Planning intermodal drayage network operations

This dissertation presents a model of trucking (drayage) operations that are encountered in rail-truck intermodal service. In these operations loaded trailers arriving at a terminal by rail are delivered to their destinations (consignees) by truck tractors. Also, empty trailers are delivered to shippers, loaded, and delivered to the terminal by truck for the outbound movement by rail. Thus, the problem studied can be described as a multi-unit vehicle operations planning problem, in which loaded and empty trailers must be assigned tractors and then moved between the terminal, consignees, and shippers, while meeting service constraints in form of time windows for delivery or pick up. An optimization model of this process has been developed, but this model is not solvable by standard methods. Two solution methods, termed the Two-Stage and the Multi-Stage procedures, have been developed and are used to solve the model. Both procedures exploit the hidden near-network structure of the model in order to obtain desired integer solutions. The bridge between theory and practice is made by applying the model to a real-world drayage operation case study. The model is used to answer questions regarding reorganization of the drayage operation in order to simultaneously increase efficiency and service quality. The cost of various centralized drayage operations planning alternatives were compared to the total price paid for drayage in the current operation. The results showed that substantial cost savings were attainable from the introduction of the centralized operations planning of drayage over that of current operation. In addition to its usefulness for exploring strategic alternatives, variants or extensions of the model should be useful for tractor-trailer dispatching and day-to-day management. Thus the model points to new areas for research as well