What's the idea? Just imagine a futuristic train. It's slim, sleek, quiet, and super-fast. Well after you stop imaging, take a nice look at the picture below and see if it fits what you thought up. The future is here. This is a picture of a special magnetically levitating train, called a maglev.

A maglev train soars along a guideway and cuts through a wooded area. Photograph courtesy of Transrapid International-USA, Inc.

When could it happen? Prototypes of the maglev technology have existed for years, but only recently have they been coming into wider use. This train is still in testing in Japan, but in the future it will probably be used all over the world. Newer and better versions of the original maglev prototypes are being produced. The Inductrack is still in its development phase.

How does it work? Reaching speeds up up to 310 miles per hour (approximately 500 km/h), the maglev works on magnets. The term maglev is short for "magnetic levitation."

The "magnet" in magnetic levitation refers to the electromagnetic magnets on the guideway, or train. The guideway is the steel "track" running under the train. The "levitation" refers to the train hovering above the guideway.

There are three main ways to levitate the train. Two of the three technologies used for maglevs involve electromagnets. Electromagnets come from the magnetic field produced by an electric current. In electrodynamic levitation, the magnetized coil running along the guideway repels the large magnets on the train's bottom. This allows the train to float 0.39 to 3.93 inches (1 to 10 cm) above the guideway.

In the second method, called electromagnetic levitation, the bottom of the train wraps down around an extended part of the guideway. Electromagnets on the bottom of the train face upwards towards the guideway. The propulsion (attraction) of the magnets is strong enough to actually push the train up into the air. Although it is still using wheels, the train is pushed upwards, which decreases the friction and makes it move faster. Once the train is hovering, power is supplied to the magnetized wire within the guideway walls to create a special system of magnetic fields that pull and push the train along the guideway. The electric current in the coils in the guideway walls is constantly changing which changes the poles of the coils. This change in poles makes the magnetic field in front of the train yank the vehicle into motion.

The bottom of the maglev train literally wraps around the guidway. Photograph courtesy of Transrapid International-USA.

The third method, a promising technology called Inductrack, is very straightforward. The track, which could potentially be created through updates on current rails, is wrapped with unpowered, passive wire coils. The train, whose underside is fitted with arrays of permanent magnets, first needs to reach a certain starting speed before levitation begins. The train is accelerated on wheels by a conventional motor. At around 20 miles per hour (32 km/h), the permanent magnets on the train and the inductive coils on the track repel. The permanent magnets are in a special setup called a Halbach array, which allows the magnetic field to be focused on alternating sides. The changing magnetic field produces an electric charge in the coils.

Using the powerful Inductrack system, a permanent magnet could levitate fifty times its own weight.

Why do people need it? Diesel trains rapidly consume fossil fuels. While the maglev provides a fast, hi-tech alternative, it also uses tremendous amounts of power. Hopefully technologies like Inductrack, improvements upon the earlier maglev, will provide no-fossil fuel, low-power substitutes for both technologies.

A note on the standard train

The standard train, unlike the maglev, has a diesel engine similar to the one in a car. However, as opposed to the four stroke internal-combustion engine used in cars, the standard locomotive uses a two-stroke engine. This engine pulls the train forward. Unfortunately, the diesel engine of the standard train requires a large amount of precious fossil fuel. That is why the fast, quiet, efficient maglev is a good alternative.

Sources Used

Bonsor, K. (n.d.). How maglev trains work. Retrieved February 15, 2005, from http://travel.howstuffworks.com/maglev-train.htm

Gourley, S. R. (n.d.). Track to the future: Maglev trains on permanent magnets. Retrieved February 15, 2005, from Popular Mechanics Magazine Web site: http://www.popularmechanics.com/science/transportation /1289196.html?page=1&c=y

Mavlev: Photos. (n.d.). Retrieved March 11, 2005, from Transrapid International-USA Web site: http://www.maglev-train.com/press_room/photos.asp

Nice, K. (n.d.). How diesel locomotives work. Retrieved February 15, 2005, from http://travel.howstuffworks.com/diesel-locomotive.htm

Transrapid International-USA, Inc. (Ed.). (2003, November/December). Transrapid U.S. reporter. Retrieved March 11, 2005, from http://www.transrapid-usa.com/pdf/ NovDec03%20TRI-USA%20Newsletter.pdf

Transrapid International-USA, Inc. (Ed.). (2004, January/February). Transrapid U.S. reporter. Retrieved March 11, 2005, from http://www.transrapid-usa.com/pdf/ JanFeb04%20TRI-USA%20Newsletter.pdf

Transrapid International-USA, Inc. (Ed.). (2005, Winter). Transrapid U.S. reporter. Retrieved March, 2005, from http://www.transrapid-usa.com/pdf/Winter04-05%20TRI-USA%20Newsletter.pdf

What is maglev? (n.d.). Retrieved March 11, 2005, from Transrapid International-USA Web site: http://Mavlev: Photos. (n.d.). Retrieved March 11, 2005, from Transrapid International-USA Web site: http://www.maglev-train.com/press_room/photos.asp

from : http://library.thinkquest.org/04oct/01249/