The Underground Railway is a term used to refer to a network of transportation systems that are located beneath the surface of the ground. The most common forms of these systems are metros, subways, and tubes. Metros are rapid transit systems that are usually found in large cities and are typically operated by a government agency. Subways are similar to metros but are usually privately owned and operated. Tubes are underground railways that are usually found in smaller cities and towns. All three of these systems provide efficient and cost-effective transportation for commuters.