Maglev (derived from magnetic levitation) is a transport method that uses magnetic levitation to move vehicles without touching the ground. With maglev, a vehicle travels along a guideway using magnets to create both lift and propulsion, thereby reducing friction by a great extent and allowing very high speeds.
The Shanghai Maglev Train, also known as the Transrapid, is the fastest commercial train currently in operation and has a top speed of 430 km/h (270 mph). The line was designed to connect Shanghai Pudong International Airport and the outskirts of central Pudong, Shanghai. It covers a distance of 30.5 kilometers (19.0 mi) in 8 minutes.
Maglev trains move more smoothly and more quietly than wheeled mass transit systems. They are relatively unaffected by weather. The power needed for levitation is typically not a large percentage of its overall energy consumption; most goes to overcome drag, as with other high-speed transport. Maglev trains hold the speed record for trains.
Compared to conventional trains, differences in construction affect the economics of maglev trains, making them much more efficient. For high-speed trains with wheels, wear and tear from friction along with dynamic augment from wheels on rails accelerates equipment wear and prevents high speeds. Conversely, maglev systems have been much more expensive to construct, offsetting lower maintenance costs.
Despite decades of research and development, only three commercial maglev transport systems are in operation, while one more is under construction. In April 2004, Shanghai’s Transrapid system began commercial operations. In March 2005, Japan began operation of its relatively low-speed HSST “Linimo” line in time for the 2005 World Expo. In its first three months, the Linimo line carried over 10 million passengers. South Korea became the world’s fourth country to succeed in commercializing maglev technology with the Incheon Airport Maglev beginning commercial operation on February 3, 2016.
TYPES OF MAGLEV TRAINS
The two notable types of maglev technology are:
Electromagnetic Suspension System:
In electromagnetic suspension (EMS) systems, the train levitates above a steel rail while electromagnets, attached to the train, are oriented toward the rail from below. The system is typically arranged on a series of C-shaped arms, with the upper portion of the arm attached to the vehicle, and the lower inside edge containing the magnets. The rail is situated inside the C, between the upper and lower 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 millimetres (0.59 in)).
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.
The highest recorded maglev speed is 603 km/h (375 mph), achieved in Japan by JR Central’s L0 superconducting Maglev on 21 April 2015, 28 km/h (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 km (45.0 mi) slight decline, requiring 13 minutes. It then took another 77.25 km (48.00 mi) for the TGV to stop, requiring a total distance of 149.65 km (92.99 mi) for the test. The MLX01 record, however, was achieved on the 18.4 km (11.4 mi) Yamanashi test track – 1/8 the distance. No maglev or wheel-rail commercial operation has actually been attempted at speeds over 500 km/h.
Reference: https://en.wikipedia.org/wiki/Maglev — edited by An-Nuur Press Agency