Freight Car Utilization and Railroad Reliability:The Application of an Inventory Model to the Railroad Empty Car Distribution Process. Studies in Railroad Operations and Economics. Volume 25.

摘要

This report applies inventory control concepts to the problem of sizing empty car inventories at points on railroad networks. Existing car distribution techniques typically flow empty cars from surplus to deficit areas,without considering the inherent variability in both the supply and the demand for empty cars. This report presents a discrete event simulation model of a single terminal area that can estimate optimal inventory levels as a function of supply and demand variability and the cost of holding empty cars for distribution relative to the cost of falling to provide empty cars when required by shippers. The model shows how inventory requirements drop with improvements in trip time reliability,with reductions in variability of supply or demand,and with reductions in the cost of unfilled orders relative to the holding cost. In a preliminary analysis,the model indicated that an excessive inventory was maintained in one surplus area. The report concludes with recommendations for using the model to size empty car inventories on a railroad.