In rail transport, a train consists of a single or several connected rail vehicles that are capable of being moved together along a guideway to transport freight or passengers from one place to another along a planned route. The guideway (permanent way) usually consists of conventional rail tracks, but might also be monorail or maglev. Propulsion for the train is typically provided by a separate locomotive, or from individual motors in self-propelled multiple units. Most currently operating trains are powered by diesel engines or by electricity supplied by trackside systems. Historically the steam engine was the dominant form of locomotive power through the mid-20th century, and other sources of power (such as horses, rope, gravity, pneumatics, or gas turbines) are possible as well. |