Optimising cyclic timetables with a SAT approach: EPIA 2017

Abstract

This paper describes the preliminary results of an ongoing research on cyclic railway timetabling, namely on optimising timetables with respect to travel time using Boolean Satisfiability Problem (SAT) approaches. Some works already done in the field of railway timetables propose solutions to the optimisation problem using Mixed Integer Linear Programming (MILP) and SAT. In this work, we propose a binary search procedure which uses a SAT solver to get global minimum solutions with respect to travel time, and a procedure which is being developed to compute a better upper bound for the solution value and speed up the search process. Finally, we present some promising preliminary results which show that our approach applied to real world data performs better than existing SAT approaches and a state-of-the-art MILP approach.