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Model Superconducting Maglev Train November 5, 2006

Posted by Unreasonable in Matters Scientific, Matters Technological.

It looks like they’re using a superconducting magnet to levitate the train.

Metals are a lattice of atoms. The electrons of those atoms are loosely bound, and they exchange easily between atoms within the lattice. That electron flow is the reason that metals conduct heat and electricity so well. However, at room temperature, those electrons bang into one another occasionally, and the energy from the collisions is dissipated as waste heat. That inefficiency results in resistance to electrical flow.

In 1911, a dutch physicist discovered that when some metals are cooled to near absolute zero, the electrons continue to move, but they magically stop banging together. The inefficiency virtually disappears, so there is almost no energy lost. Even more bizarrely, ceramics, which are normally insulators because they don’t allow electron flow, also turn into superconductors at low temps. When a magnet is cooled to superconductor state, the electromagnetic field is extremely strong, and because the inefficiency is almost gone the field lasts an extremely long time without any energy input.

Maglev trains use the repulsion between magnets in the train and magnets in the track to levitate it above the track. Another set of electromagnets in each section of track are used for propulsion. They powered on and off in sequence to pull the train forward.

Currently, electromagnets are used for both propulsion and levitation, but superconducting levitation systems are under development. The first maglev began carrying people 19 miles from Shanghai to the Pudong Airport (Google Map) in 2003. Top speed is about 300 mph. A round-trip ticket is $10 US. The train was manufactured by Transrapid, a German consortium consisting mainly of Siemens and ThyssenKrupp.

Transrapid has a test track in Germany (Google Map), and the Germans are planning a maglev of their own for the Munich Airport, but so far, I don’t think they have one operating for the public.

::How Maglev Trains Work ::History of Superconductors ::Shanghai Maglev Pics

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