A consist of freight cars, usually dedicated to a single commodity and/or origin and destination, which customarily is not broken-up except for special maintenance work on a component. (For passenger trains, see "Train Set.")
a freight train that moves carloads of a single product between two points. By unloading on arrival and returning promptly for another load, such trains cut costs because they eliminate intermediate stops in yards and reduce cycle times.
A combination of coal cars, typically open top hopper cars, of 100 or more, which are kept together as a unit, moving coal from one mine to one customer, often being dedicated to the movement of coal from one mine to one power plant.
A unit train, also called a block train is train in which all the cars making it up are shipped from the same origin to the same destination. This saves the hassle of assembling and disassembling trains at rail yards near the origin and destination, however, unit trains are only economical for high-volume customers. Since unit trains carry only one commodity, cars are of all the same type, and sometimes the cars are all identical.