A diesel multiple unit or DMU is a multiple-unit train powered by on-board diesel engines. A DMU requires no separate locomotive, as the engines are incorporated into one or more of the carriages. Diesel-powered single-unit railcars are also generally classed as DMUs. Diesel-powered units may be further classified by their transmission type: diesel–mechanical DMMU, diesel–hydraulic DHMU, or diesel–electric DEMU.
A JNR Class KiHa40 in use for Erimo Express service, Hokkaido, Japan
An IE 29000 Class diesel multiple unit on a western commuter service at Dublin Connolly Rail station, Ireland
A British Rail Class 185 diesel hydraulic multiple unit operated by TransPennine Express at Manchester Piccadilly station, United Kingdom
One of the underfloor diesel engines with hydraulic transmission under a car of JR Shikoku 2700 series DMU
An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number of the carriages. An EMU is usually formed of two or more semi-permanently coupled carriages, but electrically powered single-unit railcars are also generally classed as EMUs. The great majority of EMUs are passenger trains, but versions also exist for carrying mail.
A DART 8500 class commuter EMU at Howth Junction railway station, Ireland.
A 6-car Siemens Nexas EMU arrives at Flinders Street station on the Upfield service in Melbourne, Australia.
A Liverpool Overhead Railway carriage in the Museum of Liverpool. The first EMUs in 1893.
The prototype unit of JNR 201 series on public display at Harajuku Station in Tokyo, 13 May 1979. Next to it, a Yamanote Line's 103 series train can be seen passing through