An optimization model for renewal scheduling and traffic flow routing

TL;DR

This paper presents a bi-level optimization model combining scheduling of railway renewal projects with traffic flow adjustments, aiming to improve planning efficiency before timetable creation.

Contribution

It introduces a novel mixed integer and network flow bi-level approach for railway renewal scheduling and traffic flow management.

Findings

Model tested with computational experiments

Effective scheduling and traffic adjustment strategies identified

Supports economical planning before timetable development

Abstract

This document is the third sub-report from the research project SATT (Samplanering av trafikp{\aa}verkande {\aa}tg\"arder och trafikfl\"oden, modellstudie / Coordinated planning of temporary capacity restrictions and traffic flows, model study). The report summarizes the modelling alternatives that have been considered. The main result of the model study is that we propose a bi-level approach for handling the two parts of the problem, i.e. the scheduling of renewal projects and the subsequent adjustments of railway traffic flow. The contributions are: (1) a mixed integer formulation for scheduling project tasks, and (2) a network flow formulation for establishing the possible volumes of railway traffic during the imposed capacity restrictions of these project tasks. The intended usage of the model is for economical planning of a specific production year, which takes place before the timetabling process starts. This document introduces the problem and gives a full description of (1) along with results from computational experiments that have been conducted with this model. An accompanying report gives the details of the final formulation of (2).