A classic Belgian multiple unit of type 74

A multiple unit is a passenger train whose carriages have their own motors, either diesel ("DMUs") or electric ("EMUs"), and do not need to be hauled by a locomotive. Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... 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. ... Tourists in a vis-a-vis, Prague The classic definition of a carriage is a four-wheeled horse-drawn private passenger vehicle with leaf springs or leather strapping for suspension, whether light, smart and fast or large and comfortable. ... A motor is a device that converts energy into mechanical power, and is often synonymous with engine. ... The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas containing oxygen (usually atmospheric air), rather than a separate source of ignition... A diesel multiple unit can be: a multiple unit powered by a diesel engine; one or more of these form a passenger train; a combination of diesel powered locomotives operating under the control of one engine-driver, coupled together consecutively, usually at the head end of the train, which further... Electric motors of various sizes. ... Great Western Railway No. ...

History and description

Multiple units (MUs) were made possible by the development of multiple-unit train control by the American inventor (Franklin J. Sprague), originally to allow newly electrically-powered rapid transit trains to be operated from a single position without the need for a separate locomotive, as was required when such trains were hauled by steam engines. Multiple-unit train control sometimes referred to simply as multiple-unit or MU, is a method of simultaneously controlling all the motors in a train including a number of self-powered cars from a single operating location. ... An inventor is a person who creates new inventions, typically technical devices such as mechanical, electrical or software devices or methods. ... Frank Julian Sprague (1857-1934) American inventor, Father of Electric Traction Frank Julian Sprague (1857–1934) was an American naval officer and inventor who contributed to the development of the electric motor, electric railways, and electric elevators. ... Electricity is a property of certain subatomic particles (e. ... Rapid transit - Wikipedia /**/ @import /skins/monobook/IE50Fixes. ... A steam engine is a heat engine that makes use of the potential energy that exists as pressure in steam, converting it to mechanical work. ...

Sprague solved the problem of operating all of the train's motors simultaneously from a single position. Before his successful invention, differences in the speed and response of motors on different cars of the train caused binding on the couplings between the train cars, wheel slippage and excess wear on motors and operating gear running at speeds faster or slower than the overall speed of the train, or even derailment, as well as an uncomfortable ride. In lay terms, an invention is a novel device, material, or technique. ...

The motors driving the train on an MU unit are typically mounted underneath the floor of the carriages, on the bogies (in the U.S. "trucks"), the assembly beneath the train that holds the axles and wheels. Bogies This game was started by BBCs Dick and Dom as part of their hit childrens TV show, Dick and Dom in da Bungalow. ...

The driver's cab on an MU is usually truncated to a short room at both ends of the train.

Advantages of multiple units

There are several advantages of multiple units as compared to locomotive-hauled trains.

• MUs are more energy efficient than locomotive-hauled trains and more nimble, especially on grades, as much more of the entire train's weight (sometimes all of it) is placed on power-driven wheels, rather than suffer the dead weight of unpowered coaches;

• MUs have cabs at each end, so that the train may be reversed without having to uncouple/re-couple and move the locomotive, which results in far quicker turnaround times, reduced crewing costs, and enhancing safety;

• MUs may usually be quickly made up or broken up into trains of varying lengths. In a handful of applications, several multiple units may run as a single train, then be broken at a junction point into smaller trains for diverse destinations. Sometimes passage is available between the units, either for passengers or just for the train crew.

The quicker turnaround time that results, and the reduced size compared with large locomotive-hauled trains, has made the MU a major part of suburban commuter rail services in many countries. MUs are also the type of train used almost exclusively on underground railways. Great Western Railway No. ... Illustration of the backyards of a surburban neighbourhood Suburban redirects here. ... This page refers to urban rail mass transit systems. ...

Most MUs are powered either by a diesel engine driving the wheels through a gearbox (a diesel multiple unit, or DMU), or by electric motors, receiving their power through a live rail or overhead wire (an electric multiple unit or EMU). However, diesel electric multiple units (DEMUs) also exist: these have a diesel engine which drives a generator producing electricity to drive electric motors. The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas containing oxygen (usually atmospheric air), rather than a separate source of ignition... A diesel multiple unit can be: a multiple unit powered by a diesel engine; one or more of these form a passenger train; a combination of diesel powered locomotives operating under the control of one engine-driver, coupled together consecutively, usually at the head end of the train, which further... Electric motors of various sizes. ... Third rail at Bostons South Station A third rail is a method of providing electricity to power a railroad, typically a mass transit system. ... An electric multiple unit pulling into Tile Hill station; Coventry, England. ...

Some well known examples of multiple units are the last generation German ICE and most Dutch passenger trains. Icicles A natural ice block in Iceland Ice is the solid form of water. ... Trains in the Netherlands Types of trains There are two types of double decker trains: the DDM (Dubbeldeks Materieel, see picture) train, consisting of one or more combinations of 3 or 4 coaches; there are two varieties: without motors, coupled to an electric locomotive; the mDDM: one of the coaches...

North America

Most long-distance trains in North America are locomotive-hauled, but commuter, subway, and light rail operations use extensive use of MUs. Most electrically-powered trains are MUs, although there are some major exceptions: Amtrak trains on the Northeast Corridor, the busiest passenger rail line in the U.S., are drawn by electric locomotives; New Jersey Transit service on the same line is split between electric locomotives and electric MUs. DMUs are less common, partly because new light rail operations are almost entirely electric, but DMUs are being tried on the River Line in New Jersey, and there are efforts to develop effective passenger DMUs for inter-city trains. NJ Transit has also experimented with DMUs on the Princeton Branch line. This article describes subways as mass transit lines. ... This article is about light rail systems in general. ... For the agglomeration of metropolitan areas, see article on BosWash megalopolis The Northeast Corridor (NEC) is an electrified railway line with overhead wires running from Washington, DC to Boston, Massachusetts, passing through Baltimore, Maryland, Wilmington, Delaware, Philadelphia, Pennsylvania, New York, New York, New Haven, Connecticut and Providence, Rhode Island. ... New Jersey Transit Arrow III at West Windsor, NJ Hudson-Bergen Light Rail vehicle at 2nd Street station New Jersey Transit (NJ Transit) is a statewide public transportation system serving the U.S. state of New Jersey. ... New Jersey Transit Arrow III at West Windsor, NJ Hudson-Bergen Light Rail vehicle at 2nd Street station New Jersey Transit (NJ Transit) is a statewide public transportation system serving the U.S. state of New Jersey. ... Princeton Station at night, August 2004 The Princeton Branch is a branch off of New Jersey Transits Northeast Corridor Line. ...

See also

• Push-pull (mode of operation for locomotive-hauled trains)
• Rail terminology
• Multiple-unit train control