Improved Empty Freight Car Distribution

Abstract

In this paper we consider the problem of distributing empty freight cars in a railway company. We describe and analyze the current planning process, identify the shortcomings of the process, and stress the importance of a reliable distribution process for satisfying customer demand and reducing capital costs. We show how the process can be improved using an optimization model which includes capacity constraints on the trains and adheres explicitly to the arrival and departure times of the trains. The optimization model can be characterized as a multicommodity network flow model with integer requirements. Computational tests show that the model can be solved in acceptable time for real size problems, and indicate that the model generates distribution plans that can improve the quality of the planning process.

Optimization of empty container movements in intermodal transport

“…The planning horizon should be at least as long as this transportation time. (Holmberg et al, 1998;Choong et al, 2002;Nilsson, 2002) Finally, Choong et al (2002 empirically show that the length of the planning horizon may affect mode choice and repositioning costs in a multimodal network, as will be discussed in Section 2.7.…”

Empty container management for intermodal transportation networks

“…In the general transportation area, Holmberg et al (1998) evaluate the impacts of planning horizon length on a model for empty freight car distribution at Swedish State Railways. They propose a multicommodity network flow model with integer requirements.…”

Planning Empty Container Relocations Under Uncertainty

“…A multi-commodity network flow optimisation model was formulated by Holmberg et al [12]. The optimisation model addresses capacity constraints and strictly adheres to arrival and departure times.…”