Summary: | This paper presents the formulation of a train formation problem in rail loading stations (TFLS) from the systematic perspective. Several patterns of train formation are analyzed thoroughly before modeling, including direct single-commodity trains, direct multi-commodity trains created in the loading stations, and direct trains originating from reclassification yards. One of the crucial preconditions is that the loading and unloading efficiencies in the loading stations and the relational unloading stations are symmetric. Based on this, a non-linear 0−1 programming model is designed with the aim of minimizing the total car-hour cost incurred by the loading, unloading, and reclassification operations, and the commercial software Lingo is employed as the solving approach. A small-scale example is carried out first to illustrate the validity of the presented model and the effectiveness of the proposed method. Then, a series of numerical cases are devised to test the model and solving approach. The computational results show that our model can be regarded as a theoretical foundation of the TFLS problem.
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