What is magnetic levitation technology?

Magnetic levitation (maglev) is a relatively new transportation technology in which noncontacting vehicles travel safely at speeds of 250 to 300 miles-per-hour or higher while suspended, guided, and propelled above a guideway by magnetic fields. The guideway is the physical structure along which maglev vehicles are levitated. Various guideway configurations, e.g., T-shaped, U-shaped, Y-shaped, and box-beam, made of steel, concrete, or aluminum, have been proposed.

Figure 1 depicts the three primary functions basic to maglev technology: (1) levitation or suspension; (2) propulsion; and (3) guidance. In most current designs, magnetic forces are used to perform all three functions, although a nonmagnetic source of propulsion could be used. No consensus exists on an optimum design to perform each of the primary functions.

Suspension Systems

The two principal means of levitation are illustrated in Figures 2 and 3. Electromagnetic suspension (EMS) is an attractive force levitation system whereby electromagnets on the vehicle interact with and are attracted to ferromagnetic rails on the guideway. EMS was made practical by advances in electronic control systems that maintain the air gap between vehicle and guideway, thus preventing contact.

Variations in payload weight, dynamic loads, and guideway irregularities are compensated for by changing the magnetic field in response to vehicle/guideway air gap measurements.

Electrodynamic suspension (EDS) employs magnets on the moving vehicle to induce currents in the guideway. Resulting repulsive force produces inherently stable vehicle support and guidance because the magnetic repulsion increases as the vehicle/guideway gap decreases. However, the vehicle must be equipped with wheels or other forms of support for "takeoff" and "landing" because the EDS will not levitate at speeds below approximately 25 mph. EDS has progressed with advances in cryogenics and superconducting magnet technology.

Figure 2 and Figure 3 Propulsion Systems

"Long-stator" propulsion using an electrically powered linear motor winding in the guideway appears to be the favored option for high-speed maglev systems. It is also the most expensive because of higher guideway construction costs.

"Short-stator" propulsion uses a linear induction motor (LIM) winding onboard and a passive guideway. While short-stator propulsion reduces guideway costs, the LIM is heavy and reduces vehicle payload capacity, resulting in higher operating costs and lower revenue potential compared to the long-stator propulsion. A third alternative is a nonmagnetic energy source (gas turbine or turboprop) but this, too, results in a heavy vehicle and reduced operating efficiency.

Guidance Systems

Guidance or steering refers to the sideward forces that are required to make the vehicle follow the guideway. The necessary forces are supplied in an exactly analogous fashion to the suspension forces, either attractive or repulsive. The same magnets on board the vehicle, which supply lift, can be used concurrently for guidance or separate guidance magnets can be used.

Maglev and U.S. Transportation

Maglev systems could offer an attractive transportation alternative for many time sensitive trips of 100 to 600 miles in length, thereby reducing air and highway congestion, air pollution, and energy use, and releasing slots for more efficient long-haul service at crowded airports. The potential value of maglev technology was recognized in the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA).

Before the passage of the ISTEA, Congress had appropriated $26.2 million to identify maglev system concepts for use in the United States and to assess the technical and economic feasibility of these systems. Studies were also directed toward determining the role of maglev in improving intercity transportation in the United States. Subsequently, an additional $9.8 million were appropriated to complete the NMI Studies.

Why Maglev?

What are the attributes of maglev that commend its consideration by transportation planners?

Faster trips - high peak speed and high acceleration/braking enable average speeds three to four times the national highway speed limit of 65 mph (30 m/s) and lower door-to-door trip time than high-speed rail or air (for trips under about 300 miles or 500 km). Still higher speeds are feasible. Maglev takes up where high-speed rail leaves off, permitting speeds of 250 to 300 mph (112 to 134 m/s) and higher.

Maglev has high reliability and less susceptible to congestion and weather conditions than air or highway travel. Variance from schedule can average less than one minute based on foreign high-speed rail experience. This means intra and intermodal connecting times can be reduced to a few minutes (rather than the half-hour or more required with airlines and Amtrak at present) and that appointments can safely be scheduled without having to consider delays.

Maglev gives petroleum independence - with respect to air and auto because of Maglev being electrically powered. Petroleum is unnecessary for the production of electricity. In 1990, less than 5 percent of the Nation's electricity was derived from petroleum whereas the petroleum used by both the air and automobile modes comes primarily from foreign sources.

Maglev is less polluting - with respect to air and auto, again because of being electrically powered. Emissions can be controlled more effectively at the source of electric power generation than at the many points of consumption, such as with air and automobile usage.

Maglev has a higher capacity than air travel with at least 12,000 passengers per hour in each direction. There is the potential for even higher capacities at 3 to 4 minute headways. Maglev provides sufficient capacity to accommodate traffic growth well into the twenty-first century and to provide an alternative to air and auto in the event of an oil availability crisis.

Maglev has high safety - both perceived and actual, based on foreign experience.

Maglev has convenience - due to high frequency of service and the ability to serve central business districts, airports, and other major metropolitan area nodes.

Maglev has improved comfort - with respect to air due to greater roominess, which allows separate dining and conference areas with freedom to move around. The absence of air turbulence ensures a consistently smooth ride.

The National Maglev Initiative (NMI)

Since the termination of Federal support in 1975, there was little research into high-speed maglev technology in the United States until 1990 when the National Maglev Initiative (NMI) was established. The NMI is a cooperative effort of the FRA of the DOT, the USACE, and the DOE, with support from other agencies. The purpose of the NMI was to evaluate the potential for maglev to improve intercity transportation and to develop the information necessary for the Administration and the Congress to determine the appropriate role for the Federal Government in advancing this technology.

In fact, from its inception, the U.S. Government has aided and promoted innovative transportation for economic, political, and social development reasons. There are numerous examples. In the nineteenth century, the Federal Government encouraged railroad development to establish transcontinental links through such actions as the massive land grant to the Illinois Central-Mobile Ohio Railroads in 1850. Beginning in the 1920s, the Federal Government provided commercial stimulus to the new technology of aviation through contracts for airmail routes and funds that paid for emergency landing fields, route lighting, weather reporting, and communications. Later in the twentieth century, Federal funds were used to construct the Interstate Highway System and assist States and municipalities in the construction and operation of airports. In 1971, the Federal Government formed Amtrak to ensure rail passenger service for the United States.

Magnetic levitation is the use of the repulsion and attraction force of magnets to levitate things. The most commonly known use of the technology is the magnetic levitated (maglev) trains. Maglev trains can attain high speeds because they travel without friction and unlike trains with wheels, don't have to be aligned with a track. They operate over a guide way. In one design, known as electrodynamic suspension, super conducting magnets on the train and electrically-conductive strips or coils in the guide way set up a magnetic field that lifts the train above the guide way and keeps it stable. Maglev trains can sustain speeds 500 km/h (300 mph).

Make a Magnetic Levitating Train

Introduction: In magnets like poles repel. In other words N poles repel N poles and S poles repel S poles. The abilities of magnets to repel each other has provided the idea of making levitating trains. Levitating trains do not make a loud noise as regular trains do. They can also travel faster due to lower friction between the train and the rails.
Magnetic trains do not need wheels. They just need a magnetic rail on the ground and a like magnetic rail on the train cars.

Materials
To construct a model of magnetic levitating train you will need the following materials.

Included in your kit:

2 long hi-force Magnetic Strips (for the rails)
2 short hi-force Magnetic Strips (for the car)
2 plastic Guide Rails
Wood Block 5" x 1 1/2" x 3/4" for the car

Additional materials you need:

Wood board or heavy cardboard 3" x 28" or larger. This will be the ground for your train.
Clear adhesive tape
Foam board or construction paper for making a decorative train
Wood glue or Elmer glue to connect the foam parts (optional)
A ruler stick
Pencil
This instruction page

Procedure Quick Reference:

Peal the plastic film from the back of 5" long magnet strips and connect them on one side of the 5" x 1 1/2" wood block. This will be the train car. As you see in the picture in the right, the strips are aligned to the edges of the wood block and are 1/2" apart.
Peal the plastic film from the back of 24" long magnetic strips and mount them parallel to each other, exactly 1/2" apart, on a long wooden board or rigid card board.
Mount the clear plastic angles on the sides of the long magnetic strips to form a protective wall so the levitating car will not move off rail. There must be a very small gap between the car and the walls so the car can move freely.

In this method the angle brackets are installed towards outside. In other words the horizontal surface of the brackets are away from the rails. This methods allows you to adjust the position of side rails later. The angle brackets can be secured using masking tape, clear adhesive tape, or small screws.Another method described in the detail procedure below is suggesting the brackets to be mounted towards inside. You choose which method you want to use.

Procedure Details:

Draw 2 parallel lines 24" long and 1/4" apart as the guideline for mounting plastic rails (angle brackets). Number these lines as line 1 and line 2.
draw 2 more parallel lines 1/8" outside the first two lines. These 2 new lines will be used as the guideline for the magnet strips. We name these new lines , line A and line B.
Place one of the angle brackets on the board and align its edge to the line number 1. At this time the flat section of the angle bracket will cover the line A and the wall section of that will stay on the left of line A. Use tape to secure it at this position.
Place the other plastic angle bracket on the board and align its edge to the line number 2. At this time the flat section of the angle bracket will cover the line B and the wall section of that will stay on the right of line B. Use tape to secure it at that position.

Place your train car between the rails and make sure that it can move freely and the space between the walls and train is as small as possible.

Peal the plastic film from the back of 24" long magnetic strips and mount them on the flat section of angle brackets. One must be aligned to line A and the other must be aligned to line B. In this way two magnetic strips will be exactly 1/2" apart.

Place the rail board on a flat horizontal surface and then place the train car over the rail. It must float and the side brackets must protect it so it does not go off road.

Further adjustments and alignments:
If the magnets are very strong you may need to make your train heavier by adding weights or loads. You may also use the super strong neodymium magnet to modify the strength of your plastic magnet strips. Please be cautious in doing this because imbalance in the strength of magnet strips can potentially disable your train.

To increase the strength of plastic magnet, place the neodymium magnet on the magnet strip so that it will be attracted, then rub the magnet all over the surface of both rails on the ground.To reduce the strength of magnet, hover the neodymium magnet above the magnet strip so that it will be repelled by the plastic magnet, then move it along the rail.

To be more precise in this procedure, you must first identify the N and S of your plastic magnets and your neodymium magnet. You may use a compass to identify the poles. The south pole of the compass needle is the one that shows the north and attracts to the N pole of magnets. Also the North pole of a compass needle stays towards the south pole and attracts toward the S pole of magnets.
To increase the strength of plastic magnet, rub its surface with the opposite pole of the neodymium magnet. To reduce its strength, hover the like pole of the neodymium magnet above its surface.
Note: Super strong Neodymium magnet is also able to reverse the poles of a plastic magnet. For example if the surface of plastic magnet is N, you can rub that surface with the N pole of neo magnet in order to change it to S.

Decoration:Make a decorative train using Styrofoam or construction paper and mount it over your wooden train base. A decorative structure makes your train more attractive for your science project display.
You can glue or tape any decorative train car above your wooden train.

If you cut the foam to exact size of your wooden train, you will not need to use tape or glue. The model can sit right on the top of the wooden train and hold it snugly.

Additional upgrades:

The wooden train or the decorative train above that may be equipped with ejecting magnets so they can smoothly eject at the end of the rail. Ejecting magnets are usually rectangle magnets or small disk magnets that may be screwed or taped to both ends of a train.
To make these work, matching magnets must be mounted at the end of each rail in a way that they repel the train magnets.

The magnets at the end of the rail must be fully aligned with the train magnets so they can repel the train when it gets to the end of line.End of line magnets may be mounted on another wood block or a small cardboard or plastic box.
Picture in the right shows an end of line magnet mounted on a wooden block that is hold in place using rubber bands.