Formulation and solution of a combined train routing and makeup, and empty car distribution model

This paper presents the formulation and solution of a combined train routing and makeup, and empty car distribution model. This formulation results in a large scale mixed-integer programming problem with nonlinear objective function and linear constraints. A heuristic decomposition technique is developed to solve the model. This solution procedure exploits the special structure of the problem and decomposes it into smaller subproblems based on the type of decision variables. Model testing results are also presented.