an overview of methods and models see Pedersen et al. (2006), the developments are still in a quite rudimentary stage (Little 2002; Rinaldi, 2004). Furthermore, the methods and models address the same issue, the impact of interdependencies, but from different viewpoints. We argue that different models and methods are necessary in order to illuminate the issue of interdependencies, i.e. there is no universal model. Since the challenges to understand, characterize, and model these systems are immense, there is a continuing need for research on this topic. The aim of the present paper is to introduce a model that can be used when analyzing the vulnerability of interdependent technical infrastructure systems. The modeling approach is based on earlier work of the authors (Johansson et al., 2007; Jönsson et al., in press) and on ideas from network analysis (e.g. Newman, 2003). In order to demonstrate the applicability of the model it is used to study the vulnerability of a fictional electrified railway system, which consists of the physical railway track, two internal electrical power systems, a telecommunication system and in-feed points from external electrical distribution systems.
