Hybrid applications of constraint satisfaction and meta-heuristics to railway timetabling: A comparative study

This paper provides a discussion on the train scheduling algorithms develop ed to create predictive schedules for a fleet of passenger trains which tra vel along a primarily single-track railway with some double-track stretches , The algorithms are an object-oriented constraint-based heuristic and two hybrid methods, which represent combinations of the heuristic with tabu sea rch and simulated annealing search control strategies, The data of infrastr uctures and working timetables of passenger trains of Iran's railway system are used to evaluate and compare the generated schedules. Three delay-base d performance measures, i.e., sum of weighted waiting times (SWWTs), averag e of unit waiting time (AUWT), and maximum ratio of waiting time to journey time (MRWJ), are used to evaluate the schedules and compare algorithms, wh ere AUWT and MRWJ are introduced by the authors. Simulation experiments sho w the success of the three methods and the relative advantages and disadvan tages of the algorithms are discussed in the paper.