Magnetic Levitation Trains

If you've been to an airport lately, you've probably noticed that air travel is becoming more and more congested. Despite frequent delays, airplanes still provide the fastest way to travel hundreds or thousands of miles. Passenger air travel revolutionized the transportation industry in the last century, letting people traverse great distances in a matter of hours instead of days or weeks.

The only alternatives to airplanes -- feet, cars, buses, boats and conventional trains -- are just too slow for today's fast-paced society. However, there is a new form of transportation that could revolutionize transportation of the 21st century the way airplanes did in the 20th century.

A few countries are using powerful electromagnets to develop high-speed trains, called maglev trains. Maglev is short for magnetic levitation, which means that these trains will float over a guideway using the basic principles of magnets to replace the old steel wheel and track trains. In this article, you will learn how electromagnetic propulsion works, how three specific types of maglev trains work and where you can ride one of these trains.

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 combine to propel the train.


Above is an image of the guideway for the Yamanashi
maglev test line in Japan.
  1. Why do countries feel the need to produce maglev trains (or even have a train system at all).
  1. What does it take to produce an electromagnet?
  2. What makes the train move?
  1. Why do you think we don’t have maglev trains running long distances in the United States.

Magnetic Resonance Imaging (MRI)

Dr. Raymond Damadian, a physician and scientist, toiled for years trying to produce a machine that could noninvasively scan the body with the use of magnets. Along with some graduate students, he constructed a superconducting magnet and fashioned a coil of antenna wires. Since no one wanted to be the first one in this contraption, Damadian volunteered to be the first patient.

When he climbed in, however, nothing happened. Damadian was looking at years wasted on a failed invention, but one of his colleagues bravely suggested that he might be too big for the machine. A svelte graduate student volunteered to give it a try, and on July 3, 1977, the first MRI exam was performed on a human being. It took almost five hours to produce one image, and that original machine, named the "Indomitable," is now owned by the Smithsonian Institution.

In just a few decades, the use of magnetic resonance imaging (MRI) scanners has grown tremendously. Doctors may order MRI scans to help diagnose multiple sclerosis, brain tumors, torn ligaments, tendonitis, cancer and strokes, to name just a few. An MRI scan is the best way to see inside the human body without cutting it open.

That may be little comfort to you when you're getting ready for an MRI exam. You're stripped of your jewelry and credit cards and asked detailed questions about all the metallic instruments you might have inside of you. You're put on a tiny slab and pushed into a hole that hardly seems large enough for a person. You're subjected to loud noises, and you have to lie perfectly still, or they're going to do this to you all over again. And with each minute, you can't help but wonder what's happening to your body while it's in this machine. Could it really be that this ordeal is truly better than another imaging technique, such as an X-ray or a CAT scan? What has Raymond Damadian wrought?

  1. Why do you think people would not have wanted to be the first to try out an MRI machine?
  1. Why do you think people must remove all jewelry before entering an MRI machine?
  1. What does the term “noninvasive” mean?
  1. Why do you have to remove all credit cards from your body?