Unit train

A unit train, also called a block train or a trainload service, is a train in which all cars (wagons) carry the same commodity and are shipped from the same origin to the same destination, without being split up or stored en route.^[1] They are distinct from wagonload trains, composed of differing numbers of cars for various customers.^[2]

Unit trains enable railways to compete more effectively with road and internal waterway transport systems. Time and money are saved by avoiding the complexities and delays that would otherwise involve assembling and disassembling trains at rail yards near the origin and destination.

Unit trains are particularly efficient and economical for high-volume commodities. Since they often carry only one commodity, cars are of all the same type; often identical. Some commodities (e.g., coal) can be loaded at the origin while the train moves slowly on a loop track. The procedure is reversed at the receiving end, and because there generally is not any commodity to be hauled in the opposite direction, the train returns empty. In the United States the Santa Fe is credited with operating the first true unit train, hauling coal from a mine near Raton, New Mexico to a steel mill at Fontana, California.^[3]