Solving Combined Blocking and Train Makeup Problem with Ant Colony Optimization

The railroad blocking problem and train makeup planning are the two important decisions in the rail freight transportation planning. The combined railroad blocking and train makeup model that is a network design model combines these two problems in a single model. There are theoretical and empirical evidences that network design models are NP-hard. In this article a metaheuristic solution method based on elitist ant system is proposed to solve this model, and with an example we show how this approach can be implemented