A Structured Model for Rail Line Simulation and Optimization

A general purpose model of a railway line is presented. This model is based on an algebraic structure which describes the movement of trains over the line. This structure permits an arbitrary number of different trains with differing speeds and priorities to be dispatched over any line configuration including single or multiple tracks and sidings with restricted switching or cross-overs. Both optimization procedures and simulation models of the line can be implemented using this framework. The problem of line blockage at high traffic intensities is discussed, and conditions are given to ensure this does not occur. Computationally simple feasibility tests are presented together with a behaviorally based dispatching model. The model is implemented as a general purpose discrete event simulation model in which different dispatch goals or criteria can easily be included. Details of a validation example involving very high traffic intensity over a typical Canadian rail line are presented.