Magnetic levitation (maglev) is a highly advanced technology. It is used in the various cases, including clean energy (small and huge wind turbines: at home, office, industry, etc.), building facilities (fan), transportation systems (magnetically levitated train, Personal Rapid Transit (PRT), etc.), weapon (gun, rocketry), nuclear engineering (the centrifuge of nuclear reactor), civil engineering (elevator), advertising (levitating everything considered inside or above various frames can be selected), toys (train, levitating spacemen over the space ship, etc.), stationery (pen) and so on. The common point in all these applications is the lack of contact and thus no wear and friction. This increases efficiency, reduce maintenance costs and increase the useful life of the system. The magnetic levitation technology can be used as a highly advanced and efficient technology in the various industrial. There are already many countries that are attracted to maglev systems.
Among above-cited beneficial usages, the most crucial utilization of magnetic levitation is in operation of magnetically levitated trains. Magnetically levitated trains are certainly the maximum superior motors presently to be had to railway industries. Maglev is the first essential innovation within the area of railroad generation because the invention of the railroad. Magnetically levitated train is a highly modern vehicle. Maglev vehicles use noncontact magnetic levitation, guidance and propulsion systems and have no wheels, axles and transmission. Contrary to traditional railroad vehicles, there is no direct physical contact between maglev vehicle and its guide way. These vehicles move along magnetic fields that are established between the vehicle and its guide way. Conditions of no mechanical contact and no friction provided by such technology makes it feasible to reach higher speeds of travel attributed to such trains. Manned maglev vehicles have recorded speed of travel equal to 581km/hr. The replacement of mechanical components by wear-free electronics overcomes the technical restrictions of wheel-on-rail technology. Application of magnetically levitated trains has attracted numerous transportation industries throughout the world. Magnetically levitated trains are the most recent advancement in railway engineering specifically in transportation industries. Maglev trains can be conveniently considered as a solution for transportation needs of the current time as well as future needs of the world. There is variety of designs for maglev systems and engineers keep revealing new ideas about such systems. Many systems have been proposed in different parts of the worlds, and a number of corridors have been selected and researched.1
Rapid growth of populations and the never ending demand to increase the speed of travel has always been a dilemma for city planners. The future is already here. Rapid transit and high-speed trains have always been thought of and are already in use. This is the way further into the future. Trains with magnetic levitations are part of the game. Conventional railway systems have been modified to make them travel at much higher speeds. Also, variety of technologies including magnetic levitation systems and high-speed railway (HSR) systems has been introduced. Rapid development of transportation industries worldwide, including railroads and the never ending demand to shorten travel time during trade, leisure, etc. have caused planning and implementation of high-speed railroads in many countries. Variety of such systems including maglev has been introduced to the industry. Maglev trains are a necessity for modern time transportation needs and vital for the future needs of railways, worldwide. This has resulted in the development of a variety of maglev systems that are manufactured by different countries. Maglev systems currently in use have comparable differences. The current models are also changing and improving.
Industries have to grow in order to facilitate many aspects of modern day life. This comes with a price to pay for by all members of societies. Industrial developments and widespread use of machineries have also increased risks of financial damages and loss of lives. Safety and needs to physically protect people against machineries may have not been a priority in the past but they are necessities of modern times. Experts of industries have the task of solving safety and protection issues before implementing machineries. This is a step with high priority for all industrial assignments. While being fast, reliable and comfortable, maglev systems have found special places in minds of people. Running at such high speeds, maglev systems have to be safe and need to be renown for safety. This puts much heavier loads on the shoulders of the corresponding experts and managers, compared to some other means of transportation. Safety is knowingly acting with proper functions to provide comfort and reduce dangers, as much as possible. Risk management techniques have a vital role in organizing and implementing proper acts during incidents, accidents or mishaps in maglev systems operations. Effective management has a specific place in such processes. Obviously, such plannings put considerable financial load on the system. Implementation of internationally accepted standards is a fundamental step toward uplifting track safety. It will also serve to improve route quality, increase passenger loads and increase speed of travel. Maglev vehicle is one of the important transportation equipment of the urban track traffic system toward the future.
The ordinary plan for research and development and application of maglev generation ought to be made at the country wide stage. This plan shall consist of the improvement plans as to research and improvement of key maglev era, project imposing generation research and improvement of maglev venture, plans of building maglev passage based totally on visitors demands, investment and financing system for the construction and operation of maglev device, research on imposing plans of high-density operational enterprise and protection of maglev route and so on.
It is very important to be vigilant about economical aspects of any major project during its planning and construction phases. Optimal use of local resources must be all accounted for. Technical and economical evaluation of the projects is a necessity to their success. It is necessary to have prior knowledge for investing into a project and then implementing its goals. Good planning makes it feasible to run the projects with reduced risks and increased return for the investment.2
2.1 First Maglev patent
High-speed transportation patents were granted to various inventors throughout the world. Early United States patents for a linear motor propelled train were awarded to German inventor Alfred Zehden. The inventor was awarded U.S. Patent 782,312(14 February 1905) and U.S. Patent RE12,700 (21 August 1907). In 1907, another early electromagnetic transportation system was developed by F. S. Smith.A series of German patents for magnetic levitation trains propelled by linear motors were awarded to Hermann Kemper between 1937 and 1941. An early maglev train was described in U.S. Patent 3,158,765, “Magnetic system of transportation”, by G. R. Polgreen (25 August 1959). The first use of “maglev” in a United States patent was in “Magnetic levitation guidance system”, by Canadian Patents and Development Limited.3
2.2 New York, United States, 1968
In 1968, even as behind schedule in visitors on the Throgs Neck Bridge, James Powell, a researcher at Brookhaven National Laboratory (BNL), notion of the usage of magnetically levitated transportation. Powell and BNL colleague Gordon Danby labored out a MagLev concept the use of static magnets mounted on a transferring car to set off electro dynamic lifting and stabilizing forces in specially shaped loops, together with figure of eight coils on a manual manner.
2.3 Hamburg, Germany, 1979
Transrapid 05 was the first maglev train with long stator propulsion licensed for passenger transportation. In 1979, a 908 m (2,979 ft) track was opened in Hamburg for the first International Transportation Exhibition (IVA 79). Interest was sufficient that operations were extended three months after the exhibition finished, having carried more than 50,000 passengers. It was reassembled in Kassel in 1980.
2.4 Birmingham, United Kingdom, 1984–95
The world’s first commercial maglev system was a low-speed maglev shuttle that ran between the airport terminal of Birmingham International Airport and the nearby Birmingham International railway station between 1984 and 1995. Its track length was 600 m (2,000 ft), and trains levitated at an altitude of 15 mm (0.59 in), levitated by electromagnets, and propelled with linear induction motors. It operated for 11 years and was initially very popular with passengers, but obsolescence problems with the electronic systems made it progressively unreliable as years passed, leading to its closure in 1995. One of the original cars is now on display at Rail world in Peterborough, together with the RTV31 hover train vehicle. Another is on display at the National Railway Museum in York.
Several favourable conditions existed when the link was built:
• The British Rail Research vehicle was 3 tonnes and extension to the 8 tonne vehicle was easy.
• Electrical power was available.
• The airport and rail buildings were suitable for terminal platforms.
• Only one crossing over a public road was required and no steep gradients were involved.
• Land was owned by the railway or airport.
• Local industries and councils were supportive.
• Some government finance was provided and because of sharing work, the cost per organization was low.
After the system closed in 1995, the original guide way lay dormant14 until 2003, when a replacement cable-hauled system, the Air Rail Link Cable Liner people mover, was opened.
2.5 Emsland, Germany, 1984–2012
Transrapid, a German maglev company, had a test track in Emsland with a total length of 31.5 km (19.6 mi). The single-track line ran between Dörpen and Lathen with turning loops at each end. The trains regularly ran at up to 420 km/h (260 mph). Paying passengers were carried as part of the testing process. The production of the test facility started in 1980 and finished in 1984. In 2006, the Lathen maglev educate coincidence took place killing 23 human beings, found to were resulting from human mistakes in imposing protection checks. From 2006 no passengers were carried. At the end of 2011 the operation licence expired and changed into no longer renewed, and in early 2012 demolition permission turned into given for its centers, such as the song and manufacturing facility.
2.6 Japan, 1969–present
Japan operates two independently developed maglev trains. One is HSST (and its descendant, the Linimo line) by Japan Airlines and the other, which is more wellknown, is SCMaglev by the Central Japan Railway Company.
The development of the latter started in 1969. Miyazaki test track regularly hit 517 km/h (321 mph) by 1979. After an accident that destroyed the train, a new design was selected. In Okazaki, Japan (1987), the SCMaglev took a test ride at the Okazaki exhibition. Tests through the 1980s continued in Miyazaki before transferring to a far larger test track, 20 km (12 mi) long, in Yamanashi in 1997.
Development of HSST started in 1974. In Tsukuba, Japan (1985), the HSST-03 (Linimo) became popular in spite of its 30 km/h (19 mph) at the Tsukuba World Exposition. In Saitama, Japan (1988), the HSST-04-1 was revealed at the Saitama exhibition performed in Kumagaya. Its fastest recorded speed was 300 km/h (190 mph).
2.7 Vancouver, Canada and Hamburg, Germany, 1986–88
In Vancouver, Canada, the HSST-03 by HSST Development Corporation (Japan Airlines and Sumitomo Corporation) was exhibited at Expo 8619 and ran on a 400-metre (0.25 mi) test track that provided guests with a ride in a single car along a short section of track at the fairgrounds. It was removed after the fair and debut at the Aoi Expo in 1987 and now on static display at Okazaki Minami Park. In Hamburg, Germany, the TR-07 was exhibited at the international traffic exhibition (IVA88) in 1988.
2.8 Berlin, Germany, 1989–91
In West Berlin, the M-Bahn was built in the late 1980s. It was a driverless maglev system with a 1.6 km (0.99 mi) track connecting three stations. Testing with 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 Gleisdreieck U-Bahn station, where it took over an unused platform for 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.
2.9 South Korea, 1993–present
In 1993, Korea completed the development of its own maglev train, shown off at the Taejon Expo ’93, which was developed further into a full-fledged maglev capable of travelling up to 110 km/h (68 mph) in 2006. This final model was incorporated in the Incheon Airport Maglev which opened on February 3, 2016, making Korea the world’s fourth country to operate its own self-developed maglev after the United Kingdom’s Birmingham International Airport, Germany’s Berlin M-Bahn, and Japan’s Linimo. It links Incheon International Airport to the Yongyu Station and Leisure Complex on Yeongjong island. It offers a transfer to the Seoul Metropolitan Subway at AREX’s Incheon International Airport Station and is offered free of charge to anyone to ride, operating between 9 am and 6 pm with 15 minute intervals. Operating hours are to be raised in the future.
The maglev system was co-developed by the Korea Institute of Machinery and Materials (KIMM) and Hyundai Rotem. It is 6.1 kilometers (3.8 mi) long, with six stations and a 110 km/h (68 mph) operating speed.4
3.1 Basic Idea
A common type of magnet is a dipole. It has North Pole (N) and South Pole (S). Principle of magnetism simply states that like poles repel and opposite poles attract. Maglev uses the same principle to lift the train above the guide way. However, the magnetic field in this case is not entirely coming from permanent magnets, but it is created by electric current that is induced through the train and guide way. It creates temporary magnetic force and temporary magnetic poles. Also, Maglev uses the principle of linear induction and magnetism to propel the train forward or backward. The combination of repulsive and attractive magnetic forces causes the train to levitate and pass ahead. When the contemporary changes route, the poles additionally trade and the repulsive and appealing forces act opposite from whilst the movement commenced. It reasons the teach to move backward. Generally, Maglev will be operated functionally if it goes thru these three tactics; levitation, propulsion and steering.5
3.2 The two notable types of maglev technology are:
3.2.1 Electromagnetic suspension (EMS)
If you’ve ever played with magnets, you know that opposite poles attract and like poles repel each other. This is the basic principle behind electromagnetic propulsion. Electromagnets are similar to other magnets in that they attract metal objects, but the magnetic pull is temporary. As you can read about in How Electromagnets Work, you can easily create a small electromagnet yourself by connecting the ends of a copper wire to the positive and negative ends of an AA, C or D-cell battery. This creates a small magnetic field. If you disconnect either end of the wire from the battery, the magnetic field is taken away.
The magnetic field created in this wire-and-battery experiment is the simple idea behind a maglev train rail system. There are three components to this system:
• A large electrical power source
• Metal coils lining a guideway or track
• Large guidance magnets attached to the underside of the train
The big difference between a maglev train and a conventional train is that maglev trains do not have an engine at least not the kind of engine used to pull typical train cars along steel tracks. The engine for maglev trains is rather inconspicuous. Instead of using fossil fuels, the magnetic field created by the electrified coils in the guideway walls and the track combines to propel the train.
In electromagnetic suspension (EMS) structures, the educate levitates above a steel rail at the same time as electromagnets, attached to the educate, are oriented toward the rail from beneath. The gadget is normally arranged on a series of C-formed palms, with the higher part of the arm attached to the car, and the lower interior side containing the magnets. The rail is situated in the C, between the higher and decrease edges.
Magnetic attraction varies inversely with the cube of distance, so minor changes in distance between the magnets and the rail produce greatly varying forces. These changes in force are dynamically unstable – a slight divergence from the optimum position tends to grow, requiring sophisticated feedback systems to maintain a constant distance from the track, (approximately 15 mm (0.59 in)).
The major advantage to suspended maglev systems is that they work at all speeds, unlike electrodynamic systems, which only work at a minimum speed of about 30 km/h (19 mph). This eliminates the need for a separate low-speed suspension system, and can simplify track layout. On the downside, the dynamic instability demands fine track tolerances, which can offset this advantage. Eric Laithwaite was concerned that to meet required tolerances, the gap between magnets and rail would have to be increased to the point where the magnets would be unreasonably large. In practice, this problem was addressed through improved feedback systems, which support the required tolerances.6
18.104.22.168 The Maglev Track
The magnetized coil running along the track, called a guideway, repels the large magnets on the train’s undercarriage, allowing the train to levitate between 0.39 and 3.93 inches (1 to 10 cm) above the guideway. Once the train is levitated, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway. The electric current supplied to the coils in the guideway walls is constantly alternating to change the polarity of the magnetized coils. This change in polarity causes the magnetic field in front of the train to pull the vehicle forward, while the magnetic field behind the train adds more forward thrust.
Maglev trains float on a cushion of air, casting off friction. This loss of friction and the trains’ aerodynamic designs allow those trains to reach unheard of ground transportation speeds of extra than 310 mph (500 kph), or two times as rapid as Amtrak’s fastest commuter educate. In evaluation, a Boeing-777 commercial plane used for longrange flights can attain a top pace of approximately 562 mph (905 kph). Developers say that maglev trains will ultimately hyperlink cities that are up to 1,000 miles (1,609 km) aside. At 310 mph, you could travel from Paris to Rome in just over hours.
Germany and Japan are both developing maglev train technology, and both are currently testing prototypes of their trains. (The German company “Transrapid International” also has a train in commercial use — more about that in the next section.) Although based on similar concepts, the German and Japanese trains have distinct differences. In Germany, engineers have developed an electromagnetic suspension (EMS) system, called Transrapid. In this system, the bottom of the train wraps around a steel guideway. Electromagnets attached to the train’s undercarriage are directed up toward the guideway, which levitates the train about 1/3 of an inch (1 cm) above the guideway and keeps the train levitated even when it’s not moving. Other guidance magnets embedded in the train’s body keep it stable during travel. Germany has demonstrated that the Transrapid maglev train can reach 300 mph with people onboard.7
3.2.2 Electrodynamic suspension (EDS)
Japanese engineers are developing a competing version of maglev trains that use an electrodynamic suspension (EDS) system, which is based on the repelling force of magnets. The key difference between Japanese and German maglev trains is that the Japanese trains use super-cooled, superconducting electromagnets. This kind of electromagnet can conduct electricity even after the power supply has been shut off. In the EMS system, which uses standard electromagnets, the coils only conduct electricity when a power supply is present. By chilling the coils at frigid temperatures, Japan’s system saves energy. However, the cryogenic system uses to cool the coils can be expensive.
Another difference between the systems is that the Japanese trains levitate nearly 4 inches (10 cm) above the guideway. One potential drawback in using the EDS system is that maglev trains must roll on rubber tires until they reach a liftoff speed of about 62 mph (100 kph). Japanese engineers say the wheels are an advantage if a power failure caused a shutdown of the system. Germany’s Transrapid train is equipped with an emergency battery power supply. Also, passengers with pacemakers would have to be shielded from the magnetic fields generated by the superconducting electromagnets.
In electrodynamic suspension (EDS), both the guideway and the train exert a magnetic field, and the train is levitated by the repulsive and attractive force between these magnetic fields. In some configurations, the train can be levitated only by repulsive force. In the early stages of maglev development at the Miyazaki test track, a purely repulsive system was used instead of the later repulsive and attractive EDS system. The magnetic field is produced either by superconducting magnets (as in JR–Maglev) or by an array of permanent magnets (as in Inductrack). The repulsive and attractive force in the track is created by an induced magnetic field in wires or other conducting strips in the track. A major advantage of EDS maglev systems is that they are dynamically stable – changes in distance between the track and the magnets creates strong forces to return the system to its original position. In addition, the attractive force varies in the opposite manner, providing the same adjustment effects. No active feedback control is needed.
However, at slow speeds, the modern brought on in those coils and the ensuing magnetic flux isn’t always massive enough to levitate the teach. For this motive, the educate should have wheels or some different shape of touchdown equipment to support the teach till it reaches take-off pace. Since a educate can also prevent at any region, because of equipment troubles as an instance, the whole tune need to be able to help each low- and excessive-velocity operation.
Another downside is that the EDS system naturally creates a field in the track in front and to the rear of the lift magnets, which acts against the magnets and creates magnetic drag. This is generally only a concern at low speeds (This is one of the reasons why JR abandoned a purely repulsive system and adopted the sidewall levitation system.) At higher speeds other modes of drag dominate.
The drag force can be used to the electrodynamic system’s advantage, however, as it creates a varying force in the rails that can be used as a reactionary system to drive the train, without the need for a separate reaction plate, as in most linear motor systems. Laithwaite led development of such “traverse-flux” systems at his Imperial College laboratory. Alternatively, 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 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 creates a force moving the train forward.8
3.2.3 Pros and Cons of Electromagnetic suspension (EMS) and Electrodynamic suspension (EDS)
Technology Pros Cons
Electromagnetic suspension (EMS). Magnetic fields inside and outside the vehicle are less than EDS; proven, commercially available technology; high speeds (500 km/h or 310 mph); no wheels or secondary propulsion system needed. The separation between the vehicle and the guide way must be constantly monitored and corrected due to the unstable nature of electromagnetic attraction; to the system’s inherent instability and the required constant corrections by outside systems may induce vibration.
Electrodynamic suspension (EDS). Onboard magnets and large margin between rail and train enable highest recorded speeds (603 km/h or 375 mph) and heavy load capacity; demonstrated successful operations using high temperature superconductors in its onboard magnets, cooled with inexpensive liquid nitrogen. Strong magnetic fields on the train would make the train unsafe for passengers with pacemakers or magnetic data storage media such as hard drives and credit cards, necessitating the use of magnetic shielding; limitations on guide way inductivity limit maximum speed; vehicle must be wheeled for travel at low speeds.
Table 1: Pros and Cons of Electromagnetic suspension (EMS) and Electrodynamic suspension (EDS)
3.3 The three primary functions in maglev technology
It is important for the train to be able to stay suspended above the guideway so that Maglev can be operated. There are two important type of levitation:
• Electromagnetic Suspension (EMS)
• Electrodynamic Suspension (EDS)
22.214.171.124 Electromagnetic Suspension (EMS)
This system is arranged on a series of C-shaped arms. Upper part of the arm is attached to the vehicle (the train) and lower inside edge of the arm contains the electromagnet coil. The guideways is placed inside the arm with another electromagnet coil is attached at the bottom of it. The two coils with opposite poles are facing each other and create an attractive force as shown in Figure 17. Then, the attractive force causes the train to be pushed upward and thus, levitate. However, the magnetic attraction varies inversely with cube of distance. It means a slight distance changes between the train and the guide way, will produce a significantly varying force. So, a feedback system is created to maintain the optimum distance (approximately 15mm or 0.59in) between the train and the guide way.9
Figure 17: Levitation in Electromagnetic Suspension (EMS)
126.96.36.199 Electro dynamic Suspension (EDS)
In this system, both the train and the guide way exert magnetic fields. The train is levitated by repulsive and attractive forces between these magnetic fields. These magnetic fields are created by superconducting magnets that are attached to the train and the guide way. Looking at Figure 18, the repulsive and attractive force is created by the induced magnetic field in the conducting coils in the system. Nonetheless, at slower speed (below 30 km/h or 19 mph), current induced in this coils and resultant magnetic flux are not large enough to levitate the train. So, wheels or other form of landing gears are installed to support the train until it reaches the take-off speed.10
In order for the train to move, a force that drives it forward is needed. Generally, a Maglev train does not have an engine. It uses electric linear motor to achieved propulsion. A normal motor will have a stator and a rotor. A stator is used to generate rotating magnetic field that induced rotating force on a rotor. As a result, the rotor will rotate. Likewise, linear motor is like an unrolled version of the normal motor as shown in Figure 19. In this motor, instead of having a rotating magnetic field, the stator creates the magnetic field across its length. Therefore, the rotor will experience a linear force that is pulled across the stator making the rotor moves forward in straight line.
The concept is applied to the Maglev train. In this case, the train is the rotor and the guide way is the stator. As long as the guide way is induced with magnetic field, the train will move along its track. This system is called Linear Induction Motor (LIM). However, this system causes the train to be lag behind the guide way’s moving field and results in speed and energy losses. So, a new system called Linear Synchronous Motor (LSM) is introduced. The lag is removed by attaching a permanent magnet to the train to create its own static magnetic field. With addition of the magnet, the train travel in synchronize with the moving field. For a long run in traction, LIM is preferred and for short run, LSM is preferred.10
Guidance is vital to preserve the train to be focused over the guideway and save you lateral displacement. Guidance gadget normally makes use of repulsive magnetic pressure to attain the placement intended. However, one of a kind levitation device has a distinct steering.
188.8.131.52 Electromagnetic Suspension (EMS)
In this system, two electromagnetic coils are placed on the train, facing the sides of the guideways as shown in Figure 21. Repulsive magnetic force from both sides of the train keep the vehicle laterally on the guideway. Gap sensors are installed to detect changes in gap width so the current supplied to the guideway can be adjusted accordingly, allowing the train to shift back to the center.
184.108.40.206 Electro dynamic Suspension (EDS)
In this system, guidance is coupled in the levitation system. Looking at Figure 22, propulsion coils are set on the left and right side of the guideway. When the train runs in the center of the guideway, induced electromotive force (EMF) cancel each other out. Through this connection, if the train moves closer to either side of the guideway, circulating current between these two coils is induced; as result, it creates a force that will push the train back to the center.10