A computer algebra approach to the design of routes and the study of their compatibility in a railway interlocking

A railway interlocking is a device that supervises train operation (signaling and position of switches) authorization and prevents conflicting actions from being authorized. An expert system for route selection in a railway interlocking is presented, that is independent of the station topology. It is Maple-based and uses lists (it performs a kind of adapted knowledge extraction and verification). Given the track arrangement, it can determine all routes that begin in a given section and all routes that are an extension of a given route (in both cases it is possible to ask what routes end at a given section). Routes can be classified according to number of sections and, given a time estimate for crossing each section, timing for each route can be calculated. Therefore, the program makes it possible to optimize the route according to different criteria. Moreover, thanks to the chosen data structure, decision making on the compatibility of a proposed route is straightforward.