Multiple unit trains |
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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.
The diesel engine may be located above the frame in an engine bay or under the floor. Driving controls can be at both ends, on one end, or in a separate car.
DMUs are usually classified by the method of transmitting motive power to their wheels.[ citation needed ]
In a diesel–mechanical multiple unit (DMMU), the rotating energy of the engine is transmitted via a gearbox and driveshaft directly to the wheels of the train, like a car. The transmissions can be shifted manually by the driver, as in the great majority of first-generation British Rail DMUs, but in most applications, gears are changed automatically.
In a diesel–hydraulic multiple unit (DHMU), a hydraulic torque converter, a type of fluid coupling, acts as the transmission medium for the motive power of the diesel engine to turn the wheels. Some units feature a hybrid mix of hydraulic and mechanical transmissions, usually reverting to the latter at higher operating speeds as this decreases engine RPM and noise.
In a diesel–electric multiple unit (DEMU), a diesel engine drives an electrical generator or an alternator which produces electrical energy. The generated current is then fed to electric traction motors on the wheels or bogies in the same way as a conventional diesel–electric locomotive. [1]
On some DEMUs, such as the Bombardier Voyager, each car is entirely self-contained and has its own engine, generator and electric motors. [1] In other designs, such as the British Rail Class 207 or the Stadler GTW and Stadler FLIRT DMU, [2] some cars within the consist may be entirely unpowered or only feature electric motors, obtaining electric current from other cars in the consist which have a generator and engine.
With diesel–electric transmission, some DMU can be no other than an EMU without pantograph or contact shoes (for use on the former British Rail Southern Region), which "is substituted" by one or more on-board diesel generators; this kind of DEMU can be potentially upgraded to electro-diesel multiple unit (EDMU), becoming a bi-mode multiple units train (BMU), just adding one or two pantographs or contact shoes (with opportune converters,[ clarification needed ] if necessary) and related modifications on the electric system.[ citation needed ]
NMBS/SNCB uses its NMBS/SNCB Class 41 DMUs on the few remaining unelectrified lines. As electrification progresses, the DMUs become less and less important.
Diesel multiple units cover large number of passenger lines in Croatia which are operated by the national passenger service operator HŽ Putnički Prijevoz. On Croatian Railways, DMUs have important role since they cover local, regional and distant lines all across the country. The country's two largest towns, Zagreb and Split, are connected with an inter-city service that is provided by DMU tilting trains "RegioSwinger" (Croatian series 7123) since 2004. Those trains may also cover other lines in the country depending on need and availability.
Luxury DMU series 7021, built in France, started to operate for Yugoslav Railways in 1972 and after 1991 still remained in service of Croatian Railways until 2005. Units 7121 and 7122 (which came as a replacement for 7221 units), together with the newest series 7022 and 7023 built in 2010s Croatia, cover many of the country's local and regional services on unelectrified or partly electrified lines.
Diesel multiple units also cover large number of passenger lines in the Czech Republic which are operated by the national operator České dráhy. They have important role since they cover local, regional and distant lines all across the country. Those trains may also cover other lines in the country depending on need and availability too.
Also, the DMUs were manufactured for foreign carriers. The tables of cars and units are divided into vehicles operated until 1987, when the ČSD used the series designations proposed by Vojtěch Kryšpín, and vehicles created after this date, which no longer have Kryšpín's designations (with some exceptions). In addition, these new cars are the new vehicles are already different in both countries.
Elron has since 2015 a Stadler FLIRT fleet, with 20 trains DEMU version.
Germany has employed DMUs for both commuter and express services for many decades. The SVT 877 Fliegender Hamburger DMU, introduced in 1933, made the run from Berlin to Hamburg in an astonishing 138 minutes, and its derivative SVT 137 broke the land speed record in 1936. After World War 2, the VT 11.5 DMU was the flagship of the glamorous Trans Europ Express.
Since 1968, DB has designated DMUs with class numbers beginning in 6. While DB and regional transport authorities generally prefer electric power for commuter rail, many local and rural lines remain un-electrified, and DMUs are invaluable in providing services to those areas. DMUs in service as of 2021 include the Adtranz Class 612 tilting train ("Regio Swinger"), the Alstom Coradia LINT (Classes 620–623, 640 and 648), the Siemens Desiro (Class 642) and the Bombardier Talent (Class 643/644). From 2001 to 2016 there was even a DMU version of DB's high-speed Intercity Express, the Class 605 ICE TD.
In the Republic of Ireland the Córas Iompair Éireann (CIÉ), which controlled the republic's railways between 1945 and 1986, introduced DMUs in the mid-1950s and they were the first diesel trains on many main lines. [3]
DMUs are used mostly on shorter or less frequently travelled routes in remote areas. The national railway company CFR still uses, along with other DMU models, Class 77 and 78 DMUs, locally built by Malaxa between the 1930s and 50s and refurbished in the 70s. The main DMU in use is the Class 96 Siemens Desiro aka Săgeata Albastră (The Blue Arrow). Private operators also largely use DMU units, mainly purchased from various French and German operators.
In the present, several types of DMUs operate in Slovakia. Was the most common type in Slovakia is a Class 812 ZSSK based on the ČD Class 810. These are used almost exclusively for hauling passenger trains on non-electrified regional lines and these trains often excel in low travel speeds. In the past, however, in Slovakia there were a number of express trains driven by motor coaches, which often overcame heavier trains driven by steam locomotives at cruising speed, and classic sets. A typical example can be, for example, the Slovenská strela motor express train led on the Bratislava-Prague route by a motor car of the same name, or the Tatran express from Bratislava to Košice. Representatives of high-speed motor wagons were, for example, motor wagons of the M262 or M286 series, which, however, lost their application in high-speed wagons due to the gradual electrification of main lines and were, like the current wagons currently used for passenger trains.
The first significant use of DMUs in the United Kingdom was by the Great Western Railway, which introduced its small but successful series of diesel–mechanical GWR railcars in 1934. The London & North Eastern Railway [4] and London, Midland & Scottish Railway also experimented with DMUs in the 1930s, the LMS both on its own system, and on that of its Northern Irish subsidiary, but development was curtailed by World War II.
After nationalisation, British Railways (BR) revived the concept in the early 1950s. At that time there was an urgent need to move away from expensive steam traction which led to many experimental designs using diesel propulsion and multiple units. The early DMUs proved successful, and under BR's 1955 Modernisation Plan the building of a large fleet was authorised. These BR "First Generation" DMUs were built between 1956 and 1963.
BR required that contracts for the design and manufacture of new locomotives and rolling stock be split between numerous private firms as well as BR's own workshops, while different BR Regions laid down different specifications. The result was a multitude of different types, one of which was:
In 1960, British Railways introduced its Blue Pullman high-speed DEMUs. [5] These were few in number and relatively short-lived, [5] but they paved the way for the very successful InterCity 125 or High Speed Train (HST) units, which were built between 1975 and 1982 to take over most principal express services on non-electrified routes. [6] [7] These 125 mph (201 km/h) trains run with a streamlined power car at each end and (typically) seven to nine intermediate trailer cars. [8] [9] Although originally classified as DEMUs, the trailer cars are very similar to loco-hauled stock, and the power cars were later reclassified as locomotives under Class 43. [8] [9] HSTs started being replaced in 2017, but as of October 2022 some are still in use. [10] [11]
By the early 1980s, many of the surviving First Generation units were reaching the end of their design life, leading to spiralling maintenance costs, poor reliability and a poor public image for the railway. A stopgap solution was to convert some services back to locomotive haulage, as spare locomotives and hauled coaching stock were available, but this also increased operating costs. Commencing in the mid '80s, British Rail embarked upon its so called "Sprinterisation" programme, to replace most of the first generation DMUs and many locomotive-hauled trains with three new families of DMU:
Following the impact of the privatisation of British Rail in the late 1990s, several other DMU families have been introduced:[ citation needed ]
In 2018, the first bi and tri-mode electro-diesel multiple units were introduced:
Canada generally follows similar buffer strength requirements to the US, [19] but new services are evaluated on a case-by-case basis. As a result, several types of lightweight DMUs have been used:
Costa Rica has purchased several Apolo 2400 series DMU railcars from the former narrow gauge operator in Spain, which are run in commuter service. [21]
42 X'Trapolis Tsíimin K'áak train sets have been ordered for Tren Maya, 10 of which are DMU and 32 are EDMU. [22]
A type of diesel multiple units in the U.S. was the Budd Rail Diesel Car (RDC). The RDC was a single passenger car with two diesel engines and two sets of controls. [23]
In the United States, DMU systems must be FRA-compliant to be permitted on freight rail corridors. The Federal Railway Administration has mandated higher coupling strength requirements than European regulators, effectively prohibiting the use of lighter weight European-style inter-city rail DMUs on U.S. main line railways without timesharing with freight operations or special waivers from the FRA. This has greatly restricted the development of DMUs within the U.S. as no other country requires the much heavier FRA compliant vehicles, and no export market for them exists. [24]
Operations using FRA-compliant vehicles:
Operations using non FRA-compliant vehicles:
Proposed operations:
DMUs were first introduced to Australia in the late mid-20th century for use on quiet branch lines that could not justify a locomotive hauled service. Today, DMUs are widely used throughout Australia's southern states:
In Queensland, heritage DMUs are used on the Savannahlander and Gulflander tourist trains.
Chinese manufactured (CNR Tangshan) DEMU was introduced in Bangladesh from 25 May 2013. DEMU is the country's first-ever commuter train service starting its journey on the Chittagong–Fouzdarhat line. These DEMUs also operate on the Chittagong Circular Railway and on the Bangladesh Railway's service between Dhaka and Narayanganj. [36]
Mexican manufacturer Ferrovias Del Bajio supplied in 2019, three DSUs (Diesel Single Unit) to Royal Railway in Cambodia for their airport shuttle service from Phnom Penh international airport to the city central station. The other two units were assigned to long-distance services from the central station to Sihanoukville and to Poipet. Royal Railways Cambodia have now acquired eleven carriages DMU from Japan. Model: " Kiha 183 heavy snow ". (キハ183系オホーツク・大雪) Speed: 110 km/h (max) Type: 特急 (Limited Express) Started: 1986 ............ End of Service in Japan 17 March 2023
DMUs (DEMUs) are widely used in India. DEMUs in India are used in both the eight-coach format and the four-coach format. These trains replaced many (up to 10 car) trains with a WDM-2 or WDM-3A locomotive in the middle. These old trains had the loco controls duplicated in the Driving Trailer coach and all the actuation information reaching the locomotive through thin communication lines. This was called 'push-pull train'. The longest running such push-pull service operated between Diva – Bhiwandi Road and Vasai Road and was recently converted into an MEMU train service in 2018.
India's first and largest DMU shed at Jalandhar, Punjab, holds more than 90 units placed in service all over Punjab. First generation DMU: Rated power was 700 HP and had three or six coaches, made first by ICF. Transmission was Voith-hydraulic. Max speed 100 km/h.
Second generation DMU: Rated power is 1400 HP and have eight coaches. Max speed is 105 km/h. Transmission is DC electric. Made at ICF and RCF.
Third generation DMU: Rated power is 1,600 HP and have ten coaches. Max speed is 110 km/h. Transmission is AC electric. Made at ICF.
State-owned company PT.INKA builds several type of DMU, some of which operate in urban and suburban areas.
In Japan, where gasoline-driven railbuses (on small private lines) and railmotors (Kihani 5000 of the national railways) had been built since the 1920s, the first two streamlined DMUs came in service in 1937, class Kiha 43000 (キハ43000系). [37]
The service of several hundreds (in sum even thousands) of diesel railcars and DMUs started in 1950s following the improvement of fuel supply that was critical during World War II. [38]
In 2021, Kenya acquired DMUs from France to operate in the Nairobi Metropolitan Area. These trains connect the city with settlements outside Nairobi, Jomo Kenyatta International Airport and the Nairobi Terminus.
The Keretapi Tanah Melayu (KTM) has a total of 13 DMU KTM Class 61 ordered from CRRC for the West Coast Line and are assembled locally at CRRCs Batu Gajah factory from 2016 to 2020. The first scheduled service is expected from 1 September along the Gemas-Johor Bahru route, replacing old non-automotive stock. [39]
The Philippine National Railways (PNR) was one of the first adopters of diesel multiple unit trains in Asia. Initially built as gasoline-powered railmotors, the locally assembled Manila Railroad RMC class of 1929 was the first to be powered by diesel traction. Some units were also converted to streamliner units by 1932 for first-class services on the South Main Line between Manila and Legazpi, Albay. [40] Since then, generations of DMUs were used chiefly for short-distance commuter services by the PNR in the island of Luzon. [41] [42]
Even without active inter-city rail services in the present-day, DMUs are still used on the PNR Metro Commuter Line in Metro Manila and the Bicol Commuter service in the Bicol Region. [43] Three generations of DMUs are in use: second-hand DMUs handed over by JR East such as the KiHa 35, 52 and 59 series originally built in the 1960s and acquired in the early 2010s, [44] [45] the Rotem DMUs of 2009 built by Korean manufacturer Hyundai Rotem, [46] and the 8000 and 8100 classes built by Indonesian firm PT INKA. [47] [48]
From 2022 onwards, the PNR will purchase standard gauge DMUs for its upcoming inter-city rail network in Luzon and Mindanao. This is compared to the 3 ft 6 in gauge of the rolling stock that is currently in active service. This move should allow access to better technology and increase line speeds.
On 14 January 2014, CRRC Changchun Railway Vehicles announced that hybrid electric multiple units were put into production. At the end of 2014, the first batch of hybrid EMUs, one train each with battery-catenary power supply (EEMU) and catenary power supply-internal combustion engine (DEMU), rolled off the assembly line in Changchun. From 2016 to 2020, the vehicles were tested in Hohhot and Beijing Academy of Railway Sciences.
In September 2022, the first CJ-5 train used by the Xi'an-Huxian Railway arrived in Xi'an. The No. 0506 train, which uses an internal combustion engine and a battery hybrid, was used as a vehicle during the initial operation of the Xi'an-Huxian Railway. During the operation period, it will be temporarily managed by Xi'an Metro.
Korail used to operates many DMUs. The DHC (Diesel Hydraulic Car), which made its debut for the 1988 Seoul Olympics, was able to reach speeds up to 150 km/h (93 mph) and served Saemaul-ho trains. These train have retired on 2008.[ citation needed ]
DMUs were first introduced to Sri Lanka in 1940. The aim of this was connecting minor railway stations and stops on the main line where most express trains don't have a halt. [49]
The DMUs are now usually used on the Taiwan Railway Administration Hualien–Taitung Line, North-Link Line, South-Link Line. DMUs in Taiwan are classified as Class DR.
Thailand
The State Railway of Thailand ASR class is a diesel multiple unit operated by the State Railway of Thailand. Built by British Rail Engineering Limited at Derby Litchurch Lane Works in England, it is based on the British Rail Class 158. Twenty carriages were built in 1990/91. All were painted in the same Regional Railways livery as the Class 158s.
DMU manufacturers include:
A multiple-unit train is a self-propelled train composed of one or more carriages joined, and where one or more of the carriages have the means of propulsion built in. By contrast, a locomotive-hauled train has all of the carriages unpowered.
A railcar is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach, with a driver's cab at one or both ends. Some railway companies, such as the Great Western, termed such vehicles "railmotors".
The Siemens Desiro is a family of diesel or electric multiple unit passenger trains developed by Siemens Mobility, a division of the German Siemens AG conglomerate. The main variants are the Desiro Classic, Desiro ML, Desiro UK and the later Desiro City, Desiro HC and Desiro RUS. The trains are mostly used for commuter and regional services, and their rapid acceleration makes them suitable for services with short distances between stations. The design is flexible, and has become common in many European countries.
Vygruppen, branded as Vy, formerly the Norwegian State Railways, is a government-owned railway company which operates most passenger train services and many bus services in Norway. The company is owned by the Norwegian Ministry of Transport. Its sub-brands include Vy Buss coach services, CargoNet freight trains and the Swedish train transport company Tågkompaniet. In 2009, NSB carried 52 million train passengers and 104 million bus passengers. On 24 April 2019, passenger train and bus services were rebranded as Vy.
A bilevel car or double-decker coach is a type of rail car that has two levels of passenger accommodation as opposed to one, increasing passenger capacity.
A railbus is a lightweight passenger railcar with an automotive engine. It shares many aspects of its construction with a bus, typically having a bus body and four wheels on a fixed base instead of on bogies. Originally designed and developed during the 1930s, railbuses have evolved into larger dimensions with characteristics similar in appearance to a light railcar, with the terms railcar and railbus often used interchangeably. Railbuses designed for use specifically on little-used railway lines were commonly employed in countries such as Germany, Italy, France, the United Kingdom, and Sweden.
The British Rail Class 104 diesel multiple units were built by Birmingham Railway Carriage and Wagon Company from 1957 to 1959.
The British Rail Classes 101 and 102 diesel-mechanical multiple units were built by Metro-Cammell at Washwood Heath in Birmingham, England, from 1956 to 1959, following construction of a series of prototype units. These classes proved to be some of the most successful and longest-lived of BR's First Generation DMUs, second in longevity only to the Class 121, with the final five units being withdrawn on 24 December 2003. The oldest set was, by then, just over 47 years old.
The British Rail Class 127 diesel multiple units were built by BR Derby in 1959. Thirty 4-car units were built, formed of two outer driving motor vehicles, sandwiching two intermediate trailers which were classified class 186. The technical description of such as 4-car unit was DMBS + TSL + TS + DMBS.
The Budd Rail Diesel Car (RDC), also known as the Budd car or Buddliner, is a self-propelled diesel multiple unit (DMU) railcar. Between 1949 and 1962, 398 RDCs were built by the Budd Company of Philadelphia, Pennsylvania, United States. The cars were primarily adopted for passenger service in rural areas with low traffic density or in short-haul commuter service, and were less expensive to operate in this context than a traditional diesel locomotive-drawn train with coaches. The cars could be used singly or coupled together in train sets and controlled from the cab of the front unit. The RDC was one of the few DMU trains to achieve commercial success in North America. RDC trains were an early example of self-contained diesel multiple unit trains, an arrangement now in common use by railways all over the world.
An electro-diesel locomotive is a type of locomotive that can be powered either from an electricity supply or by using the onboard diesel engine. For the most part, these locomotives are built to serve regional, niche markets with a very specific purpose.
Push–pull is a configuration for locomotive-hauled trains, allowing them to be driven from either end of the train, whether having a locomotive at each end or not.
The Stadler GTW is an articulated railcar for local transport made by Stadler Rail of Switzerland. GTW stands for Gelenktriebwagen.
A control car, cab car, control trailer, or driving trailer is a non-powered rail vehicle from which a train can be operated. As dedicated vehicles or regular passenger cars, they have one or two driver compartments with all the controls and gauges required to remotely operate the locomotive, including exterior locomotive equipment such as horns, bells, ploughs, and lights. They also have communications and safety systems such as GSM-R or European Train Control System (ETCS). Control cars enable push-pull operation when located on the end of a train opposite its locomotive by allowing the train to reverse direction at a terminus without moving the locomotive or turning the train around.
The British Rail Class 125 was a design of three car Diesel Multiple Unit built by BR Derby at Derby Works in 1958. They were almost identical in appearance to the Class 116.
Stadler FLIRT is a passenger multiple unit trainset made by Stadler Rail of Switzerland. The baseline design of FLIRT is an electric multiple unit articulated trainset that can come in units of two to twelve cars with two to six motorized axles. The maximum speed is 200 km/h (125 mph). Standard floor height is 57 cm, but 78 cm high floors are also available for platform heights of 76 cm.
Diesel multiple units and railcars are trains, usually with passenger accommodation, that do not require a locomotive. Railcars can be single cars, while in multiple units cars are marshalled together with a driving position either end. As of December 2010, 23 percent of the rail passenger cars used on Network Rail are part of a diesel multiple unit.
An electro-diesel multiple unit (EDMU) or bi-mode multiple unit (BMU) is a form of a multiple unit train that can be powered either by electric power picked up from the overhead lines or third rail or by using an onboard diesel engine, driving an electric generator, which produces alternating current (AC) or direct current (DC) electric power.
A multiple-unit train or simply multiple unit (MU) is a self-propelled train composed of one or more carriages joined together, which when coupled to another multiple unit can be controlled by a single driver, with multiple-unit train control. Although multiple units consist of several carriages, single self-propelled carriages, such as railbuses and trams – are in fact multiple-units when two or more of them are working connected through multiple-unit train control.
In the Voyager application, every car has a Cummins underfloor engine and alternator supplying power to a pair of body-mounted traction motors. Each drives one inner axle through a cardan shaft and axle-mounted final drive gearbox.