Two physical forces essential to airplane flight are thrust and lift. Jet engines, such as the elipsis
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MAGLEV, or magnetic levitation, is a system of transportation that suspends, guides and (usually) propels vehicles, predominantly trains, using magnetic forces. This method has the potential to be faster, quieter and smoother than wheeled mass transit systems, potentially reaching velocities comparable to turboprop and jet aircraft (900 km/h, 600 mph).
The highest recorded speed of a maglev train is 581 km/h (361 mph), achieved in Japan in 2003, 6 km/h faster than the conventional TGV speed record.
In the 1970s, Germany and Japan also began research and after some failures both nations developed mature technologies in the 1990s.
Several favourable conditions existed when the link was built:
Development of HSST started in 1974, based on technologies introduced from Germany.In Tsukuba, Japan (1985), the HSST-03 (Linimo) wins popularity in spite of being 30 km/h slower Tsukuba World Exposition. In Okazaki, Japan (1987), the JR-Maglev took a test ride at the Okazaki exhibition. In Saitama, Japan (1988), the HSST-04-1 was revealed at the Saitama exhibition performed in Kumagaya. Its fastest recorded speed was 30 km/h. In Yokohama, Japan (1989), the HSST-05 acquires a business driver's license at Yokohama exhibition and carries out general test ride driving. Maximum speed 42 km/h.
In West Berlin, the M-Bahn was built in the late 1980s. It was a driverless maglev system with a 1.6 km track connecting three stations. Testing in passenger traffic started in August 1989, and regular operation started in July 1991. Although the line largely followed a new elevated alignment, it terminated at the U-Bahn station Gleisdreieck, where it took over a platform that was then no longer in use; it was from a line that formerly ran to East Berlin. After the fall of the Berlin Wall, plans were set in motion to reconnect this line (today's U2). Deconstruction of the M-Bahn line began only two months after regular service began and was completed in February 1992.
The best-known high-speed maglev currently operating commercially is the IOS (initial operating segment) demonstration line of the German built Transrapid train in Shanghai, China that transports people 30 km (18.6 miles) to the airport in just 7 minutes 20 seconds, achieving a top speed of 431 km/h (268 mph), averaging 250 km/h (150 mph).
Other commercially operating lines exist in Japan, such as the Linimo line. Maglev projects worldwide are being studied for feasibility. In Japan at the Yamanashi test track, current maglev train technology is mature, but costs and problems remain a barrier to development. Alternative technologies are being developed to address those issues.
There are two primary types of maglev technology:
Another experimental technology, which was designed, proven mathematically, peer reviewed, and patented, but is yet to be built, is the magnetodynamic suspension (MDS), which uses the attractive magnetic force of a permanent magnet array near a steel track to lift the train and hold it in place.
In electrodynamic suspension (EDS), both the rail and the train exert a magnetic field, and the train is levitated by the repulsive force between these magnetic fields. The magnetic field in the train is produced by either electromagnets (as in JR-Maglev) or by an array of permanent magnets (as in Inductrack). The repulsive force in the track is created by an induced magnetic field in wires or other conducting strips in the track.
At slow speeds, the current induced in these coils and the resultant magnetic flux is not large enough to support the weight of the train. For this reason the train must have wheels or some other form of landing gear to support the train until it reaches a speed that can sustain levitation.
Propulsion coils on the guideway are used to exert a force on the magnets in the train and make the train move forward. The propulsion coils that exert a force on the train are effectively a linear motor: An alternating current flowing through the coils generates a continuously varying magnetic field that moves forward along the track. The frequency of the alternating current is synchronized to match the speed of the train. The offset between the field exerted by magnets on the train and the applied field create a force moving the train forward.
|EMS (Electromagnetic suspension)||Magnetic fields inside and outside the vehicle are insignificant; proven, commercially available technology that can attain very high speeds (500 km/h); no wheels or secondary propulsion system needed||The separation between the vehicle and the guideway must be constantly monitored and corrected by computer systems to avoid collision due to the unstable nature of electromagnetic attraction; due to the system's inherent instability and the required constant corrections by outside systems, vibration issues may occur.|
|EDS (Electrodynamic)||Onboard magnets and large margin between rail and train enable highest recorded train speeds (581 km/h) and heavy load capacity; has recently demonstrated (December 2005) successful operations using high temperature superconductors in its onboard magnets, cooled with inexpensive liquid nitrogen||Strong magnetic fields onboard the train would make the train inaccessible to passengers with pacemakers or magnetic data storage media such as hard drives and credit cards, necessitating the use of magnetic shielding; limitations on guideway inductivity limit the maximum speed of the vehicle; vehicle must be wheeled for travel at low speeds.|
|Inductrack System (Permanent Magnet EDS)||Failsafe Suspension - no power required to activate magnets; Magnetic field is localized below the car; can generate enough force at low speeds (around 5 km/h) to levitate maglev train; in case of power failure cars slow down on their own safely; Halbach arrays of permanent magnets may prove more cost-effective than electromagnets||Requires either wheels or track segments that move for when the vehicle is stopped. New technology that is still under development (as of 2008) and as yet has no commercial version or full scale system prototype.|
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 these systems. EMS systems are wheel-less.
The German Transrapid, Japanese HSST (Linimo), and Korean Rotem EMS maglevs levitate at a standstill, with electricity extracted from guideway using power rails for the latter two, and wirelessly for Transrapid. 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.
Because Maglev vehicles essentially fly, stabilisation of pitch, roll and yaw is required by magnetic technology. In addition translations, surge (forward and backward motions), sway (sideways motion) or heave (up and down motions) can be problematic with some technologies.
Due to the lack of physical contact between the track and the vehicle, maglev trains experience no rolling friction, leaving only air resistance and electromagnetic drag, potentially improving power efficiency.
The weight of the large electromagnets in EMS and EDS designs is a major design issue. A very strong magnetic field is required to levitate a massive train. For this reason one research path is using superconductors to improve the efficiency of the electromagnets.
Though they are relatively quiet at low speeds, the high speed of some maglev trains causes large air displacement, which corresponds to significant noise pollution. A study found that high speed maglev trains are 5 dB noisier than traditional trains. However, two trains passing at a combined 1,000 km/h has been successfully demonstrated without major problems in Japan.
Braking issues and overhead wire wear are problems for the Fastech 360 railed Shinkansen. Maglev would eliminate these issues.
Issues relating to magnets are also a factor. See suspension types.
As linear motors must fit within or straddle their track over the full length of the train, track design is challenging for anything other than point-to-point services. Curves must be gentle, while switches are very long and need care to avoid breaks in current.
Maglev needs very fast-responding control systems to maintain a stable height above the track; this needs careful design in the event of a failure in order to avoid crashing into the track during a power fluctuation.
For many systems, it is possible to define a lift-to-drag ratio. These ratios can exceed that of aircraft (for example Inductrack can approach 200:1 at high speed, far higher than any aircraft). This can make it more efficient per mile, and potentially give greater range.
Aircraft travel at high altitude where the airdrag is lower, and hence can travel faster, and can service more destinations.
Maglev can transport larger numbers of people far more efficiently in large urban areas. Unlike airports, one need not arrive early at the train stations to go through numerous security checks.
China aims to limit the cost of future construction extending the maglev line to approximately 200 million yuan (US$24.6 million) per kilometer. These costs compare competitively with airport construction (e.g., Hong Kong Airport cost US$20 billion to build in 1998) and eight-lane Interstate highway systems that cost around US$50 million per mile (US$31 million per kilometer) in the US.
While high-speed maglevs are expensive to build, they are less expensive to operate and maintain than traditional high-speed trains, planes or intercity buses. Data from the Shanghai maglev project indicates that operation and maintenance costs are covered by the current relatively low volume of 7,000 passengers per day. Passenger volumes on the Pudong International Airport line are expected to rise dramatically once the line is extended from Longyang Road metro station all the way to Shanghai's downtown train depot.
The proposed Chūō Shinkansen maglev in Japan is estimated to cost approximately US$82 billion to build, with a route blasting long tunnels through mountains. A Tokaido maglev route replacing current Shinkansen would cost some 1/10th the cost, as no new tunnel blasting would be needed, but noise pollution issues would make it infeasible.
The only low-speed maglev (100 km/h) currently operational, the Japanese Linimo HSST, cost approximately US$100 million/km to build. Besides offering improved operation and maintenance costs over other transit systems, these low-speed maglevs provide ultra-high levels of operational reliability and introduce little noise and zero air pollution into dense urban settings.
As maglev systems are deployed around the world, experts expect construction costs to drop as new construction methods are perfected.
Transrapid, a German maglev company, has a test track in Emsland with a total length of 31.5 km (19.6 mi). The single track line runs between Dörpen and Lathen with turning loops at each end. The trains regularly run at up to 420 km/h (261 mph). The construction of the test facility began in 1980 and finished in 1984.
Japan has a demonstration line in Yamanashi prefecture where test trains JR-Maglev MLX01 have reached 581 km/h (361 mph), slightly faster than any wheeled trains (the current TGV speed record is 574.8 km/h, 357.0 mph).
These trains use superconducting magnets which allow for a larger gap, and repulsive-type electrodynamic suspension (EDS). In comparison Transrapid uses conventional electromagnets and attractive-type electromagnetic suspension (EMS). These "Superconducting Maglev Shinkansen", developed by the Central Japan Railway Company (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. Yamanashi Prefecture residents (and government officials) can sign up to ride this for free, and some 100,000 have done so already.
The world's first commercial automated "Urban Maglev" system commenced operation in March 2005 in Aichi, Japan. This is the nine-station 8.9 km long Tobu-kyuryo Line, otherwise known as the Linimo. 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 was made by Rotem ans is now under operation in Daejeon.
Transrapid, in Germany, constructed the first operational high-speed conventional maglev railway in the world, the Shanghai Maglev Train from downtown Shanghai (Shanghai Metro) to the Pudong International Airport. 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. The plan for the Shanghai-Hangzhou Maglev Train was approved by the central government in February 2006, with plans for completion by 2010.
London – Glasgow: A maglev line was recently proposed in the United Kingdom from London to Glasgow with several route options through the Midlands, Northwest and Northeast of England and was reported to be under favourable consideration by the government. But the technology was rejected for future planning in the Government White Paper Delivering a Sustainable Railway published on July 24, 2007. Another high speed link is being planned between Glasgow and Edinburgh but there is no settled technology for it.
In proposing a maglev system, its improved life and performance over mechanical engines were cited as important factors, as well as improving comfort, safety, economics and environmental impact over conventional rail.
However the extension has not been universally welcomed; in January and February 2008 hundreds of residents demonstrated in downtown Shanghai against the line being built too close to their homes, citing concerns about sickness due to exposure to the strong magnetic field, noise, pollution and devaluation of property near to the lines.
China also intends to build a factory in Nanhui district to produce low-speed maglev trains for urban use.
State of Maharashtra has also approved feasibility study for Maglev train between Mumbai, which is commercial capital of India and state govt capital and Nagpur, which is second capital of the state and about 1000 km away. It plans to connect developed area of Mumbai and Pune with Nagpur via underdeveloped hinterland via Ahmednagar, Beed, Latur, Nanded and Yavatmal.
The consortium is to invest an 85% of the total cost of $US 650 million. The 5m-high guideway will be built from the Lahore Bridge on the river Ravi near Shahdara, via Bhatti Chowk to the new terminals. The stations, 26 of which have been identified, will be accessed from street level by stairs initially and lifts at a later date. With a commercial speed of 60 km/h, journey time will be 31 minutes, which is about half the time it takes by road. A further study has been initiated on the project.
Since the federal government decision, private groups from Nevada have proposed a line running from Las Vegas to Los Angeles with stops in Primm, Nevada; Baker, California; and points throughout San Bernardino County into Los Angeles. Southern California politicians have not been receptive to these proposals; many are concerned that a high speed rail line out of state would drive out dollars that would be spent in state "on a rail" to Nevada.
Baltimore-Washington D.C. Maglev: A 64 km project has been proposed linking Camden Yards in Baltimore and Baltimore-Washington International (BWI) Airport to Union Station in Washington, D.C. It is in demand for the area due to its current traffic/congestion problems.
The Pennsylvania Project: The Pennsylvania High-Speed Maglev Project corridor extends from the Pittsburgh International Airport to Greensburg, with intermediate stops in downtown Pittsburgh and Monroeville. This initial project will serve a population of approximately 2.4 million people in the Pittsburgh metropolitan area. The Baltimore proposal is competing with the Pittsburgh proposal for a $90 million federal grant. The point of the project is to see if the maglev system can function properly in a U.S. city environment.
San Diego-Imperial County airport: In 2006 San Diego commissioned a study for a maglev line to a proposed airport located in Imperial County. SANDAG says that the concept would be an "airports without terminals", allowing passengers to check in at a terminal in San Diego ("satellite terminals") and take the maglev to Imperial airport and board the airoplane there as if they went directly through the terminal in the Imperial location. In addition, the maglev would have the potential to carry high priority freight. Further studies have been requested although no funding has yet been agreed.
Atlanta – Chattanooga: The proposed maglev route would run from Hartsfield-Jackson Atlanta International Airport, run through Atlanta, continue to the northern suburbs of Atlanta, and possibly even extend to Chattanooga, Tennessee. If built, the maglev line would rival Atlanta's current subway system, the Metropolitan Atlanta Rapid Transit Authority (MARTA), the rail system of which includes a major branch running from downtown Atlanta to Hartsfield-Jackson airport.
On March 27, 2008, the German Transport minister announced the project had been canceled due to rising costs associated with constructing the track. A new estimate put the project between 3.2 and 3.4 billion euros.
On August 11, 2006 a fire broke out on the Shanghai commercial Transrapid, shortly after leaving the terminal in Longyang.
On September 22, 2006 an elevated Transrapid train collided with a maintenance vehicle on a test run in Lathen (Lower Saxony / north-western Germany). Twenty-three people were killed and ten were injured. These were the first fatalities resulting from a Maglev train accident. The accident was caused by a security concept without tolerance for human error.