A Rail Network Optimization Model Designed for Freight Traffic
The freight network optimization model presented in this chapter was developed as a support tool for planning and policy decisions involved in the improvement of rail networks on a regional and national level. It is based on a strategic traffic assignment model designed to model macro networks with a high aggregation level, being exclusively designed for freight traffic. The model contemplates road and rail transport modes, and considers two different types of cargo: intermodal cargo, which is generally transported in containers and is easily interchanged between different modes at intermodal terminals; and general cargo, which represents all the remaining cargo. The optimization process is based on a local search heuristic which delivers good solutions in a reasonable computing time, with the quality of each network improvement solution being assessed based on the reduction of the total generalized costs and CO2 emissions. This freight network optimization model is innovative in the fact that it is not limited, allowing for both the improvement of existing links as well as the construction of new ones, and not having a limit on the number or variety of network improvement possibilities. Its adaptability to different conditions is emphasized when the model is applied to a network under two different investment scenarios, by delivering considerably different solutions adapted to the conditions of each scenario.
KeywordsNetwork optimization Freight transportation Traffic assignment
The present study was financed by the Portuguese Science and Technology Foundation.
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