Road switcher locomotive

An ALCO RS-1, generally regarded as the first successful road switcher model
A JNR Class DE10, Japan's most popular road switcher model

A road switcher locomotive is a type of railroad locomotive designed to both haul railcars in mainline service and shunt them in railroad yards. Both type and term are North American in origin, although similar types have been used elsewhere.

A road switcher must be able to operate and have good visibility in both directions. As a road engine, a road switcher must be able to operate at road speeds, with suitable power and cooling capacity. It has high-speed road trucks rather than low-speed switcher only trucks.

Modern road trucks are always equipped with "frictionless" roller bearings, whereas switcher trucks were almost always equipped with "friction" plain bearings, until plain bearings were outlawed in interchange service on both railcars and locomotives.