MINIMIZING WAITING-TIMES IN INTEGRATED FIXED-INTERVAL TIMETABLES BY UPGRADING RAILWAY TRACKS

The integrated fixed interval timetable of a railway network guarantee s none waiting times for passengers changing trains. For a periodicall y served network such a timetable only exists, if and only if the runn ing times of the trains are feasible with a group equation system. If the running times are infeasible with this equation system, there will remain a certain amount of waiting time. A modification of the runnin g times can be achieved by reforming the actual state of certain track segments. In this paper we discuss the cost-benefit between the inves tigation for reforming track states and the quality of the resulting t imetable measured by the remaining waiting times. This leads to a comp licated bi-criteria optimization problem. We generate sub-optimal solu tions by a hybrid genetic algorithm including fuzzy logic. (C) 1997 El sevier Science B.V.