Railway freight wagon fleet size optimization: A real-world application

Railway freight wagons have a significant share in the total capital assets of a railway freight company. Due to this fact, the main objective of every company is to maximize the utilization of these resources and on that way minimize its size. In this paper we consider a real-world freight wagon fleet management problem and propose a decomposition approach for optimization of the heterogeneous fleet of flat wagons. The approach has four steps: random container weight generation, optimal container to wagon assignment, empty wagon repositioning and optimal wagon fleet sizing. For the purpose of validation, real-life experiments were conducted based on a rail network composed of 911 origin-destination links and the yearly demand of more than 3 × 10⁶ empty and loaded 20-foot and 40-foot containers. Experimental results show that proposed approach has a practical applicability and that in comparison with existing experience-based practice it represents a significant improvement for the flat wagon fleet management.