Multi-resource routing with flexible tasks: an application in drayage operations

This paper introduces an application of a Multi-Resource Routing Problem (MRRP) in drayage operations. Drayage involves the movement of loaded and empty equipment between rail yards, shippers, consignees, and equipment yards. The problem of routing and scheduling drayage movements is modeled as an MRRP with flexible tasks, since the origins and destinations of some movements can be chosen from a set of possible nodes. The complexities added by routing choice are studied, along with the impact of these complexities on problem formulation. The solution approach developed to solve this problem includes column generation embedded in a branch-and-bound framework. Using this approach, efficient operating plans are designed to coordinate independent drayage operations in the Chicago region.