Electric Multiple Unit

An electric multiple unit, commonly abbreviated EMU, is a self-propelled passenger train made up of two or more carriages joined together, in which the traction motors are built into several of the carriages themselves rather than concentrated in a single separate locomotive, drawing power from overhead wires or a third rail. This distributed arrangement differs from a conventional locomotive-hauled train, where every carriage except the locomotive is unpowered, and it lets one driver control the whole train through multiple-unit train control while giving the train stronger acceleration and better performance for frequent stops. Electric multiple units are the dominant vehicle type on commuter and regional rail lines and on rapid-transit and subway systems, especially in areas of high population density, and the format also underlies many high-speed train fleets, including Japan's Shinkansen and Germany's ICE 3.