A model for the blocking of trains

We have developed a nonlinear, mixed-integer programming model for the railroad blocking problem. The objective of this model is to determine a classification strategy for all the classification yards in a railroad system at one time. The model can be viewed as a multicommodity flow problem with many additional side conditions. In this paper, we develop the model by discussing variables, constraints, and the objective function in great detail. We are currently attempting to solve this model using MPSX/370.