Maglev train facts for kids

Transrapid 09 at the Emsland test facility in Lower Saxony, Germany

Example of low-speed urban maglev system, Linimo

Maglev (derived from magnetic levitation) is a system of train transportation that uses two sets of electromagnets: one set to repel and push the train up off the track, and another set to move the elevated train ahead, taking advantage of the lack of friction. Such trains rise approximately 10 centimetres (4 in) off the track. There are both high-speed, intercity maglev systems (over 400 kilometres per hour or 250 miles per hour), and low-speed, urban maglev systems (80–200 kilometres per hour or 50–124 miles per hour) under development and being built. The Shanghai maglev train is the only maglev train in commercial operation that can be considered as high speed.

Development

In the late 1940s, the British electrical engineer Eric Laithwaite, a professor at Imperial College London, developed the first full-size working model of the linear induction motor. He became professor of heavy electrical engineering at Imperial College in 1964, where he continued his successful development of the linear motor.

The linear motor was naturally suited to use with maglev systems as well. In the early 1970s, Laithwaite discovered a new arrangement of magnets, the magnetic river, that allowed a single linear motor to produce both lift and forward thrust, allowing a maglev system to be built with a single set of magnets.

The first commercial maglev people mover was simply called "MAGLEV" and officially opened in 1984 near Birmingham, England. It operated on an elevated 600 metres (2,000 ft) section of monorail track between Birmingham Airport and Birmingham International railway station, running at speeds up to 42 kilometres per hour (26 mph). The system was closed in 1995 due to reliability problems.

Technology

The two main types of maglev technology are:

• Electromagnetic suspension (EMS), electronically controlled electromagnets in the train attract it to a magnetically conductive (usually steel) track.
• Electrodynamic suspension (EDS) uses superconducting electromagnets or strong permanent magnets that create a magnetic field, which induces currents in nearby metallic conductors when there is relative movement, which pushes and pulls the train towards the designed levitation position on the guide way.

High-speed maglev comparison with conventional high-speed trains

Maglev transport is non-contact and electric powered. It relies less or not at all on the wheels, bearings and axles common to wheeled rail systems.

• Speed: Maglev allows higher top speeds than conventional rail. While experimental wheel-based high-speed trains have demonstrated similar speeds, conventional trains will suffer from friction between wheels and track and thus elevating the maintenance cost if operating at such speed, unlike levitated maglev trains.
• Maintenance: Maglev trains currently in operation have demonstrated the need for minimal guideway maintenance. Vehicle maintenance is also minimal (based on hours of operation, rather than on speed or distance traveled). Traditional rail is subject to mechanical wear and tear that increases rapidly with speed, also increasing maintenance. For example: the wearing down of brakes and overhead wire wear have caused problems for the Fastech 360 rail Shinkansen. Maglev would eliminate these issues.
• Weather: In theory, maglev trains should be unaffected by snow, ice, severe cold, rain or high winds. However, as of yet no maglev system has been installed in a location with such a harsh climate.
• Acceleration: Maglev vehicles accelerate and decelerate faster than mechanical systems regardless of the slickness of the guideway or the slope of the grade, because they are non-contact systems.
• Track: Maglev trains are not compatible with conventional track, and therefore require custom infrastructure for their entire route. By contrast conventional high-speed trains such as the TGV are able to run, albeit at reduced speeds, on existing rail infrastructure, thus reducing expenditure where new infrastructure would be particularly expensive (such as the final approaches to city terminals), or on extensions where traffic does not justify new infrastructure. John Harding, former chief maglev scientist at the Federal Railroad Administration, claimed that separate maglev infrastructure more than pays for itself with higher levels of all-weather operational availability and nominal maintenance costs. These claims have yet to be proven in an intense operational setting and they do not consider the increased maglev construction costs. However, in countries like China, there are discussion of building some key conventional high-speed rail tunnels/bridges to a standard that would allow them upgrading to maglev.
• Efficiency: Conventional rail is probably more efficient at lower speeds. But due to the lack of physical contact between the track and the vehicle, maglev trains experience no rolling resistance, leaving only air resistance and electromagnetic drag, potentially improving power efficiency. Some systems, however, such as the Central Japan Railway Company SCMaglev use rubber tires at low speeds, reducing efficiency gains.
• Weight: The electromagnets in many EMS and EDS designs require between 1 and 2 kilowatts per ton. The use of superconductor magnets can reduce the electromagnets' energy consumption. A 50-ton Transrapid maglev vehicle can lift an additional 20 tons, for a total of 70 tons, which consumes 70–140 kilowatts (94–188 hp). Most energy use for the TRI is for propulsion and overcoming air resistance at speeds over 100 miles per hour (160 km/h).
• Weight loading: High-speed rail requires more support and construction for its concentrated wheel loading. Maglev cars are lighter and distribute weight more evenly.
• Noise: Because the major source of noise of a maglev train comes from displaced air rather than from wheels touching rails, maglev trains produce less noise than a conventional train at equivalent speeds. However, the psychoacoustic profile of the maglev may reduce this benefit: a study concluded that maglev noise should be rated like road traffic, while conventional trains experience a 5–10 dB "bonus", as they are found less annoying at the same loudness level.
• Magnet reliability: Superconducting magnets are generally used to generate the powerful magnetic fields to levitate and propel the trains. These magnets must be kept below their critical temperatures (this ranges from 4.2 K to 77 K, depending on the material). New alloys and manufacturing techniques in superconductors and cooling systems have helped address this issue.
• Control systems: No signalling systems are needed for high-speed maglev, because such systems are computer controlled. Human operators cannot react fast enough to manage high-speed trains. High-speed systems require dedicated rights of way and are usually elevated. Two maglev system microwave towers are in constant contact with trains. There is no need for train whistles or horns, either.
• Terrain: Maglevs are able to ascend higher grades, offering more routing flexibility and reduced tunneling.

High-speed maglev comparison with aircraft

Differences between airplane and maglev travel:

• Efficiency: For maglev systems the lift-to-drag ratio can exceed that of aircraft (for example Inductrack can approach 200:1 at high speed, far higher than any aircraft). This can make maglevs more efficient per kilometer. However, at high cruising speeds, aerodynamic drag is much larger than lift-induced drag. Jet-powered aircraft take advantage of low air density at high altitudes to significantly reduce air drag. Hence despite their lift-to-drag ratio disadvantage, they can travel more efficiently at high speeds than maglev trains that operate at sea level.
• Routing: Maglevs offer competitive journey times for distances of 800 kilometres (500 mi) or less. Additionally, maglevs can easily serve intermediate destinations.
• Availability: Maglevs are little affected by weather.
• Travel time: Maglevs do not face the extended security protocols faced by air travelers nor is time consumed for taxiing, or for queuing for take-off and landing.

With maglev technology, the train travels along a guideway of electromagnets which control the train's stability and speed. While the propulsion and levitation require no moving parts, the bogies can move in relation to the main body of the vehicle and some technologies require support by retractable wheels at low speeds under 150 kilometres per hour (93 mph). This compares with electric multiple units that may have several dozen parts per bogie. Maglev trains can therefore in some cases be quieter and smoother than conventional trains and have the potential for much higher speeds.

Economics

Despite over a century of research and development, there are only six operational maglev trains today — three in China, two in South Korea, and one in Japan. Maglev can be hard to economically justify for certain locations, however it has notable benefits over conventional railway systems, which includes lower operating and maintenance costs (with zero rolling friction its parts do not wear out quickly and hence less need to replace parts often), significantly lower odds of derailment (due to its design), an extremely quiet and smooth ride for passengers, little to no air pollution, and the railcars can be built wider and make it more comfortable and spacious for passengers. And also because it can travel up higher ascending grades (up to 10 percent), compared to conventional trains (up to 4 percent or less), maglev trains can also reduce the need to create new tunnels or to level the landscape to build its tracks.

Records

The highest-recorded maglev speed is 603 kilometres per hour (375 mph), achieved in Japan by JR Central's L0 superconducting maglev on 21 April 2015, 28 kilometres per hour (17 mph) faster than the conventional TGV wheel-rail speed record. However, the operational and performance differences between these two very different technologies is far greater. The TGV record was achieved accelerating down a 72.4 kilometres (45 mi) slight decline, requiring 13 minutes. It then took another 77.25 kilometres (48 mi) for the TGV to stop, requiring a total distance of 149.65 kilometres (93 mi) for the test. The L0 record, however, was achieved on the 42.8 kilometres (26.6 mi) Yamanashi test track – less than 1/3 the distance. No maglev or wheel-rail commercial operation has actually been attempted at speeds over 500 kilometres per hour (310 mph).

History of maglev speed records

Incidents

Two incidents involved fires. A Japanese test train in Miyazaki, MLU002, was completely consumed by a fire in 1991.

On 11 August 2006, a fire broke out on the commercial Shanghai Transrapid shortly after arriving at the Longyang terminal. People were evacuated without incident before the vehicle was moved about 1 kilometre to keep smoke from filling the station. NAMTI officials toured the SMT maintenance facility in November 2010 and learned that the cause of the fire was "thermal runaway" in a battery tray. As a result, SMT secured a new battery vendor, installed new temperature sensors and insulators and redesigned the trays.

On 22 September 2006, a Transrapid train collided with a maintenance vehicle on a test/publicity run in Lathen (Lower Saxony / north-western Germany). Twenty-three people were killed and ten were injured; these were the first maglev crash fatalities. The accident was caused by human error. Charges were brought against three Transrapid employees after a year-long investigation.

Safety is a greater concern with high-speed public transport due to the potential for high impact force and large number of casualties. In the case of maglev trains as well as conventional high-speed rails, an incident could result from human error, including loss of power, or factors outside human control, such as ground movement caused by an earthquake.

Interesting facts about Maglev trains

• The first relevant patent, U.S. Patent 714,851  (2 December 1902), issued to Albert C. Albertson, used magnetic levitation to take part of the weight off of the wheels while using conventional propulsion.
• In 1912 French-American inventor Émile Bachelet demonstrated a model train with electromagnetic levitation and propulsion in Mount Vernon, New York.
• Maglev systems have been much more expensive to construct than conventional train systems, although the simpler construction of maglev vehicles makes them cheaper to manufacture and maintain.
• The Shanghai maglev train, also known as the Shanghai Transrapid, has a top speed of 430 kilometres per hour (270 mph). The line is the fastest operational high-speed maglev train, connecting Shanghai Pudong International Airport and the outskirts of central Pudong, Shanghai. It covers a distance of 30.5 kilometres (19 mi) in just over 8 minutes. The launch in 2002 generated wide public interest and media attention in maglev for the first time.

Images for kids

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  Experimental car TP-05 (ТП-05) in Ramenskoye built in 1986

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  The Birmingham International Maglev shuttle

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  Transrapid at the Emsland test facility

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  HSST-03 at Okazaki Minami Park

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  South Korea's Incheon Airport Maglev, the world's fourth commercially operating maglev

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  Maglev on the Tongji University test track

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  MLX01 Maglev train Superconducting magnet bogie

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  The Japanese SCMaglev's EDS suspension is powered by the magnetic fields induced either side of the vehicle by the passage of the vehicle's superconducting magnets.

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  A maglev train coming out of the Pudong International Airport

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  Linimo train approaching Banpaku Kinen Koen, towards Fujigaoka Station in March 2005

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  Changsha Maglev Train arriving at Langli Station

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  The proposed Melbourne maglev connecting the city of Geelong through Metropolitan Melbourne's outer suburban growth corridors, Tullamarine and Avalon domestic in and international terminals in under 20 min. and on to Frankston, Victoria, in under 30 min.

See also

In Spanish: Tren de levitación magnética para niños

• Hyperloop
• Mass driver