A remote control locomotive is a railway vehicle that provides the motive power for a train that differs from a conventional locomotive in that a remote control system has been installed to one or more locomotives within the train, using either mechanical or currently radio transmitter and receiver system is used to operate it, by a person not physically located at the controls within the confines of the locomotive cab. They have been in use for many years in the railroad industry, including industrial applications such as bulk material load-out, manufacturing, process and industrial switching. The systems are designed to be fail-safe so that if communication is lost the locomotive is brought to a stop automatically.
One of the earliest remote control locomotives was the , which replaced the GWR steam rail motors on both operational cost and maintenance grounds. When running 'autocoach first', the regulator is operated by a linkage to a rotating shaft running the length of the locomotive, passing below the cab floor. This engages (via a telescopic coupling) with another shaft running the full length below the floor of the autocoach. This shaft is turned by a second regulator lever in the cab of the autocoach. (See photograph sequence below.) The driver can operate the regulator, brakes and whistle from the far (cab) end of the autocoach; the fireman remains on the locomotive and (in addition to firing) also controls the valve gear settings. The driver can also warn of the train's approach using a large mechanical gong, prominently mounted high on the cab end of the autocoach, which is operated by stamping on a pedal on the floor of the cab. The driver, guard and fireman communicate with each other by an electric bell system.
In the United States remote controlled locomotives have been in use since the 1980s. In 1988, the Occupational Safety and Health Administration issued a Hazard Information Bulletin regarding their use. By 1999 Canadian National Railway had 115 locomotives equipped with remote control equipment, covering 70% of flat-yard switching and all of its hump yard operations. Canadian National estimated a savings of CDN$20 million per year vs. traditional switching operations.