Rail-Truck intermodal transportation for dangerous goods

Rail and truck are primary modes of transportation in North America. However, their use as individual modes has also raised concerns, e.g., congestion due to extensive trucking and accessibility issue of rail due to sparse rail networks. Combining these modes has the ability to overcome challenges and limitations in individual modes. As a result, rail-truck intermodal has emerged as an alternative to individual modes. A key is to efficiently configure associated activities such as inbound drayage, long haul and outbound drayage. To achieve this, there are a few studies that design intermodal networks as a hub and spoke system for regular freight. In this research, we extend the concept of intermodal hub and spoke networks to dangerous goods transportation. Our focus is primarily to address two concerns: i) make use economies of scale during long haul operation, ii) determine routings for inbound and outbound drayage activities from the perspective of risk. To this end, we develop a bi-level model in which the upper-level is a p-hub median single allocation problem to minimize the total transportation cost and the lower level is a routing problem for intermodal shipments to minimize the total transportation risk in the network. We reduce the problem to a single level and illustrate the solution on a prototype intermodal network. We demonstrate its application over an intermodal network between Alberta and Ontario through a case study.