Freight Car Utilization and Railroad Reliability:An Assigned Fleet Model. Studies in Railroad Operations and Economics. Volume 24.

摘要

This report presents a simulation model that can be used to evaluate the relative impacts of various shipper and railroad actions to improve the performance of assigned fleets. Shipper behavior is modelled as his ability to load goods,relative to his production rate and empty car availability. If empty cars are not available,the goods are stored in a warehouse. Railroad origin-to-destination performance is described by a trip time distribution,reflecting mean transit time and unreliability. At the receiver,cars are detained until demand for them arises,or they are unloaded into a warehouse. Service is measured in terms of the backlog of goods warehoused at the shipper,the number of stockouts at the receiver,and the characteristics of the queue at either end. Results of the model show that railroad operating improvements can effectively increase the capacity of the fleet. By improving mean times or reliability,railroads can improve the level of service to shippers without adding cars to the fleet. Shipper actions,such as increasing warehouse capacity,may also improve service and utilization of the fleet. The model was tested in a case study involving the Milwaukee Road and the Miller Brewing Company.