Scheduling transshipment operations in a multiple inbound and outbound door crossdock

Cross-docking is a logistic technique which seeks to reduce costs related to inventory holding, order picking, transportation as well as the delivery time. Little attention has been given to the transshipment operations inside a cross-docking platform. Most of the existing work in this domain is limited to scheduling of operations for a restricted class of cross-docks, such as the mono input and output platforms. In this article, we study the transshipment scheduling problem in a multiple inbound and outbound dock configuration. In the cross-docking facility under study, transshipment operations are performed based on the decisions taken at the supervisory level. Incoming products are either directly loaded to an outbound truck, if the truck is already available at an outbound dock, or they are temporarily stored incurring a unit holding cost. The supervisor can also decide to replace an outbound truck to facilitate direct loading but this decision costs a unit replacement cost. The objective is to find the best schedule of transshipment operations to minimize the sum of inventory holding and truck replacement costs. In this article, we present 2 heuristics to attain this objective. Several numerical experiments are presented. The results are compared with the optimal solution to evaluate the performance of the method.