We discuss the network representation method for calculating railway fares. The railway system has a typical network structure consisting of stations as nodes and railbeds as arcs. When we, however, try to represent junctions on the network, we encounter some problems. For example, there are several complex junctions that cannot be represented by integrating nodes associated with the junction or introducing dummy arcs with a distance of zero for a connection node on foot. We show an idea for network representation in order to apply algorithms to the shortest path problem, which is the basis for calculating railway fares. Our surrogate network finds the shortest path between two specified stations exactly.