Resource considerations for integrated planning of railway traffic and maintenance windows

Abstract

This paper addresses the coordination of railway network maintenance and train traffic. The work extends a previously developed optimization model by considering maintenance resource constraints for crew availability and work time regulations. The aim is to find a long term tactical plan that minimizes the total cost of maintenance and train operations, where train services and train free windows are scheduled such that maintenance can be carried out by a pool of crew resources, which are divided into bases and have limitations on maximum working hours per day and minimum rest time between these working days. A mixed integer linear programming model along with computational experiments are presented which show that these resource considerations can be correctly handled with a moderate increase in model size and solution time.

Coordinating maintenance windows and train traffic: a case study

“…4. Finally, from previous computational results (Lidén et al 2018), we got an indication of the solution times that can be expected in our case study.…”

“…tactical coordination of train traffic and infrastructure maintenance, while handling resource limitations and cyclic (periodic) scheduling. We focus on how cyclic aspects have been treated, and refer to Lidén et al (2018) regarding handling of resource considerations. The publications are divided into three groups: those that schedule infrastructure maintenance (in Sect.…”

“…An exact model is used but the network capacity is controlled with an aggregated approach that does not guarantee a conflict-free timetable. A mathematically stronger model is presented in Lidén et al (2018), which is extended with a maintenance crew resource assignment model such that resource-efficient planning is achieved, while respecting work and rest time regulations. Both these papers use synthetic test instances to show that multi-day problems can be solved optimally with reasonable solution times in a commercial mixed integer solver.…”

“…In this section we describe the optimization model that has been used. It is essentially the same model as presented in Lidén et al (2018), but with minor adjustments in the objective function and some crucial changes in the constraints, which enable a cyclic schedule and varying maintenance window size. We label the model CISMR as an abbreviation for the Cyclic Integrated train Service and railway Maintenance planning problem with Resource considerations.…”

“…Although the monetary volumes cited above indicate a large potential for a more efficient use of maintenance spendings if the coordination with train traffic can be improved, there are few research publications that treat such joint scheduling problems. Lidén and Joborn (2017) presented a macroscopic optimization model for the integrated scheduling of maintenance windows and train services, which was improved and extended with maintenance crew resource considerations in Lidén et al (2018). The methods developed in these previous publications were tested on various theoretical test instances, but were not applied on any practical case, which is the aim of the current work.…”