A unit train, also called a block train is a type of train where 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 all of the same type, and sometimes the cars are all identical. Some common unit trains are coal and taconite, although the most famous is the Tropicana Juice Train.