Magnetic Levitation Trains – How Super Fast Trains Work

At top speed, a maglev train or magnetic levitation trains travels a few inches above the track and can cut commute times to as little as seven minutes. But how does this system of levitation allow it to reach such remarkable speeds?

The basic principle is similar to a regular electric rotary motor. However, there are a few key differences that can make all the difference.

Superconducting Magnets on Magnetic Levitation Trains

Magnetic levitation (MAGLEV) allows trains to travel up to 250 miles per hour. This is much faster than a conventional train running on wheels, which can struggle with the friction between track and wheel at high speeds.

Superconducting magnets suspend the train car above a U-shaped concrete guideway, and they use electromagnetic force to keep it there. The magnets have matching poles that repel each other, and the power to levitate the train comes from constantly alternating electric currents in the coils in the guideway walls.

The third set of loops is a propulsion system run on alternating current power. It uses both magnetic attraction and repulsion to propel the train car down the guideway. These vertical coils are called propelling coils, and they use magnets with north poles facing out in the front corners and south poles facing out in the back corners. When the coils are electrified, the magnetic fields pull and push the train forward from the front and behind respectively.

Electromagnetic Suspension on Magnetic Levitation Trains

This type of maglev train uses an array of insulated copper coils running along the walls of a track, called a guideway. The alternating current that runs through these coils creates a continuously varying magnetic field that pushes and pulls the train along the track.

The magnets on the train and the coils in the guideway are arranged in what is known as a Halbach array. They are made from a newer neodymium-iron-boron alloy that generates more powerful magnets. The power needed to achieve levitation on magnetic levitation trains is small, and the magnetic fields are a safe distance away from any passenger compartments that may contain pacemakers or passengers with magnetic storage devices like credit cards or hard disks.

The resulting system is extremely stable and doesn’t lose much energy to friction, which makes it possible to reach ground transportation speeds of up to 310 mph (500 kph). This would allow trains to connect cities that are 1,000 miles apart or more, cutting travel times to just 60 minutes or less.

Electrodynamic Suspension on Magnetic Levitation Trains

Magnets on the track and train exert opposing magnetic fields to repel each other, lifting the railcar about a half-inch above the track. That system is called electromagnetic suspension (EMS).

Maglev trains have a much more complex magnetic levitation system, known as electrodynamic suspension, or EDS. Its conductors are exposed to time-varying magnetic fields, causing eddy currents that create a repulsive force to keep the train and guideway apart (Lee, 2006).

This is what makes it possible for trains to be levitated at high speeds, as they’re not subject to friction or vibrations. But the EDS system also has its problems, like requiring more energy for powering the magnets and its inability to deal with a changing force of gravity over a range of speeds. Despite its challenges, maglev systems are more efficient than conventional trains, as they don’t lose energy to friction. They can carry more people and cover longer distances in a shorter period of time.

Inductrack

The Inductrack system is a newer type of electrodynamic suspension that doesn’t rely on super-cooled superconducting magnets or massive power-consuming electromagnets to produce magnetic fields. It uses permanent room-temperature magnets that are arranged in a special ladder-like array called Halbach arrays and interact with a close-packed set of track circuits to levitate the train.

The alternating currents passing over these coils change the polarity of the magnetized fields constantly, which produces a continuous flow of magnetic forces that keep the train centered and repelled from the ground. Computers are used to control these alternating currents to change their direction so the electromagnets in front of the train pull it and the ones behind add more forward thrust (Dona et al, 2017).

Inductrack II improves upon this technology by using dual Halbach arrays above and below the cantilevered track circuits to double the levitating force per unit area at a lower weight. Sensors monitor how high the train is above the guideway walls, and an onboard computer adjusts the electric current in the wire-coil electromagnets to keep the train at a constant height above the track.

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