Scheduling of trains — An optimization approach

Abstract

A model for scheduling freight-trains, considering one section in the railway network, has been developed. The model is a network flow model with ensuring efficient algorithms. The model has been tested on data from the Danish State Railways.

The model may as well be used for longterm planning e.g. finding the optimal capacity of the section considered as for short term control e.g. the bi-annual changes of the schedule.

The model is set up with reference to real life applications and has appeared to be able to include the major part of the technical and operational constraints.

In real life the scheduling of trains is a very complicated and troublesome task to do manually. A mathematical model can not entirely make up for the experience and the ability of an experienced scheduler. What the model can do is to help him get a survey of the problem and to do some of the boring computional work. Therefore, in this paper it has been the general aim to set up rather simple models which partly optimize, partly ensure most constraints from the application in question to be fulfilled. Thus, the model is an addendum to the scheduler who has to verify the solution given by the model, who can preditermine parts of the solution, or in other ways combine his general knowledge of the railway system with the flexibility and the rapidity of the model. This might in general be the road ahead for using optimization models in real life applications.