200703 – Wardrop & Caldwell – Application of Problem Space Search to Heavy Haul Scheduling and Infrastructure Planning

Developing train plans for heavy-haul railways is a complex task. Australia’s heavy-haul lines are
predominantly single track, presenting the particular problem of how to cross and pass trains to
maximise capacity and minimise delays.

Timetabling by manual techniques is time consuming and is unlikely to provide an optimal train plan.
The Problem Space Search technique allows many thousands of feasible timetables to be rapidly
developed and then ranked according to performance against such measures as throughput, average
delay per train and cost. This produces a timetable that can be regarded as optimal under the
prevailing conditions.