2 main types of maglev systems


ElectroDynamic vs Electromagnetic

ElectroDynamic:
The electrodynamic suspension system relies on superconductor electromagnets to create powerful magnetic fields that levitate the train as much as 10cm off the track. As mentioned in levitation these trains require a velocity of about 100km/h (Or about 50mph) before the induced magnetic field is strong enough to lift the train. Once lifted though, the only slowing factor these trains experience is the drag from the passing air. These creates an incredibly fast and smooth journey for the passengers. In fact the highest velocity recorded so far was 375mph achieved in Japan. One benefit of this system is that it doesn't require constant monitoring due to the flux pinning that occurs due to the superconductors. With EMS the magnetic fields are constantly changing and is inherently unstable and thus requires constant monitoring and a computer to make sure that it does not hit the guideway and damage the train or the track.
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The downside to this is the expensive refrigeration process. Superconductors require extraordinarily low temperatures to operate and if they do not maintain this critical temperature the system will fail to generate the appropriate magnetic field.
The extremely strong magnetic field that is produced by the superconductors also make shielding required as passengers with medical equipment like a pace maker or even a hard drive on them may have their devices disrupted.


ElectroMagnetic Suspension (EMS):
With electromagnetic suspension there is no refrigeration and the system relies on conventional electromagnets. With this structure the train actually wraps around the track and has magnets on the side of the track to keep the train centered. As long as current flows through the track this train will remain levitating regardless of it's velocity. This means that it does not require a "running start" as the EDS system requires making it more efficient in terms of friction avoidance. This system is only slowed by air as well and reaches extraordinarily high speeds as well. It also requires no shielding as the magnetic fields are not powerful enough to interfere with passenger's equipment or medical devices.

The downside to this system is that it requires constant monitoring. The magnetic fields are not pinned due to superconductors so it is constantly wavering through minute changes and the gap between the train and the track is about 10mm so there is a minute amount of wiggle room. To compensate for this a computer monitors this distance and adjusts the train so that no contact occurs.