POTENTIAL FOR NATIONWIDE POOLING OF VARIOUS TYPES OF RAILROAD CARS.

All opportunities for triangularizing loaded-car movements in order to minimize empty-car miles are investigated. The minimum empty-car-mile repositioning requirements of various railroad car types are presented from the perspective of the entire United States, regardless of car ownership. The optimization algorithm (a car-mile minimization transshipment over the U. S. railway system) ensured that supply and demand for specific types of cars were satisfied. This analysis simulates an efficient utilization of a nationwide pool of each type of car. Supply-and-demand data were obtained from the 1980 1 percent waybill sample. Data on loaded-car miles (L), minimum empty-car miles (E), and E/L ratios are given. Also presented are computer-graphic renderings of the nationwide distribution of the supply and demand for each type of car and directionally specific actual loaded and simulated optimal empty-car flows. Cars analyzed were trilevel automobile carriers, 50-ft gondolas, refrigerated boxcars, open-top hoppers, open-top hoppers carrying coal, covered hoppers, and tanks carrying corn sweetener.