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Train

Train

:For other types of train see train (disambiguation) 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. The guideway (permanent way) usually consists of conventional rail tracks, but might also be monorail or maglev. Propulsion for the train is typically provided by a separate locomotive, or from individual motors in self-propelled multiple units. Power is usually derived from diesel engines or from electricity supplied by trackside systems. Historically the steam engine was the dominant form of locomotive power, and other sources of power (such as horses, pneumatics, or gas turbines) are possible as well. In American railway terminology, a consist is used to describe the group of rail vehicles which make up a train.

Types of trains

railway terminology, Perth ]] There are various types of trains designed for particular purposes, see rail transport operations. A train can consist of a combination of a locomotive and attached railroad cars, or a self-propelled multiple unit (or occasionally a single powered coach, called a railcar). Trains can also be hauled by horses, pulled by a cable, or run downhill by gravity. Special kinds of trains running on corresponding special 'railways' are atmospheric railways, monorails, high-speed railways, Dinky Trains, maglev, rubber-tired underground, funicular and cog railways. cog railway A passenger train may consist of one or several locomotives, and one or more coaches. Alternatively, a train may consist entirely of passenger carrying coaches, some or all of which are powered as a "multiple unit". In many parts of the world, particularly Japan and Europe, high-speed rail is utilized extensively for passenger travel. Freight trains comprise wagons or trucks rather than carriages, though some parcel and mail trains (especially Travelling Post Offices) are outwardly more like passenger trains. In the United Kingdom, a train hauled by two locomotives is said to be "double-headed", and in Canada and the United States it is quite common for a long freight train to be headed by three, four, or even five locomotives. Trains can also be mixed, hauling both passengers and freight, see e.g. Transportation in Mauritania. Such mixed trains became rare in many countries, but were commonplace on the first 19th-century railroads. Special trains are also used for track maintenance; in some places, this is called maintenance of way. A single uncoupled rail vehicle is not technically a train, but is usually referred to as such for signaling reasons.

Motive power

maintenance of way] The first trains were rope-hauled or pulled by horses, but from the early 19th century almost all were powered by steam locomotives. From the 1920s onwards they began to be replaced by less labor intensive and cleaner (but more expensive) diesel locomotives and electric locomotives, while at about the same time self-propelled multiple unit vehicles of either power system became much more common in passenger service. Most countries had replaced steam locomotives for day-to-day use by the 1970s. A few countries, most notably the People's Republic of China where coal is in cheap and plentiful supply, still use steam locomotives, but this is being gradually phased out. Historic steam trains still run in many other countries, for the leisure and enthusiast market. coal Electric traction offers a lower cost per mile of train operation but at a very high initial cost, which can only be justified on high traffic lines. Since the cost per mile of construction is much higher, electric traction is less favored on long-distance lines. Electric trains receive their current via overhead lines or through a third rail electric system.

Passenger trains

Passenger trains have Passenger cars. Passenger trains travel between stations; the distance between stations may vary from under 1 km to much more. Long-distance trains, sometimes crossing several countries, may have a dining or restaurant car; they may also have sleeping cars, but not in the case of high-speed rail, these arrive at their destination before the night falls and are in competition with airplanes in speed. Very long distance trains such as those on the Trans-Siberian railway are usually not high-speed. Very fast trains sometimes tilt, like the Pendolino or Talgo. Tilting is a system where the passenger cars automatically lean into curves, reducing the centrifugal forces acting on passengers and permitting higher speeds on curves in the track with greater passenger comfort. For trains connecting cities, we can distinguish inter-city trains, which do not halt at small stations, and trains that serve all stations, usually known as local trains or "stoppers" (and sometimes an intermediate kind, see also limited-stop). limited-stop For shorter distances many cities have networks of commuter trains, serving the city and its suburbs. Some carriages may be laid out to have more standing room than seats, or to facilitate the carrying of prams, cycles or wheelchairs. Some countries have some double-decked passenger trains for use in conurbations. Double deck high speed and sleeper trains are becoming more common in Europe. Passenger trains usually have emergency brake handles (or a "communication cord") that the public can operate. Abuse is punished by a fine. fine Large cities often have a metro system, also called underground, subway or tube. The trains are electrically powered, usually by third rail, and their railroads are separate from other traffic, without level crossings. Usually they run in tunnels in the city center and sometimes on elevated structures in the outer parts of the city. They can accelerate and decelerate faster than heavier, long-distance trains. A light one- or two-car rail vehicle running through the streets is not called a train but a tram, trolley, light rail vehicle or streetcar, but the distinction is not strict. The term light rail is sometimes used for a modern tram, but it may also mean an intermediate form between a tram and a train, similar to metro except that it may have level crossings. These are often protected with crossing gates. They may also be called a trolley. Maglev trains and monorails represent minor technologies in the train field. The term rapid transit is used for public transport such as commuter trains, metro and light rail. However, in New York City, lines on the New York City Subway have been referred to as "trains".

Freight trains

Passenger train human waste disposal Freight trains have freight cars. Much of the world's freight is transported by train. In the USA the rail system is used mostly for transporting freight (or cargo). Under the right circumstances, transporting freight by train is highly economic, and also more energy efficient than transporting freight by road. Rail freight is most economic when freight is being carried in bulk and over long distances, but is less suited to short distances and small loads. The main disadvantage of rail freight is its lack of flexibility. For this reason, rail has lost much of the freight business to road competition. Many governments are now trying to encourage more freight onto trains, because of the environmental benefits that it would bring. road competition]] There are many different types of freight train, which are used to carry many different kinds of freight, with many different types of wagon. One of the most common types on modern railways are container trains, whereby the containers can be lifted on and off the train by cranes and loaded off or onto trucks or ships. ship in 1992.]] This type of freight train has largely superseded the traditional "box wagon" type of freight train, whereby the cargo had to be loaded or unloaded manually. In some countries "piggy back" trains are used whereby trucks can drive straight onto the train and drive off again when the end destination is reached. A system like this is used on the Channel Tunnel between England and France. Piggy back trains are the fastest growing type of freight trains in the United States, where they are also known as 'trailer on flat car' or TOFC trains. There are also some "inter-modal" vehicles, which have two sets of wheels, for use in a train, or as the trailer of a road vehicle. There are also many other types of wagon, such as "low loader" wagons for transporting road vehicles. There are refrigerator wagons for transporting food. There are simple types of open-topped wagons for transporting minerals and bulk material such as coal and tankers for tranporting liquids and gases. Freight trains are sometimes illegally boarded by passengers who do not wish, or do not have the money, to travel by ordinary means. This is referred to as "Hopping" and is considered by some communities to be a viable form of transport. Most hoppers sneak into train yards and stow away in boxcars. More bold hoppers will catch a train "on the fly", that is, as it is moving, leading to occasional fatalities, some of which go unrecorded.

Famous train routes

Main article: Famous trains Famous historical train services include the:
- Orient Express in Europe.
- Trans-Siberian in Russia.
- Blue Train in South Africa.
- Train-de-Luxe from Johannesburg to Victoria Falls.
- Chihuahua al Pacifico in Mexico.
- Palace on Wheels in Rajasthan, India.
- Frontier Mail and Grand Trunk Express, India.
- The Canadian in Canada.
- 20th Century Limited in the USA.
- City of New Orleans in the USA.
- California Zephyr in the USA.
- The Indian-Pacific and The Ghan in Australia (long-distance rail).
- Puffing Billy and The Gulflander in Australia (heritage and touring).
- Rheingold Express in The Netherlands, Germany and Switzerland, following the course of the Rhine.

Fictional trains

See also: Rail transport in fiction
- Hogwarts Express — Takes Harry Potter to Hogwarts Academy.
- Taggart Comet (Atlas Shrugged)
- The Great Train Robbery — feature film based on a true story, also title of a modern film.
- Starlight Express (Andrew Lloyd Webber) — Musical about an old steam engine being replaced by an electrical engine.
- Galaxy Express 999 — From the manga and anime of the same name by Leiji Matsumoto, this train travels the galaxy from planet to planet.
- The Polar Express — From the book of the same name, this train takes children to the North Pole.
- Runaway Train — Film about escaped inmates on a runaway train.
- Atomic Train — TV movie (1999) A runaway train carrying an atomic bomb into a town.
- Thomas the Tank Engine and Friends TV Series originated from The Railway Series by the Rev.W.Awdry For a list of railway movies, see [http://www.spikesys.com/Trains/rly_movs.html] (website last updated December 5, 1995).

External links

- [http://www.raileurope.co.uk Book European rail travel online]
- [http://www.railfaneurope.net High Speed Train]
- Official [http://ojp.nationalrail.co.uk/planmyjourney/time_table/journey_requirements.asp train times] in the UK (from [http://www.nationalrail.co.uk/ National Rail]).
- [http://www.railserve.com/ RailServe.com: The Internet Railroad Directory] - directory of 10,000 train sites
- [http://www.trainfoamers.com Trainfoamers.com] - It's Free To Talk Trains Again!
- [http://www.trainorders.com Trainorders.com] - Focus on trains of North America Category:Vehicles Category:Rail transport ms:Keretapi ja:列車

Train (disambiguation)

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. Train may also mean:
- Train (roller coaster), the specialized vehicle which transports riders around a roller coaster track
- camel train or wagon train, an animal-powered transport caravan
- In mining, a train is another term for a conveyor, normally a conveyor belt
- A road train, utilises road vehicles to carry freight
- trackless train, running on roads, looks like a train is often used for amusement
- bridal train on a wedding dress, more generally in clothing, a train refers to the part of a some gowns that trail behind the wearer
- A sperm train is a (slightly controversial) theory that sperm move together.
- Train (band), an American modern rock band formed in 1994
- Tourist Railway Association, Inc., acronym TRAIN
- Train 48, a Canadian drama series which ran from 2003 until 2005

Permanent Way

Permanent Way is a term used collectively to describe the track infrastructure of a railway, ie. the rails, sleepers, trackbed, bridges, water drainage, etc. The Permanent Way Institution is a specialist society interested in the dissemination of Permanent Way knowledge and techniques amongst interested parties at all levels from the trackmen to the civil engineers. It was founded in 1884 and now has over 7500 members throughout the Commonwealth. See also: Rolling stock Category:Rail transport

Rail tracks

Railroad or railway tracks are used on railways, which, together with railroad switches (points), guide trains without the need for steering. Tracks consist of two parallel steel rails, which are laid upon sleepers (or cross ties) which are embedded in ballast to form the railroad track. The rail is fastened to the sleepers with rail spikes for wooden sleepers or Pandrol clips for cement or concrete sleepers. Rails, being made of steel, can carry heavier loads than any other material. Sleepers spread the load from the rails over the ground, and also serve to hold the rails a fixed distance apart (called the gauge). Rail tracks are normally laid on a bed of coarse stone chippings known as ballast, which combines resilience, some amount of flexibility, and good drainage; however, track can also be laid on or into concrete (this is called slab track). Across bridges track is often laid on sleepers across longitudinal timbers.

Railway rail

Unlike other uses of iron and steel, railway rails are subject to very high stresses and have to be made of very high quality steel. It took many decades to improve the quality of the materials, including the change from iron to steel. Minor flaws in the steel that pose no problems with, say, reinforcing rods for buildings, can lead to broken rails and dangerous derailments when used on railway tracks. The rails represent a substantial fraction of the cost of a railway line. Only a small number of rail sizes are made by the steelworks at the one time, so a railway must choose the nearest suitable size. Worn heavy rail from a mainline is often cascaded to branchline use. Rails are made in a large number of different sizes. Some common European rail sizes include:
- 40 kg/m (81 lb/yd)
- 50 kg/m (101 lb/yd)
- 60 kg/m (121 lb/yd) Some common North American rail sizes include:
- 115 lb/yd (57 kg/m)
- 133 lb/yd (66 kg/m)
- 136 lb/yd (67 kg/m)
- 140 lb/yd (69 kg/m) Rails in Canada, the United Kingdom, and United States are still described using imperial units. The examples in the diagram opposite are 113 and 95 pounds per yard (56 kg/m and 47 kg/m) respectively. Early railroads sometimes used strap-iron rails, which consisted of thin strips of iron strapped onto wooden rails. These rails were too fragile to carry heavy loads, but because the initial construction cost was less, this method was sometimes used to quickly build an inexpensive rail line. However, the long term expense involved in frequent maintenance outweighed any savings.

Axle load

By and large, the heavier the rails and the rest of the track, the heavier and faster the trains on those tracks can be.

Jointed track

Axle load There are different ways of joining rails together to form tracks. The traditional way of doing this was to bolt rails together in what is known as jointed track. In this form of track, lengths of rail, usually around 20 metres (60 feet) long, are laid and fixed to sleepers (U.K.) (crossties, or simply ties in North American practice), and are joined to other lengths of rail with steel plates known as fishplates (U.K.) or joint bars (N.A.). Historically, North American railroads until the mid to late 20th century used sections of rail that measured 39 feet (11.9 m) long so they could be carried to and from a worksite in conventional gondolas, which often measured 40 feet (12.2 m) long; as car sizes increased, so did rail lengths. Fishplates or joint bars are usually 60 centimetres (2 feet) long, and are bolted through each side of the rail ends with bolts (usually four, but sometimes up to six). Small gaps are deliberately left between the rails, which are known as "expansion joints" to allow for expansion of the rails in hot weather. The holes through which the fishplate bolts pass are oval to allow for expansion. British practice was always to have the rail joints on both rails at the same place on each rail, while North American practice is to stagger them. Because of the small gaps left between the rails, when trains pass over jointed tracks they make a "clickety clack, clickety clack" noise. Unless it is very well maintained, jointed track gives a fairly bumpy and uncomfortable ride, and is unsuitable for high speed trains because it is too weak. However it is still used in many countries on lower speed lines, unimportant lines, and sidings. Most railroad track in the United States is still of this type, however, and laid on timber ties; the lower speeds of American railroads make the disadvantages less apparent, and the abundant supply of timber in the United States makes its use for railroad ties much cheaper than in Europe. Jointed track is still extensively used in poorer countries, due to the cheaper construction costs and lack of modernisation of their railway systems.

Continuous welded rail

siding Most modern railways use continuous welded rail (CWR); in this form of track the rails are welded together, by utilising the thermite reaction, to form one continuous rail that may be several kilometres long. Because there are few joints, this form of track is very strong, gives a smooth ride, and needs less maintenance. Because of its strength, trains travelling on welded track can travel at higher speeds and with less friction. Welded rails are more expensive to lay than jointed tracks, but are significantly cheaper to maintain. As mentioned earlier, rails expand in hot weather and shrink in cold weather. Because welded track has very few expansion joints, if no special measures are taken, it could become distorted in hot weather and cause a derailment. To avoid this happening welded rails are very often laid on concrete sleepers, which are so heavy they hold the rails firmly in place, and with plenty of ballast to stop the sleepers moving. After new segments of rail are laid, or defective rails replaced (welded in), the rails are artificially heated so that they expand (this is called stressing), they are then fastened (clipped) to the sleepers in their expanded form. This ensures that the rail will not expand much further in subsequent hot weather, and because they are firmly fastened, cannot shrink in cold weather either. However if temperatures reach outside normal ranges (i.e. a hotter than usual summer), welded rails can become distorted. Joints are used in continuously welded rail when necessary; instead of a joint that passes straight across the rail, producing a loud noise and shock when the wheels pass over it, two sections of rail are cut at a steep angle and put together with a gap between them (a breather switch). This gives a much smoother transition yet still provides some expansion room.

Methods of fixing rail to sleepers/ties

breather switch There are several methods used to fasten rail to wooden sleepers / ties. In traditional British practice, cast metal chairs were screwed to the sleepers, which took a style of rail known as bullhead which was somewhat figure-8 in cross-section — wider at top and bottom (known as the head and foot respectively) and smaller in the middle (the web). Keys, which were wedges of wood or sprung steel were then driven in between chair and rail to hold it in place. The idea behind bullhead rails was that because both the top and bottom of the rails were the same shape, when one side of the rail became worn, the rail could be turned over to the unused side, thus extending the rail's lifespan. In practice, bullhead rails have a flat base (narrower than flat-bottomed rail), and the top part has curved edges which fit the profile of the train wheels. Like most of the world, Britain now uses flat-bottomed rail (Vignoles rail), which has become the worldwide standard type of rail and, as the name suggests, has a flat base and can stand upright without support. A flat-bottomed rail has a cross-section like that of an upside-down 'T' and is usually held to the sleeper with a baseplate, a metal plate attached to the sleeper, although for cheap construction they can be laid directly onto the sleepers. Vignoles Modern sleepers can be made of reinforced concrete and pressed steel, with rubber pads inserted between the sleeper and rail. This is done for two reasons: to give a smoother ride and to prevent the sleeper shorting the track circuit, a low voltage passed through the rails for signalling purposes. This is different from "traction current" which powers electric trains. A variety of different types of heavy-duty clips are used to fasten the rails to the underlying baseplate, one common one being the Pandrol fastener, named after its maker, which is shaped like a sturdy, stubby paperclip. North American practice normally uses spikes, which are fundamentally very large nails with bent-over heads to clasp the flat-bottomed rail. These are cheaper and simpler to install but can loosen if the tie rots — much more easily than the British chair does. This is mitigated by using very large and solid ties and using rot-proofing preservative. Image:Stanthorpe Rail Bridge DSC03186.jpg|Wooden Sleepers Image:Adelaide Darwin Railway Line between Adelaide River and Pine Creek DSC03643.jpg|Concrete Sleepers Image:Pine Creek Rail Steel Sleepers DSC03637.jpg|Steel Sleepers Image:Trevethick rail DSC00322.JPG|Iron & Brick Sleepers

Track maintenance

Vignoles] Track needs frequent maintenance to remain in good order, the frequency increasing with higher-speed or heavier trains. This was formerly hard manual labour, including teams of gandy dancers who used levers to force rails back into place on steep turns, correcting the gradual shifting caused by the centrifugal force of passing trains. Currently, maintenance is facilitated by a variety of specialised machines. The profile of the track is maintained using a railgrinder. Common maintenance jobs include spraying ballast with weedkiller to prevent weeds growing through and disrupting the ballast. This is typically done with a special weedkilling train. Over time, ballast is crushed by the weight of trains passing over it, and periodically it needs to be replaced. If this is not done then the tracks become uneven. Broken or worn out rails also need replacing periodically. Mainline rails that get worn out usually have life left in branchline use and are "cascaded" to those branchlines.

U.S. track classes

In the United States, the Federal Railroad Administration has developed a system of classification for track quality. The class a track is placed in determines speed limits and the ability to run passenger trains. The lowest class is referred to as excepted track. Only freight trains are allowed to operate on this type of trackage, and they may run at speeds up to 10 mph. Also, no more than five cars loaded with hazardous material may be operated within any single train. Class 1 track is the lowest class allowing the operation of passenger trains. Freight train speeds are still limited to 10 mph, and passenger trains are restricted to 15 mph. Class 2 track limits freight trains to 25 mph and passenger trains to 30 mph. Class 3 track limits freight trains to 40 mph and passenger trains to 60 mph. There is currently a legal battle between Amtrak and the Guilford Rail System over its trackage from Haverhill, MA, to Portland, ME. Amtrak is fighting for the Class 3 trackage to be used to operate its Downeaster at 79 mph. Class 4 track limits freight trains to 60 mph and passenger trains to 80 mph. Most track, especially that owned by major railroads the Union Pacific, Burlington Northern Santa Fe, CSX, and Norfolk Southern is class 4 track. Due to a technicality in law, Amtrak trains are limited to 79 mph on this track. Class 5 track limits freight trains to 80 mph and passenger trains to 90 mph. The most significant portion of Class 5 track is part of the Burlington Northern Santa Fe's Chicago–Los Angeles mainline, the old Santa Fe main, upon which Amtrak's Southwest Chief can operate at up to 90 mph. This is notable as the only area outside Amtrak-owned trackage or trackage upgraded through state funds where Amtrak trains can operate above 79 mph. Class 6 limits freight trains and passenger trains to 110 mph. Amtrak is currently working with the Iowa Interstate Railroad and the state of Illinois to upgrade a portion of its Chicago, Illinois–Kansas City, Missouri line to Class 6. Class 7 limits all trains to 125 mph. Most of Amtrak's Northeast Corridor is Class 7 trackage. Class 8 limits all trains to 160 mph. A few small lengths of the Northeast Corridor are the only Class 8 trackage in North America. Class 9 trackage limits all trains to 200 mph. There is currently no Class 9 trackage.

History

North America Some early rails were made by William Jessop in the 1790s. The steel mills making early rails often used some of the rails to build the tramways that bought iron ore and coal to those foundries. It took many decades for weak and fragile iron rails to evolve into the strong and robust steel rails of today. But problems can still occur, such as happened with the Hatfield train derailment in Great Britain on October 17, 2000. The accident involved gauge corner cracking which is now referred to as rolling contact fatigue, as the defect doesn't only occur on corners.

Magnetic levitation train

:Maglev can also mean general magnetic levitation. magnetic levitation magnetic levitation Magnetic levitation transport, or maglev, is a radically new form of transportation that suspends, guides and propels vehicles via electro-magnetic energy. Maglev technology is not “train” technology and is not compatible with conventional railroad tracks. Indeed, the science and engineering behind these ultra-safe and highly reliable ground transportation systems rivals the technological challenges once faced by America’s space program. Indeed, some high-speed maglevs (there are low-speed versions, as well) have top speeds comparable to turboprop and jet aircraft (500 – 580 km/h). It should also be emphasized that maglevs are complete transportation systems. The term maglev refers not only to the vehicles, but to the vehicle/guideway interaction; each being a unique design element specifically tailored to the other to create and precisely control magnetic levitation. The various technological approaches to maglev can be very similar or very different, depending upon the manufacturer. Due to the lack of physical contact between the track and the vehicle, the only friction exerted is that between the vehicles and the air. Consequently maglevs can potentially travel at very high speeds with reasonable energy consumption and noise levels. Systems have been proposed that operate at up to 650 km/h (404 mph), which is far faster than is practical with conventional rail transport. The very high maximum speed potential of maglevs make them competitors to airline routes of 1,000 kilometers (600 miles) or less. The world's first commercial application of a high-speed maglev line is the IOS (initial operating segment) demonstration line in Shanghai that transports people 30 km (18.6 miles) to the airport in just 7 minutes 20 seconds (top speed of 431 km/h or 268 mph, average speed 250 km/h or 150 mph). Other maglev applications worldwide are being investigated for feasibility. Recently, futurist American writer, Allan Silliphant, has proposed a fundamental model of urban metro transit that addresses the problem of going from a central point such as a city center, or an airport, to various points on the periphery of a circle around that center. Using Los Angeles, as an example, it can taken 2.5 hours to cross the city by auto. This is true of almost all great world cities. A deeply constructed maglev radial system, below any existing structures or utilites, can be bored out in virgin bedrock or undisturbed sediment. With a depth of 200 to 300 feet it would be possible to go almost anywhere in most metro areas. A transfer point in the middle will reduce the number of trains needed. Non-stop, cross metro tubes could also be constructed, next to the tube terminating in the center hub, avoiding a transfer. Present maglev speeds of even 200 miles per hour will greatly facilitate movement within an urban center. Surface maglev trains, can continue the outbound movement to the next urban center where a similar "hub and spoke" maglev deep tube system can be established. This can save many billions in fossil fuel consumption, especially if very quick access can be provided at the stations to rental cars and timely connection to public transport on the surface.

Technology

Shanghai :See also: Fundamental Technology Elements in the JR-Maglev article. :See also: Technology in the Transrapid article.

Three types of technology

There are three primary types of maglev technology:
- one that relies on superconducting magnets (electrodynamic suspension or EDS),
- one that relies on feedback controlled electromagnets (electromagnetic suspension or EMS),
- and a newer potentially more economical system that uses permanent magnets (Inductrack). Japan and Germany are active in maglev research, producing several different approaches and designs. In one design, the train can be levitated by the repulsive force of like poles or the attractive force of opposite poles of magnets. The train can be propelled by a linear motor on the track or on the train, or both. Massive electrical induction coils are placed along the track in order to produce the magnetic field necessary to propel the train. Unmoving magnetic bearings using purely electromagnets or permanent magnets are unstable because of Earnshaw's theorem; on the other hand diamagnetic and superconducting magnets can support a maglev stably. Conventional maglev systems are stabilized with electromagnets that have electronic stabilization. The weight of the large electromagnet is a major design issue. A very strong magnetic field is required to levitate a massive train, so conventional maglev research is using superconductor research for an efficient electromagnet.

Inductrack

A newer, perhaps less-expensive, system is called "Inductrack". The technique has a load-carrying ability related to the speed of the vehicle, because it depends on currents induced in a passive electromagnetic array by permanent magnets. In the prototype, the permanent magnets are in a cart; horizontally to provide lift, and vertically to provide stability. The array of wire loops is in the track. The magnets and cart are unpowered, except by the speed of the cart. Inductrack was originally developed as a magnetic motor and bearing for a flywheel to store power. With only slight design changes, the bearings were unrolled into a linear track. Inductrack was developed by physicist Richard Post at Lawrence Livermore National Laboratory. Inductrack uses Halbach arrays for stabilization. Halbach arrays are arrangements of permanent magnets that stabilize moving loops of wire without electronic stabilization. Halbach arrays were originally developed for beam guidance of particle accelerators. They also have a magnetic field on the track side only, thus reducing any potential effects on the passengers.

Spacecraft research

Currently, some space agencies, such as NASA, are researching the use of maglev systems to launch spacecraft. In order to do so, the space agency would have to get a maglev-launched spacecraft up to escape velocity, a task that would otherwise require elaborate timing of magnetic pulses (see coilgun) or a very fast, very powerful electric current (see railgun). Maglev-launching could also be used to make conventional launches more efficient: accelerating a craft up to mach 1 before firing the main engines can save 30% of the weight of the launch vehicle (Heller, 1998).

Pros and Cons of different technologies

Each implementation of the magnetic levitation principle for train-type travel involves advantages and disadvantages. Time will tell as to which principle, and whose implementation, wins out commercially. It must be noted, that the Inductrack and the Superconducting EDS are only levitation technologies. In both cases, vehicles need some other technology for propulsion. A linear motor is used for propulsion in Japanese Superconducting EDS MLX01 maglev. Inductrack, should it ever be developed into a commercial transport technology, will have to solve the propulsion problem, as well as the need to deliver the propulsion energy onboard (due to itself being a completely passive technology). A Jet engine or a linear motor are being considered. The German Transrapid electromagnetic maglev uses a linear motor for both levitation and propulsion. Neither Inductrack nor the Superconducting EDS are able to levitate vehicles at a standstill, although Inductrack provides levitation down to a much lower speed. Wheels are required for both systems, whereas EMS systems are wheel-less. The German Transrapid, Japanese HSST (Linimo), and Korean Rotem maglevs levitate at a standstill, with electricity delivered from guideway power rails. If guideway power is lost on the move, the Transrapid is still able to generate levitation down to 10 km/h speed, using the power from onboard batteries. This is not the case with the HSST and Rotem systems.

Existing Maglev Systems

Jet engine]]

Birmingham 1984–1995

The world's first commercial automated system was a low-speed maglev shuttle that ran from the airport terminal of Birmingham International Airport (UK) to the nearby Birmingham International railway station from 1984 to 1995. The length of the track was 600 m, and trains "flew" at an altitude of 15 mm. It was in operation for nearly eleven years, but obsolescence problems with the electronic systems made it unreliable in its later years and it has now been replaced with a cable-drawn system.

Berlin 1989–1991

In Berlin, the M-Bahn was built in the 1980s: a driverless maglev system with a 1.6 km track connecting three U-Bahn (metro) stations. Testing in passenger traffic started in August 1989, and regular operation started in July 1991. Because of traffic changes after the fall of the Berlin Wall, deconstruction of the line began only two months later and was completed in February 1992. The line was replaced by a regular U-Bahn line.

Transrapid

Transrapid, a German maglev company with a test track in Emsland, constructed the first operational high-speed conventional maglev railway in the world, the Shanghai Maglev Train from downtown Shanghai, China to the new Shanghai airport at Pudong. It was inaugurated in 2002. The highest speed achieved on the Shanghai track has been 501 km/h (311 mph), over a track length of 30 km. Transrapid uses EMS technology.

JR-Maglev

Japan has a test track in Yamanashi prefecture where test trains JR-Maglev MLX01 have reached 581 km/h (363 mph), faster than wheeled trains. These trains use superconducting magnets which allow for a larger gap, and repulsive-type "Electro-Dynamic Suspension" (EDS). In comparison Transrapid uses conventional electromagnets and attractive-type "Electro-Magnetic Suspension" (EMS). These "Superconducting Maglev Shinkansen", developed by the Central Japan Railway Co. ("JR Central") and Kawasaki Heavy Industries, are currently the fastest trains in the world, achieving a record speed of 581 km/h on December 2, 2003. If a proposed Chuo Shinkansen is built, connecting Tokyo to Osaka by maglev, this test track would be part of the line.

Linimo, Nagoya East Hill Line

The world's first commercial automated "Urban Maglev" system commenced operation in March 2005 in Japan. This is the nine-station 8.9 km-long Tobu-kyuryo Line Linimo, otherwise known as the Nagoya East Hill Line. The line has a minimum operating radius of 75 m and a maximum gradient of 6%. The linear-motor magnetic-levitated train has a top speed of 100 km/h. The line serves the local community as well as the Expo 2005 fair site. The trains were designed by the Chubu HSST Development Corporation, which also operates a test track in Nagoya. Urban-type maglevs patterned after the HSST have been constructed and demonstrated in Korea, and a Korean commercial version Rotem is now under construction in Daejeon and projected to go into operation by April of 2007.

FTA's UMTD program

In the US, the Federal Transit Administration (FTA) Urban Maglev Technology Demonstration program has funded the design of several low-speed urban maglev demonstration projects. It has assessed HSST for the Maryland Department of Transportation and maglev technology for the Colorado Department of Transportation. The FTA has also funded work by General Atomics at California University of Pennsylvania to demonstrate new maglev designs, the MagneMotion M3 and of the Maglev2000 of Florida superconducting EDS system. Other US urban maglev demonstration projects of note are the LEVX in Washington State and the Massachusetts-based Magplane.

Southwest Jiaotong University, China

On December 31, 2000, the first crewed high-temperature superconducting maglev was tested successfully at Southwest Jiaotong University, Chengdu, China. This system is based on the principle that bulk high-temperature superconductors can be levitated or suspended stably above or below a permanent magnet. The load was over 530 kg and the levitation gap over 20 mm. The system uses liquid nitrogen, which is very cheap, to cool the superconductor.

US patent, 1969

The first patent for a magnetic levitation train propelled by linear motors was US patent 3,470,828, issued in October 1969 to James R. Powell and Gordon T. Danby. The technology underlying it was invented by Eric Laithwaite, and described by him in "Proceedings of the Institution of Electrical Engineers", vol. 112, 1965, pp. 2361-2375, under the title "Electromagnetic Levitation". Laithwaite patented the linear motor in 1948.

Economics

High-speed maglevs can be expensive to build, but are comparable to the capital costs of building a traditional high-speed rail system from scratch, a highway system or a system of airports. More importantly, maglevs are significantly less expensive to operate and maintain (O&M) than traditional high-speed trains, planes or intercity buses. The data coming out of the Shanghai maglev demonstration project indicates that O&M costs are quite low, and are indeed covered by the current relatively low volume of 7,000 passengers per day. Ridership on this Pudong International Airport line is expected to rise dramatically once the line is extended from Longyang Road metro station all the way to Shanghai's downtown train depot. The Shanghai maglev cost US$1.2B to build which means that at 20,000 passengers a day at US$6 per passenger it will take around 30 years to pay off just the capital costs, not accounting for track maintenance, salaries and electricity. This computes to US$60 million per mile. The proposed Chuo Shinkansen line is estimated to cost approximately US$82 billion to build. However, when one considers the cost of airport construction ($70 billion for a new airport) and 8-lane Interstate highway systems that cost around US$50 million per mile, it becomes immediately apparent that maglev's costs are competitive, especially considering that they can handle much higher volumes of passengers per hour than airports or 8-lane highways and do it without introducing any air pollution along their ROW's (right of way). Low-speed maglevs (100 km/h, or 60 mph), such as the Japanese HSST or Korean Rotem, are expected to cost somewhere around US$30 million per mile. Besides offering improved O&M costs over other transit systems, these low-speed maglevs provide ultra-high levels of operational reliability and introduce zero noise or air pollution into dense urban settings. As maglev systems are deployed around the world, experts fully expect construction costs to drop as new construction methods are perfected.

Proposals

Shanghai-Hangzhou

China is considering maglev as a possible technology option for building a planned high-speed rail network to connect major cities, although the cost may make this impractical. Talks with Germany on the possible construction of a second Transrapid maglev rail linking Shanghai to Hangzhou have started. The Shanghai-Hangzhou maglev line would become the first inter-city Maglev rail line in commercial service in the world. The line will be an extension of the only other Maglev line in commercial service, the Shanghai airport Maglev line. The new line would have to be in service no later than 2010.

London-Glasgow

A maglev line has recently been proposed in the United Kingdom from London to Glasgow with several route options through the Midlands and Northeast, and is reported to be under favourable consideration by the government. [http://www.expall.com/ultraspeed.html] [http://www.guardian.co.uk/transport/Story/0,2763,1545279,00.html]

Honolulu

The city of Honolulu, Hawaii is said to be planning a Linimo class urban Maglev for its main mass transit train.

Philadelphia

In Philadelphia a maglev project is being studied that would connect to the city's international airport and urban core, with additional links being added in the planning stages.

San Diego

San Diego is considering a high-speed maglev line to the Imperial County Airport.

Southern California, Las Vegas

High-speed maglev lines between major cities of southern California and Las Vegas are also being studied. This plan was originally supposed to be part of a I-5 or I-15 expansion plan, but the federal government has ruled it must be separated from interstate work projects.

Baltimore-Washington

A 64 km project linking Camden Yard in Baltimore and Baltimore-Washington International (BWI) Airport to Union Station in Washington, D.C.

Pittsburgh

A 75 km project linking Pittsburgh Airport to Pittsburgh and its eastern suburbs.

Vactrain

:see also Swissmetro More exotic proposals include maglev lines through vacuum-filled tunnels (see Vactrain), where the absence of air resistance would allow extremely high speeds, up to 6000-8000 km/h (4000-5000 mph) according to some sources. Theoretically, these tunnels could be built deep enough to pass under oceans or to use gravity to assist the trains' acceleration. This would likely be prohibitively costly without major advances in tunnelling technology. Alternatives such as elevated concrete tubes with partial vacuums have been proposed to reduce these costs. If the trains topped out at around 8000 km/h (5000 mph), the trip between London and New York would take a breathtakingly short 54 minutes, effectively supplanting aircraft as the world's fastest mode of public transportation.

UniModal

UniModal is a proposed personal rapid transit system using Inductrack suspension to achieve average commute speeds of 160 km/h (100 mph) in the city.

References

External links

Transrapid

- [http://www.maglevboard.net The International Maglev Board]
- [http://www.transrapid.de/ Transrapid]
- [http://www.transrapid.de/en/medien/praesentation/1.html Slideshow on the Transrapid]
- [http://home.wangjianshuo.com/archives/20030809_pudong_airport_maglev_in_depth.htm Shanghai Pudong Airport Maglev in depth]
- [http://www.expall.com/ultraspeed.html The UK Ultraspeed Project]
- [http://www.magneetzweefbaan.nl/ Consortium Transrapid Nederland]
- [http://www.bwmaglev.com/ Baltimore-Washington Maglev Project]
- [http://www.calmaglev.org/ California Maglev Project]
- [http://www.magnetbahn-bayern.de/ Magnetbahn-bayern]
- [http://www.bmg-bayern.de/index.php Bmg-bayern]
- [http://faculty.washington.edu/~jbs/itrans/maglevq.htm Maglev Quicklinks]
- [http://www.swissmetro.com/ Swissmetro]

Japanese Maglev

Linear Motor Car

- [http://www.rtri.or.jp/rd/maglev/html/english/mlx01_E.html RTRI MLX01]
- [http://www.rtri.or.jp/rd/maglev/html/english/maglev_introduction_E.html RTRI Maglev R&D]
- [http://www.rtri.or.jp/rd/maglev/html/english/maglev_technology_E.html RTRI Technologies of Maglev] ----
- [http://www.pref.yamanashi.jp/cgi-bin/linear/index.cgi Yamanashi Linear Express Fan Club (in Japanese)]
- [http://mlx01.fc2web.com/ A site with MLX01 video and photo (in Japanese)]
- [http://gvideo.eizou.pref.yamanashi.jp/real/event/Linear2003.ram MLX01 Video] ----
- [http://www.rtri.or.jp/index.html Railway Technical Research Institute (RTRI)]
- [http://www.rtri.or.jp/rd/maglev/html/english/maglev_frame_E.html RTRI Maglev Systems Development Department]
- [http://jr-central.co.jp/english.nsf/index Central Japan Railway Company]
- [http://jr-central.co.jp/eng.nsf/english/chuo_shinkansen Central Japan Railway Company - Chuo Shinkansen]
- [http://jr-central.co.jp/eng.nsf/english/maglev Central Japan Railway Company - Superconducting Maglev]
- [http://linear.jr-central.co.jp/ Central Japan Railway Company - Linear Express]
- [http://www.linear-chuo-exp-cpf.gr.jp/ Linear Chuo Express (in Japanese)]
- [http://www.linear-chuo-exp-cpf.gr.jp/kidsweb/index.html Linear Chuo Express for kids website (in Japanese)]
- [http://www.pref.aichi.jp/kotsu/rinia/index_e.html Linear Chuo Shinkansen Project] ----
- [http://www.pref.yamanashi.jp/cgi-bin/linear/link.cgi Other Japanese Maglev Links]

Linimo

- [http://www.linimo.jp/ Linimo]

Maglev train companies

These websites contain further information provided by companies building maglev trains (alphabetical order).
- [http://www.ga.com/atg/ems.php General Atomics] (USA)
- [http://hsst.jp/ HSST] (Japan)
- [http://www.maglev2000.com/ Maglev2000] (USA)
- [http://www.rotem.co.kr/ Rotem] (Korea)
- [http://www.transrapid.de/ Transrapid International] (Germany)
- [http://www.expall.com/ultraspeed.html Ultraspeed] (UK; uses Transrapid technology)
- [http://www.swissmetro.com/ Swissmetro] (Switzerland)
- [http://www.boeing.com/defense-space/space/maglev/index.html#1 Boeing]

General

- [http://www.fra.dot.gov/us/content/200 Federal Railroad Administration - MAGLEV]
- [http://www.fra.dot.gov/downloads/RRdev/maglev-sep05.pdf Report to Congess: Costs and Benefits of Magnetic Levitation]
- [http://urbanmaglev.org Urban Maglev Interest Group]
- [http://www.maglev.de Maglev in Asia (China, Shanghai), Japan (Yamanashi) and Germany (Munich; TVE)]
- [http://www.llnl.gov/str/Post.html Lawrence Livermore's InducTrack Site]
- UniModal personal rapid transit system
- [http://www.railserve.com/maglev.html Magnetic Levitation for Transportation] Category:Electric railways Category:Electric vehicles Category:Magnetic devices Category:Monorails ja:磁気浮上式鉄道

Multiple unit

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.

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. 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. 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. 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. 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. Some well known examples of multiple units are all of the Japanese Shinkansen and the last generation German ICE. Most trains in Netherlands and Japan are multiple units, which is suitable for railway in high population density area. Even MUs type freight train (Type M250) is produced in Japan in 2004.

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. EMUs are used on AMT's Montreal/Deux-Montagnes line.

External links

- [http://www.vintagecarriagestrust.org/surveystatus.htm Preserved Carriage Database] Category:Multiple units ja:動力分散方式

Diesel 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 energy (such as a spark plug), as is the case in the gasoline engine. This is known as the diesel cycle, after German engineer Rudolf Diesel, who invented it in 1892 and received the patent on February 23, 1893 (1893-02-23). Diesel intended the engine to use a variety of fuels including coal dust. He demonstrated it in the 1900 Exposition Universelle (World's Fair) using peanut oil (see biodiesel).

How diesel engines work

When a gas is compressed, its temperature rises (see the combined gas law); a diesel engine uses this property to ignite the fuel. Air is drawn into the cylinder of a diesel engine and compressed by the rising piston at a much higher compression ratio than for a spark-ignition engine, up to 25:1. The air temperature reaches 700–900 °C, or 1300–1650 °F. At the top of the piston stroke, diesel fuel is injected into the combustion chamber at high pressure, through an atomising nozzle, mixing with the hot, high-pressure air. The resulting mixture ignites and burns very rapidly. This contained explosion causes the gas in the chamber to heat up rapidly, which increases its pressure, which in turn forces the piston downwards. The connecting rod transmits this motion to the crankshaft, which is forced to turn, delivering rotary power at the output end of the crankshaft. Scavenging (pushing the exhausted gas-charge out of the cylinder, and drawing in a fresh draught of air) of the engine is done either by ports or valves. To fully realize the capabilities of a diesel engine, use of a turbocharger to compress the intake air is necessary; use of an aftercooler/intercooler to cool the intake air after compression by the turbocharger further increases efficiency. In very cold weather, diesel fuel thickens and increases in viscosity and forms wax crystals or a gel. This can make it difficult for the fuel injector to get fuel into the cylinder in an effective manner, making cold weather starts difficult at times, though recent advances in diesel fuel technology have made these difficulties rare. A commonly applied advance is to electrically heat the fuel filter and fuel lines. Other engines utilize small electric heaters called glow plugs inside the cylinder to warm the cylinders prior to starting. A small number use resistive grid heaters in the intake manifold to warm the inlet air until the engine reaches operating temperature. Engine block heaters (electric resistive heaters in the engine block) plugged into the utility grid are often used when an engine is shut down for extended periods (more than an hour) in cold weather to reduce startup time and engine wear. A vital component of any diesel engine system is the governor, which limits the speed of the engine by controlling the rate of fuel delivery. Older governors were driven by a gear system from the engine (and thus supplied fuel only linearly with engine speed). Modern electronically-controlled engines achieve this through the electronic control module (ECM) or electronic control unit (ECU) - the engine-mounted "computer". The ECM/ECU receives an engine speed signal from a sensor and then using its algorithms and look-up calibration tables stored in the ECM/ECU, it controls the amount of fuel and its timing (the "start of injection") through electric or hydraulic actuators to maintain engine speed. Controlling the timing of the start of injection of fuel into the pistons is key to minimising their emissions and maximising the fuel economy (efficiency) or the engine. The exact timing of starting this fuel injection into the cylinder is controlled electronically in most of today's modern engines. The timing is usually measured in units of crank angles before Top Dead Center (TDC) that the piston is at. For example, if the ECM/ECU initiates fuel injection when the piston is 10 degrees before TDC, the start of injection or "timing" is said to be 10 deg BTDC. The optimal timing will depend on both the engine design as well as its speed and load. Advancing (injecting when the piston is further away from TDC) the start of injection results in higher in-cylinder pressure and higher efficiency but also results in higher Nitrous Oxide (NOx) emissions. At the other extreme, very retarded start of injection or timing causes incomplete combustion. This results in higher Particulate Matter (PM) emissions and higher smoke.

Fuel injection in diesel engines

Early diesels often employed indirect injection in order to use simple, flat-top pistons, and made the positioning of the early, bulky diesel injectors easier, but all modern diesel engines employ some form of direct injection, coupled with more complicated bowl-in-piston designs. Modern engines also use a very highly pressurised fuel supply line, which replaces the older, noisier, and mechanically more complicated combined pump and selector valve assembly (see below).

Indirect Injection

An indirect injection diesel engine delivers fuel into a chamber off the combustion chamber, called a prechamber, where combustion begins and then spreads into the main combustion chamber. The prechamber is carefully designed to ensure adequate mixing of the atomized fuel with the compression-heated air. This has the effect of slowing the rate of combustion, which tends to reduce audible noise. It also softens the shock of combustion and produces lower stresses on the engine components. The addition of a prechamber, however, increases heat loss to the cooling system and thereby lowers engine efficiency.

Direct injection

Modern diesel engines make use of one of the following direct injection methods:

Common rail direct injection

The common rail system on its prototype was already developed in late sixties with Mr. Hiber in Switzerland. After that, Ganser of the Swiss Federal Institute of Technology focusing on his research the common rail technology was advanced. In mid nineties, Dr. Shohei Itoh and Masahiko Miyaki, Japanese automotive parts manufacturer Denso Corporation, developed the Common Rail Fuel System for Heavy Duty Vehicles and finally turned into its first practical use on their ECD-U2 common Rail system, which was mounted on the HINO RAISING RANGER truck and sold for general use in 1995. Later in 1997 the German automotive parts manufacturer Robert Bosch GmbH extended its use for passenger car. Today the common rail system is responsible for a revolution in diesel engine technology. Delphi Automotive Systems of the US also make common-rail systems. Different car makers refer to their common rail engines by different names, e.g. DaimlerChrysler's CDI, Ford Motor Company's TDCi (most of these engines are manufactured by PSA), Fiat Group's (Fiat, Alfa Romeo and Lancia) JTD, Renault's DCi, GM/Opel's CDTi (most of these engines are manufactured by Fiat, other by Isuzu), PSA Peugeot Citroen's HDI, Toyota's D-4D, and so on. In older diesel engines, a distributor-type injection pump, regulated by the engine, supplies bursts of fuel to injectors which are simply nozzles through which the diesel is sprayed into the engine's combustion chamber. As the fuel is at low pressure and there cannot be precise control of fuel delivery, the spray is relatively coarse and the combustion process is relatively crude and inefficient. In common rail systems, the distributor injection pump is eliminated. Instead an extremely high pressure pump stores a reservoir of fuel at high pressure - up to 1,800 bar (180 MPa) - in a "common rail", basically a tube which in turn branches off to computer-controlled injector valves, each of which contains a precision-machined nozzle and a plunger driven by a solenoid. Driven by a computer (which also controls the amount of fuel to the pump), the valves, rather than pump timing, control the precise moment when the fuel injection into the cylinder occurs and also allow the pressure at which the fuel is injected into the cylinders to be increased. As a result, the fuel that is injected atomises easily and burns cleanly, reducing exhaust emissions and increasing efficiency. In addition, the engine's Electronic Control Unit (ECU) can inject a small amount of diesel just before the main injection event ("pilot" injection) that reduces noise and vibration, as well as optimises injection timing and quantity for variations in fuel quality, cold starting, and so on. Most European automakers have common rail diesels in their model lineups, even for commercial vehicles. Some Japanese manufacturers, such as Toyota, Nissan and recently Honda, have also developed common rail diesel engines.

Unit direct injection

This also injects fuel directly into the cylinder of the engine. However, in this system the injector and the pump are combined into one unit positioned over each cylinder. Each cylinder thus has its own pump, feeding its own injector, which prevents pressure fluctuations and allows more consistent injection to be achieved. This type of injection system, also developed by Bosch, is used by Volkswagen AG in cars, and most major diesel engine manufactures, in large commercial engines (Cat, Cummins, Detroit Diesel). With recent advancements, the pump pressure has been raised to 2,050 bar (205 MPa), allowing injection parameters similar to common rail systems.

Types of diesel engines

There are two classes of diesel engines: two-stroke and four-stroke. Most diesels generally use the four-stroke cycle, with some larger diesels operating on the two-stroke cycle. Normally, banks of cylinders are used in multiples of two, although any number of cylinders can be used as long as the load on the crankshaft is counterbalanced to prevent excessive vibration. The inline-6 is the most prolific in medium- to heavy-duty engines, though the V8 and straight-4 are also common.

Advantages and disadvantages versus spark-ignition engines

Diesel engines are more efficient than gasoline/petrol engines of the same power (by approx. 15%), resulting in lower fuel consumption. Naturally aspirated diesel engines are more massive than gasoline/petrol engines of the same power for two reasons; the first is that it takes a larger capacity diesel engine than a gasoline engine to produce the same power. This is essentially because the diesel cannot operate as quickly - the "rev limit" is lower - because getting the fuel-air mixture into a diesel engine is more difficult than a gasoline engine [http://www.perkins.com/perkins/cda/articleDisplay/1,4094,7___32_____7_10020408,00.html]. The second reason is that a diesel engine must be stronger to withstand the higher combustion pressures needed for ignition. Yet it is this same build quality that has allowed some enthusiasts to acquire significant power increases with turbocharged engines through fairly simple and inexpensive modifications. A gasoline engine of similar size cannot put out a comparable power increase without extensive alterations because the stock components would not be able to withstand the higher stresses placed upon them. Since a diesel engine is already built to withstand higher levels of stress, it makes an ideal candidate for performance tuning with little expense. However it should be said that any modification that raises the amount of fuel and air put through a diesel engine will increase its operating temperature which will reduce its life and service interval requirements. In addition, sending additional fuel to the cylinders will wash away lubricating oil faster. These things are issues with newer, lighter, "high performance" diesel engines which aren't "overbuilt" to the degree of older engines and are being pushed to provide greater power in smaller engines. The addition of a turbocharger or supercharger to the engine (see turbodiesel) greatly assists in increasing fuel economy and power output. Boost pressures can be higher on diesels than gasoline engines, and the higher compression ratio allows a diesel engine to be more efficient than a comparable spark ignition engine, although the calorific value of the fuel is slightly lower at 45.3 megajoules per kilogram to gasoline at 45.8 MJ/kg. The increased fuel economy of the diesel over the petrol engine means that the diesel produces less carbon dioxide (CO₂) per unit distance. The recent development of biofuel alternatives to fossil fuels has unleashed the ability to produce a net-sum of zero emissions of CO₂, as it is re-absorbed into plants and then comes full circle, being used to produce the fuel. Diesel engines can produce black soot from their exhaust. This consists of unburned carbon compounds. Modern diesel engines catch the soot in a particle filter, which when saturated is automatically regenerated by burning the particles. Other problems associated with the exhaust gases (nitrogen oxide, sulfurous fumes) can be mitigated with further investment and equipment. The lack of an electrical ignition system greatly improves the reliability. The high durability of a diesel engine is also due to its overbuilt nature (see above) as well as the diesel's combustion cycle, which creates less-violent changes in pressure when compared to a spark-ignition engine, a benefit that is magnified by the lower rotating speeds in diesels. Unfortunately, due to the greater compression force required and the increased weight of the stronger components, starting a diesel engine is a harder task. More torque is required to push the engine through compression. Either an electrical starter or an air start system is used to start the engine turning. On large engines, pre-lubrication and slow turning of an engine, as well as heating, are required to minimize the possibility of damaging the engine during initial start-up and running. Some smaller military diesels can be started with an explosive cartridge that provides the extra power required to get the machine turning. In the past, Caterpillar and John Deere used a small gasoline "pony" motor in their tractors to start the primary diesel motor. The pony motor heated the diesel to aid in ignition and utilized a small clutch and transmission to actually spin up the diesel engine. Even more unusual was an International Harvester design in which the diesel motor had its own carburetor and ignition system, and started on gasoline. Once warmed up, the operator moved two levers to switch the motor to diesel operation, and work could begin. These engines had very complex cylinder heads (with their own gasoline combustion chambers) and in general were vulnerable to expensive damage if special care was not taken (especially in letting the engine cool before turning it off).

Automobile racing

Although the weight and lower output of a diesel engine tend to keep them away from automotive racing applications, there are many diesels being raced in classes that call for them, mainly in truck racing, as well in types of racing where these drawbacks are less severe, such as land speed record racing. [http://www.cumminsracing.com/ Diesel engined dragsters] even exist, despite the diesel's drawbacks being central to performance in this sport. In 1952, [http://www.cummins.com/eu/pages/en/whoweare/cumminshistory.cfm Cummins Diesel] won the pole at the Indianapolis 500 race with a supercharged 3 liter diesel car, relying on torque and fuel efficiency to overcome weight and low peak power, and led most of the race until the badly situated air intake of the car swallowed enough debris from the track to disable the car.

Dieseling in spark-ignition engines

A gasoline (spark ignition) engine can sometimes act as a compression ignition engine under abnormal circumstances, a phenomenon typically described as "pinging" or "pinking" (during normal running) or "dieseling" (when the engine continues to run after the electrical ignition system is shut off). This is usually caused by hot carbon deposits within the combustion chamber that act as would a "glow plug" within a diesel or model aircraft engine. Excessive heat can also be caused by improper ignition timing and/or fuel/air ratio which in turn overheats the exposed portions of the spark plug within the combustion chamber.

Fuel and fluid characteristics

Diesel engines can operate on a variety of different fuels, depending on configuration, though the eponymous diesel fuel derived from crude oil is most common. Good-quality diesel fuel can be synthesised from vegetable oil and alcohol. Biodiesel is growing in popularity since it can frequently be used in unmodified engines, though production remains limited. Petroleum-derived diesel is often called "petrodiesel" if there is need to distinguish the source of the fuel. The engines can work with thicker, heavier oil, or oil with higher viscosity, as long as it is heated to ease pumping and injection. These fuels are cheaper than clean, refined diesel oil, although they are dirtier. The biofuels straight vegetable oil (SVO) and waste vegetable oil (WVO) can fall into this category. Moving beyond that, use of low-grade fuels can lead to serious maintenance problems. Most diesel engines that power ships like supertankers are built so that the engine can safely use low grade fuels. Ethanol is also used in some cases, since it has a high octane rating which means it can be highly compressed before spontaneously igniting. One way this is used is in E95 fuel which actually contains 5% gasoline along with 95% ethanol. Normal diesel fuel is more difficult to ignite than gasoline because of its higher flash point, but once burning, a diesel fire can be extremely fierce.

Diesel applications

The vast majority of modern heavy road vehicles (trucks), ships, large-scale portable power generators, most farm and mining vehicles, and many long-distance locomotives have diesel engines. However, in the U.S. they are not as popular in passenger vehicles as they are in Europe as they are perceived as being heavier, noisier, of having performance characteristics which makes them slower to accelerate, and of being more expensive than petrol vehicles. In addition, before the mandatory reduction of sulphur in on-road diesel fuel to 15 parts per million, which will start at 15 Oct 2006 (2006-10-15) in the U.S. (1 June 2006 (2006-06-01) in Canada), diesel fuel used in North America has higher sulphur content than the fuel used in Europe, effectively limiting diesel use to industrial vehicles. 2006-06-01 In Europe, where tax rates in many countries make diesel fuel much cheaper than petrol, diesel vehicles are very popular and newer designs have significantly narrowed differences between petrol and diesel vehicles in the areas mentioned. One anecdote tells of Formula One driver Jenson Button, who was arrested while driving a diesel-powered BMW coupe at 230 km/h (about 140 mph) in France, where he was too young to have a petrol-engined car hired to him. Button dryly observed in subsequent interviews that he had actually done BMW a public relations service, as nobody had believed a diesel could be driven that fast. The BMW diesel lab in Steyr, Austria is led by Ferenc Anisits and is considered to be a leader in development of automotive diesel engines. Similarly, Mercedes Benz had a successful run of diesel-powered passenger cars in the late 1970s and 1980s. After a hiatus in the 1990s with relatively few diesel cars in its lineup, Mercedes Benz has revived diesel cars in its newer ranges with an emphasis on high performance versus the older models' lack thereof. ;High-Speed :High-speed (approximately 1200 rpm and greater) engines are used to power lorries (trucks), buses, tractors, cars, yachts, compressors, pumps and small generators. ;Medium-Speed :Large electrical generators are driven by medium speed engines, (approximately 300 to 1200 rpm) optimised to run at a set speed and provide a rapid response to load changes. ;Low-Speed : The largest diesel engines are used to power ships. These monstrous engines have power outputs over 80,000 kW, turn at about 60 to 100 rpm, and are up to 15 m tall. They often run on cheap low-grade fuel, which require extra heat treatment in the ship for tanking and before injection due to their low volatility. Companies such as Burmeister & Wain and Wärtsilä (e.g., Sulzer Diesels) design such large low speed engines. They are unusually narrow and tall due to the addition of a crosshead bearing. Today (2005), the Wärtsilä-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world, with cylinder bores of 960 mm (37.8 in) and stroke of 2500 mm (98.4 in), producing up to 80,080 kW (107,389 hp) in the 14-cylinder configuration. The zeppelins Graf Zeppelin II and Hindenburg were propelled by reversible diesel engines. The direction of operation was changed by shifting gears on the camshaft. From full power forward, the engines could be brought to a stop, changed over, and brought to full power in reverse in less than 60 seconds. This was done before reversible pitch propellers for aircraft had been perfected. A few airplanes have been built that use diesel engines, such as the Junkers-powered Blohm & Voss Ha 139 of the late 1930s. This is quite rare because of the high importance of power-weight ratios in aeronautical applications, and the development of kerosene-powered jet engines and the closely-related turboprop engines. However, this may change in the near future. The newer automotive diesels have power-weight ratios comparable to the ancient spark-ignition designs common in general aviation aircraft, and have better fuel efficiency. Their use of electronic ignition, fuel injection, and sophisticated engine management systems also makes them far easier to operate than mass-produced spark-ignition aircraft engines, most of which still use carburetors. Combined with Europe's very favourable tax treatment of diesel fuel compared to petrol, these factors have led to considerable interest in diesel-powered small general aviation planes, and several manufacturers have recently begun selling diesel engines for this purpose. The Diamond Twin Star is currently one of the very few general aviation aircraft manufactured with diesel engines. It can be twice as efficient as a comparable twin aircraft due to the diesel engines made by Thielert. Another major advantage for aviation users is that diesel engines can be fuelled with jet fuel, which is produced in a much greater quantity than avgas. See aircraft engine. Also, some motorcycles have been built using diesel engines.

Current and future developments

Already, many common rail and unit injection systems employ new injectors using stacked piezoelectric crystals in lieu of a solenoid, which gives finer control of the injection event. Variable geometry turbochargers have flexible vanes, which move and let more fuel into the engine depending on load. This technology increases both performance and fuel economy A technique called accelerometer pilot control (APC) uses a sensor called an accelerometer to provide feedback on the engine's level of noise and vibration and thus instruct the ECU to inject the minimum amount of fuel that will produce quiet combustion and still provide the required power (especially while idling.) The next generation of common rail diesels are expected to use variable injection geometry, which allows the amount of fuel injected to be varied over a wider range, and variable valve timing similar to that on gasoline engines. At least in the US, diesels will slowly face displacement by tougher emissions regulations. Other methods to achieve even more efficient combustion, such as HCCI (homogeneous charge compression ignition), are being studied.

Modern diesel facts

(Source: Robert Bosch GmbH) Fuel passes through the injector jets at speeds of nearly 1500 miles per hour (2400 km/h) – as fast as the top speed of a jet plane. Fuel is injected into the combustion chamber in less than 1.5 milliseconds (one and a half thousandths of a second) – about as long as a camera flash. The smallest quantity of fuel injected is one cubic millimetre – about the same volume as the head of a pin. The largest injection quantity at the moment for automobile diesel engines is around 70 cubic millimetres. If the camshaft of a six-cylinder engine is turning at 4500 rpm, the injection system has to control and deliver 225 injection cycles per second. On a demonstration drive, a Volkswagen 1-liter diesel-powered car used only 0.89 liters of fuel in covering 100 kilometers – making it probably the most fuel-efficient car in the world. Bosch’s high-pressure fuel injection system was one of the main factors behind the prototype’s extremely low fuel consumption. Production record-breakers in fuel economy include the Volkswagen Lupo 3L TDI and the Audi A2 3L 1.2 TDI with standard consumption figures of 3 liters of fuel per 100 kilometers. Their high-pressure diesel injection systems are also supplied by Bosch. In 2001, nearly 36% of newly registered cars in Western Europe had diesel engines. Austria leads the league table of registrations of diesel-powered cars with 66%, followed by Belgium with 63% and Luxembourg with 58%. Germany, with 34.6% in 2001, was in the middle of the league table. By way of comparison: in 1996, diesel-powered cars made up only 15% of the new car registrations in Germany. In 1998, for the very first time in the history of the legendary 24-hour race at the Nürburgring, a diesel-powered car was the overall winner – the BMW works team 320d, fitted with modern high-pressure diesel injection technology from Bosch.

External links

-
- [http://auto.howstuffworks.com/diesel.htm/ HowStuffWorks Article]
- [http://www.bath.ac.uk/~ccsshb/12cyl/ The Most Powerful Diesel Engine in the World]
- [http://www.cumminsracing.com Cummins Racing, home of the world's fastest diesel dragster...]
- [http://www.thedieselstop.com The Diesel Stop - Information on the Power Stroke Diesel]
- [http://www.northtexaspowerstrokes.com North Texas Power Stroke Association - Ford/International Power Stroke Diesel Enthusiasts]
- [http://www.rolls-royce.com/marine/product/diesel/default.jsp Rolls-Royce corporate website - diesel engines]
- [http://www.tdiclub.com TDIClub.com - TDI Enthusiasts]
- [http://www.turbodieselregister.com Turbodiesel Register - Dodge/Cummins Turbodiesel Enthusiasts]
- [http://www.volvo.com/volvopenta/global/en-gb Volvo Penta - manufacturer of marine and industrial diesel engines]
- [http://www.best-generator.com/ Best Engine - Manufacturer of Diesel Engine]
- [http://www.centurion-engines.com Centurion Engines - aeronautical applications]
- [http://www.wartsila.com/ Wärtsilä - manufacturer of diesel power plants]
- [http://www.cat.com/cda/layout?m=37532&x=7 Caterpillar - manufacturer of Caterpiller (Cat) diesel engines as well as construction equipment]
- [http://www.cummins.com Cummins - manufacturer of Cummins diesel engines]
- [http://www.detroitdiesel.com Detroit Diesel - manufacturer of diesel engines]
- [http://www.internationaldelivers.com/ -International/Navistar- manufacturer of International and Ford PowerStroke diesel engines, as well as heavy duty trucks]
- [http://www.perkins.com Perkins - manufacturer of diesel engines]
- [http://www.deutz.de Deutz - manufacturer of esoteric diesel engines]
- [http://www.deere.com John Deere - manufacturer of diesel engines and farm and construction equipment]
- [http://www.yanmar.com Yanmar - manufacturer of diesel engines, specilzing in those for marine use]
- [http://www.komatsu.com/kdl Komatsu Diesel - manufacturer of diesel engines]
- http://www.sisudiesel.com/ - Sisu Diesel
- [http://wagoneers.com/ wagoneers.com - see Mercedes Diesels and DIESELS] Category:Piston engines ko:디젤 엔진 ja:ディーゼルエンジン

Steam engine

A steam engine is a heat engine that makes use of the thermal energy that exists in steam, converting it to mechanical work. Steam engines were used in pumps, locomotives, steam ships and steam tractors, and were essential to the Industrial Revolution. They are still used for electrical power generation using steam turbines. A steam engine needs a boiler to boil water to produce steam under pressure. Any heat source can be used, but the most common is a fire fueled by wood, coal, or oil. (However, anything that can be burned can be used as fuel for the fire: paper, trash, used crankcase oil, ground-up corncobs, manure, natural gas, gasoline, high proof alcohol, dry grass, hay, dry weeds, etc). The steam expands and pushes against a piston or turbine, whose motion does the work of turning wheels or driving other machinery. In British English, the term steam engine my also refer to an entire steam locomotive.

Types of steam engine

Steam engines can be classified in two main ways:
- By the technology used. Most steam engines use either piston engines or turbines.
- By the application. Steam engines are used as:
- Stationary engines. Stationary steam engines again divide into two main classes:
- Winding engines, rolling mill engines, and similar applications which need to frequently stop and reverse.
- Engines providing power, which stop rarely and do not need to reverse. These include nearly all thermal power stations, and were also used in mills, factories and to power cable railways and cable tramways before the widespread use of electric power.
- Vehicle engines:
- Steamboats and steamships.
- Land vehicles:
- Steam locomotives.
- Steam cars.
- Steam rollers.
- Steam shovels.
- Traction engines.

Invention

Traction engine Traction engine.]] The first steam device, the aeolipile, was invented by Heron of Alexandria, a Greek, in the 1st century AD, but used only as a toy. Incidently 700 years earlier in Corinth, Greece, rail tracks were invented; however the Greeks never thought of putting the two together. In 1665 Edward Somerset, Marquis of Worcester, installed a steam-powered engine for pumping water in Raglan Castle. Denis Papin, a French physicist, built a working model of a steam engine in about 1687, and he is credited with a number of significant gadgets such as the safety valve. Sir Samuel Morland also developed ideas for a steam engine during the same period, he built a number of steam-engine pumps for Louis XIV in the 1680s. Early industrial steam engines were designed by Thomas Savery (The "fire-engine", 1698) and Thomas Newcomen (1712), and in 1769 James Watt patented what is essentially the modern steam engine - all later developments are refinements of Watt's principle changes rather than new features. Humphrey Gainsborough produced a model condensing steam engine in the 1760s. In 1802 William Symington built the "first practical steamboat", and in 1807 Robert Fulton used the Watt steam engine to power the first commercially successful steamboat. Early engines worked by the vacuum of condensing steam, whereas later types (such as steam locomotives) used the power of expanding steam.

Use and development

steam locomotive The first industrial applications of the vacuum engines were in the pumping of water from deep mineshafts. The Newcomen engine operated by admitting steam to the operating chamber, closing the valve, and then admitting a spray of cold water. The water vapor condenses to a much smaller volume of water, creating a vacuum in the chamber. Atmospheric pressure, operating on the opposite side of a piston, pushes the piston to the bottom of the chamber. In mineshaft pumps, the piston was connected to an operating rod that descended the shaft to a pump chamber. The oscillations of the operating rod are transferred to a pump piston that moves the water, through check valves, to the top of the shaft. The first significant improvement, 60 years later, was creation of a separate condensing chamber with a valve between the operating chamber and the condensing chamber. This improvement was invented on Glasgow Green, Scotland by James Watt and subsequently developed by him in Birmingham, England, to produce the Watt steam engine with greatly increased efficiency. The next improvement was the replacement of manually operated valves with valves operated by the engine itself. Such early vacuum, or condensing, engines are severely limited in their efficiency but are relatively safe since the steam is at very low pressure and structural failure of the engine will be by inward collapse rather than an outward explosion. Their power is limited by the ambient air pressure, the displacement of the working chamber, the combustion and evaporation rates, and the condenser capacity. The maximum theoretical efficiency is limited by the relatively low boiling point of water at near atmospheric pressure (100 °C, 212 °F). The next big improvement in efficiency came with Richard Trevithick's use of pressurized steam, which used a far greater pressure, but more importantly (from a thermodynamic standpoint) operates at a higher temperature differential. But with this added pressure came much danger and many disasters due to exploding boilers and machinery. The most important refinement at this point was the safety valve, which releases excess pressure. Reliable and safe operation came only with a great deal of experience and codification of construction, operating, and maintenance procedures.

Boilers

safety valve Supplement, Vol. XIX, No. 470, Jan. 3, 1885. Now on display in the National Museum of Science and Industry (The Science Museum), London.]] Boilers are of two main types:
- Fire tube construction is typical of early maritime installations for boats and ships and the boilers of steam locomotives. In a fire tube boiler, the hot gases from the firebox (a combustion chamber) are passed through tubes connecting perforated end plates. The gases then enter a smokebox or smoke chest and pass on to a smokestack. The boiler may be vertical or horizontal. For an example of a vertical boiler of this type observe the boiler in the small riverboat used in the movie The African Queen. This type is also used in some boilers that provide steam for steam heating of a building and was also used in the steam shovel. Locomotives and early ships used a horizontal orientation and early ships would usually require a tall smokestack to provide draft, not having a fan to provide a forced draft. In a steam locomotive the draft is generally augmented at startup by directing the steam exhaust through the smokestack, which provides a partial va

Train

Types of trains

Motive power

Passenger trains

See also

Freight trains

Famous train routes

Fictional trains

See also

Further reading

External links

Train (disambiguation)

See also

Permanent Way

Rail tracks

Railway rail

Axle load

Jointed track

Continuous welded rail

Methods of fixing rail to sleepers/ties

Track maintenance

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History

See also

Magnetic levitation train

Technology

Three types of technology

Inductrack

Spacecraft research

Pros and Cons of different technologies

Existing Maglev Systems

Birmingham 1984–1995

Berlin 1989–1991

Transrapid

JR-Maglev

Linimo, Nagoya East Hill Line

FTA's UMTD program

Southwest Jiaotong University, China

US patent, 1969

Economics

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Shanghai-Hangzhou

London-Glasgow

Honolulu

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References

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External links

Transrapid

Japanese Maglev

Linear Motor Car

Linimo

Maglev train companies

General

Multiple unit

History and description

Advantages of multiple units

North America

See also

External links

Diesel engine

How diesel engines work

Fuel injection in diesel engines

Indirect Injection

Direct injection

Common rail direct injection

Unit direct injection

Types of diesel engines

Advantages and disadvantages versus spark-ignition engines

Automobile racing

Dieseling in spark-ignition engines

Fuel and fluid characteristics

Diesel applications

Current and future developments