How the maglev train works

The maglev train that can run at high speeds by ‘floating’ above the track is an engineering marvel that people in the US unfortunately have no direct experience with, thanks to the gas and automobile lobbies effectively killing the train system so that what exists here is an embarrassment when compared to what exists in other parts of the world. Eric Laithwaite, known as the father of the maglev train for his development of the magnetic levitation process, takes us step-by-step through the design of the system.

Maglev (magnetic levitation) trains are elegant and audacious works of engineering that operate by harnessing the power of magnetic repulsion and electromagnetism to move traincars that quite literally float above the track – today, often at speeds of hundreds of miles per hour. In this lecture at Imperial College London from 1975, the British engineer and professor Eric Laithwaite (1921-97) deconstructs the fascinating physics at work behind his plans for a maglev train, which he first modelled in 1940s and perfected in the 1970s. Well-regarded in his time as both a lecturer and an engineer, Laithwaite presents a series of demonstrations that build, step by step, until he finally unveils a small maglev train model. The first commercial maglev train debuted at Birmingham Airport in 1984, and today Laithwaite’s engineering breakthroughs help power many of the world’s fastest trains.


  1. billseymour says

    Maglev technology is very expensive; and if we ever get such services, they’ll likely be point-to-point like airline flights to maintain short travel times. Even for conventional passenger trains, much time is spent, not just for station stops themselves, but for deceleration from, and acceleration to, track speed. Deceleration and acceleration times would probably increase about linearly with top speed to avoid throwing the passengers around.

    A much better plan, IMO, is to reduce travel times for conventional passenger trains; and we’d get the biggest bang for the buck by improving the slowest sections of existing track, not by increasing top speed.

  2. sonofrojblake says

    I met Laithwaite in 1986. He was a charming and charismatic lecturer. He was also something of a crank, convinced he was this close to working out how to use gyroscopes to levitate.

    I recall clearly one of the elements of his lecture was his claim that, at root, ALL human technology had roots or equivalents in nature -- that some organism somewhere on earth had got there first. He produced a number of impressive examples. At the end of the lecture, during the Q&A, I asked which organism was able to generate a beam of coherent light -- could anythin in nature make a laser? His answer was that bats could produced acoustic holograms to confuse their prey. Great answer. I’d be really interested to see if anyone can find any corroboration for it, because I’ve been unable to.

    This seems disingenuous:

    The first commercial maglev train debuted at Birmingham Airport in 1984, and today Laithwaite’s engineering breakthroughs help power many of the world’s fastest trains

    I’d be interested to know when “Today” is in that quote, because if it’s any later than 1995 it’s being economical with the truth not to mention that Laithwaite’s maglev at Birmingham (all 600 metres of it -- not a misprint, less than 0.4 miles), closed after less than eleven years of operation and was replaced by a more mundane cable-haulted system. Maglev is an engineering curiosity and a technological dead-end. In that, it’s a lot like that other great British invention of a similar time, the hovercraft, although there are still some functional examples of those still in operation, just not crossing the Channel like they did when I went interrailing as a teenager. The future’s not what it used to be…

  3. robert79 says

    The problem I have with a “lecture” like this is, at the end of it you actually haven’t learned anything applicable. You’ve learned that you can make a magnetic train using magnets, but no one can actually reproduce his magnetic train from this video. The laws of magnetism have been known since the 1800s (Maxwell and Faraday and such) but I can’t deduce what the driving forces are from his explanation combined with my knowledge of magnetism (and I studied physics as an undergrad.)

    So is this really a great lecture? Did we really learn anything?

    Also… damn that thing is noisy… is it really energy efficient, let alone pleasant to use, if it’s making all that noise? What is *causing* all that noise?

  4. seachange says

    California High Speed Rail Authority has said that our version of the shinkansen will be steel-on-steel.

    The original rights of way and the original rails of California were along the coast, likely because steam-power required easily sourced water and the California Aqueduct was not in existence then. However, it looks like the HSR will skip you in Monterey, it heads inland from San Jose. Fresno (Fresno?) gets a spur, but Sacramento doesn’t.

    It also appears that Ms Yee is not doing her job, California’s bond rating is at risk, or she is taking it a little to literally? Because the legislature needed to add some lubrication-money in to make sure that it stays in-construction.

  5. mailliw says

    @6 jkrideau

    There is that short distance one around Shanghai that’s been running for years (airport to somewhere maybe?).

    The Shangai maglev is technology developed in Germany -- the Transrapid.

    Maglev has been abandoned in Germany despite Thyssen Krupp and Siemens being world leaders. Japan and China are as far as I am aware the only two countries still developing maglev.

    The problem with maglev is that it needs a whole new infrastructure. High speed conventional trains can only achieve their top speeds on specially prepared tracks with no other traffic, but they can also run on standard stretches of track too.

    But keep an eye on the engineering company Max Bögl who are developing their own maglev system from deep in the German provinces of the Oberpfalz (though I am not sure if this actually some kind of April fool’s joke)

    If it is true then I would wholeheartedly welcome the revival of the splendidly named Bayerische Magnetschwebebahnvorbereitungsgesellschaft (Bavarian Society for Preparing for Magnetic Levitation Railways).

  6. Reginald Selkirk says

    @4 robert79: So is this really a great lecture? Did we really learn anything?
    … What is *causing* all that noise?

    The lecture was very engaging. It seems to me the sort of presentation that might inspire people to go learn the details elsewhere. For example, the different metals shown: iron, aluminum, copper, behave differently in magnetic fields. A person might want to go find a textbook or encyclopedia and investigate that. (From high school physics I remember the terms “ferromagnetic” vs. diamagnetic” but don’t especially remember what causes the difference.)
    The noise is “electrical hum.” It is either 50 or 60 Hz, depending on locale. The power you get from a socket, which is fed by the grid, is AC (alternating current) and the voltage cycles positive and negative at a frequency of 50 or 60 Hz. This causes things to vibrate; specifically things like the wires in the electromagnet coils, which are made of copper. Electrical hum can be reduced by minimizing the vibration of parts, for example by coating coils in epoxy. And yes, it takes energy to create that noise, so it is fair to consider it an inefficiency.

  7. jrkrideau says

    @ 7 mailliw
    Ah yes, i had forgotten it was German.
    The problem with maglev is that it needs a whole new infrastructure.

    True but that does not mean China might not be willing to build a few thousand kilometres of track. Much of Eastern China has the density to justify it. It might be justifiable as a carbon-reduction move. With the speed quoted in that clip it could take quite a few planes out of the air the way the early TGV did on the Paris-Lyon run.

  8. Reginald Selkirk says

    If you extrapolate the technology in a different direction, you could come up with a “rail gun” which could take more planes out of the air!

Leave a Reply

Your email address will not be published. Required fields are marked *