Optimal prepositioning of empty freight cars

Abstract

The optimal utilization and distribution of empty freight cars has plagued the railroad industry in the past and will undoubt edly continue to do so in the future. In this paper we present the methodology for a simulation-optimization model, for the movement of empty freight cars in a hypothetical railroad transportation network. The freight car network is modelled in SLAM and integrated with XMP, a sophisticated and compact linear programming software package, to determine optimal movement and prepositioning of empty cars to the various nodes (terminals) in the network. The simulation model provides the required data structure for the XMP package to execute the transportation linear program and the stochastic linear program. The model is versatile and with the aid of reliable data, could prove to be a valuable tool for railroad managers and engineers.