Knowledge-based Locomotive Planning for the Swedish Railway

Abstract

This report describes a study done as a masters thesis during 1998 within the Complex Operations Laboratory (COL) at SICS. The report describes a vehicle routing and scheduling problem occurring in the planning of rail traffic at the Swedish State Railways (SJ). The report contains a comprehensive description of the problem and describes several techniques that can be used to address the problem: Constraint Programming with a particular model (due to Helmut Simonis) of the routing problem. This model requires an efficient implementation of a particular called global constraint: the geometric diffn constraint. A propagation algorithm for a 2-dimensional version of this constraint is outlined in the report. The use of insertion heuristics to solve this class of problems have been in general use for some time. And adaption and evaluation of some of these heuristics are also analyzed in the report