Although the idea of using magnetic levitation in transportation dates back to the beginning of the 20th century, the first MagLev train licensed for passenger transportation was the German Transrapid 05 in 1979. However, the first MagLev train that was open to public was a low-speed MagLev shuttle that connected Birminghams International Airport and Railway station. This service ran for nearly 11 years, but was discontinued because lack of spare parts made it unreliable.
The first operational high-speed MagLev railway was built by Transrapid in Shanghai, China and was inaugurated in 2002. Although all MagLev trains use a Linear Motor for propulsion, different developers use different technology to make the trains levitate. Transrapid trains use a particular MagLev technology known as Electromagnetic Suspension. The bottom of the train wraps around a steel guideway, and have electromagnets fixed to the trains undercarriage. By using the attraction between these electromagnets and the steel guideway, the train manages to levitate about 1cm above the guideway, and can stay this way even when it is not in motion. The trains body is embeded with other electromagnets in order to help stabilise it. Transrapid trains are fixed with a backup power supply in case of a power failure, and thus no wheels or secondary propulsion system are needed. However, a disadvantage of this type of train is that the separation between the train and the guideway must be constantly monitored in order to keep it stabilised. The fastest recorded speed for these trains is 501 km/h. For comparison, the fastest recorded speed for a wheeled train is 574.8 km/h (set by the TGV).
The Transrapid MagLev train in Shanghai is however not the only operational high-speed MagLev railway in the world. As of 2005, Japan Rail has been running an automated MagLev train in Aichi, Japan. JR MagLev trains use different MagLev technology from their German competitors. JR MagLev trains use Electrodynamic Suspension, in which the repulsive properties of magnets are used instead of attraction. These MagLev trains are fixed with super-cooled, superconducting electromagnets which conduct electricity even after the power has been shut off (however, they must be maintained in a super-cooled state in order for the materials to exhibit their electromagnetic properties). The railways used for this kind of MagLev trains are significantly different to those used by Transrapid. The bottom part of the guideway has electromagnets which repel the train forcing it to hover at a height of about 10cm. The guideway also has walls embedded with coils which create magnetic fields which keep the train in place (also by repulsion), and also guide it whenever the guideway bends. These trains are fixed with auxiliary wheels which are needed in order to accelerate the train to a speed at which it is able to levitate. Although this might be seen as a disadvantage, these wheels can help the train to keep in motion in the event of a power failure. However, these trains have one very great disadvantage. Due to the strong magnetic fields of the superconductors, passengers with pacemakers would not be able to board the train unless they travelled in a magnetically shield compartment. The fastest recorded speed for these trains is 581km/h (6 km/h faster than the TGV).
There is a third type of MagLev technology currently in development, known as Stabilized Permanent Magnetic Suspension, in which I believe lies the future of MagLev transportation. This technology uses permanent magnets arranged in a special array called the Halbach array and work in a similar way as the JR MagLev trains with a few key differences. One is that since permanent magnets are used no power is needed to activate the magnets, nor do the magnets require to be maintained in a super-cooled state. This also means that in the event of a power failure the train would slow down smoothly on its own. Also, the magnetic field is concentrated at the bottom of the train, providing safe travel for passengers with pacemakers. These trains are able to hover higher with more stability and thus have the potential to reach faster speeds. Like the JR MagLev trains, these trains require wheels in order for it to move when the vehicle is stopped. However, it is able to hover at merely 5 km/h.
Interesting video:
http://www.geeksaresexy.net/2008/09/23/magnetic-levitation-train/
Loading...
2:15
Do It Yourself Magnetic Levitation! - Part 1by magic76767676574,661 views
Can you build a little hover board with magnets???^^
Fann1MichaelJackson 1 year ago