Single wagonload (SWL) transport is a type of transport in which a train consists of railcars from different senders and receivers. Railcars with the same direction are assembled in nodes to form trains that travel to the next node. At each node, the railcars are reassembled until they reach their destination. Due to its low impact on the climate compared to other modes of transportation, the market share is expected to grow. This leads to an increased utilisation of infrastructure. In particular, the nodes in the SWL network, the so-called marshalling yards, are to be mentioned as bottlenecks, which are thus highly susceptible to congestion. This is aggravated by the fact that it is a system with limited capacity and surrounded by many uncertainties.
The aim of this paper is to identify and analyse the economic costs of rerouting railcars to avoid congestion in marshalling yards on the operational level. This adds a rerouting-specific component to the railcar routing costs found in existing literature. All relevant costs, both monetary and non-monetary, are identified and then mapped in a novel mathematical optimisation model. The objective of the model is to minimize network costs concerning the routing of railcars including costs for detours and delays. Capacity restrictions of the network are taken into account.
An optimisation model-based approach seems to be suitable for identifying the influence of different costs in the short-term routing of railcars in order to enable an ultimate cost optimisation in short-term planning. It allows existing methods of operations research to be applied and examined for their suitability for the novel model.
In order to fulfil the aim of this paper we conduct computational experiments to model and systematically analyse different scenarios. By applying our approach, we identify the most impactful cost factors and thus contribute to a better understanding of rail freight network costs and their dependencies on the operational level. In addition, correlations between the identified costs are expected to be revealed by the analysis and synergy effects can thus be found.
This work contributes to the optimisation of the most cost-efficient short-term rerouting of railcars in single wagonload transport.