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Q & A: levitating trains

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Most recent answer: 10/22/2007
Q:
I am planning to build a magnetically levitated train for my senior science fair project and I was wondering if I can use permanent magnets (neodymium) for the track. Their poles will be alternated so they will look something like this: N S N S N S N S S N S N S N S N and then I will use electromagnets on the train itself which can be turned on and off to propel the train. This is just an idea of mine and I was wondering if it would work? Or do I have to use electromagnets on both the track and the train to get the train to move?
- Eddie (age 17)
Ohio
A:
I don't see why you would need electromagnets on both tracks and train. Electromagnets on just one would be easier and still allow the forces to be switched electrically.

You probably already know that no set of fixed magnets can even levitate the train, even if you forget about propulsion. You either need some strong diamagnet (only superconductors, in practice) or a careful feedback switching circuit on those electromagnets to keep the train levitating.

You can also install wheels and guide rails to keep the train from sliding off sideways, but this defeats the purpose a bit of having magnetic levitation, which minimizes the mechanical friction from having moving or sliding parts.

Mike W.

(published on 10/22/2007)

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