Horse Stability Enhancement asks
Superconductors are cool. And we already have Maglev trains. Why aren’t they going everywhere – is it just price or is there physics in the way?
Why aren’t we making maglev cars?
Where are all my superconductors?
This is more to do with economics and the costs of deploying a new technology than it is actually developing that technology in the first place. As you say, we already have maglev trains and have done for several decades. Most commercial examples ceased operations in the 90s and the remaining functioning maglevs are mostly to be found in Asia. If the technology has been around for that long then why aren’t we looking at a country covered in a criss-cross of maglev lines if they’re so much better than trains? To answer this we need to look at two or three factors: the way new technology is introduced to society in general, the specific problems facing widespread deployment of maglev technology, and the revolutions in transport that have taken place in the past – specifically from canal boat to train, and from horse to car.
Steam engine tech had been around for some time before Robert Stephenson built the Locomotion in 1825. Railways had also been around for a while, mostly revolving around using horses to pull carts containing passengers and/or cargo along a set of fixed tracks. This was also the method used to make canal boats go, and canal boats were the primary means of cargo haulage around the interior of Britain before the railways. The dawn of the train as we understand it today came when steam engine technology had advanced to the point where it was suitable to be integrated into locomotives, combining the two concepts of steam engine and railway. The first steam-powered locomotive was built in 1811; the Stockton and Darlington railway was opened in 1825; and by 1850 Britain had 7000 miles of railway track (thanks, Wikipedia). That’s about three to four decades between the first practical application of steam engine technology to transport and its widespread deployment.
You’re looking at an even greater amount of time separating the invention of the automobile and it becoming the ubiquitous transport mechanism of the 20th century; remember, while the mechanized blitzkrieg tactics of the Wehrmacht function as the poster child for World War 2, and while the Germans had built their autobahn system as a way of recovering from the Great Depression and the hyperinflation of the Weimar Republic, even when the Germans were at the peak of their military power a large portion of the German army still used horses (or marching on foot) as their primary means of transportation. It takes a long time for a genuinely new technology to achieve maturity and achieve a foothold in the public sphere; even in the usually fast-moving electronics and communications industries mobile phones, computers, and even the internet all took 10-20 years before they were inextricably integrated into the fabric of Western society.
What I’m saying here is that it’s not like somebody invents maglev technology and the very next day there’s a whole bunch of investors clamouring for the opportunities to build maglev lines everywhere. It takes a long time for the technology to advance to the point where it is cost-effective in comparison to other forms of transport – such as our bog-standard trains – and that’s something that won’t even happen at all if people don’t bother to develop the concept and find affordable ways of deploying the tech. This is exacerbated by some complications inherent in the way maglev trains work.
Making a maglev system isn’t quite as simple as getting a magnet of one polarity, sticking it on top of a magnet of the opposite polarity, and watching it float. If you try that in real life what will actually happen is that the “floating” magnet will shoot off to the side; this is down to something called Earnshaw’s theorem which basically states you can’t have two static magnetic fields balanced against each other in perfect equilibrium. The system will always be in a state of permanent imbalance one way or the other. Maglev technology gets around this limitation by using electromagnets to “adjust” the magnetic fields on the fly, keeping the system in a state of controlled imbalance and hopefully keeping your maglev train hurtling along the track instead of into an apartment building. Unfortunately this kind of means you have to build electromagnets into both your maglev train and your maglev track1, which makes building even a few dozen kilometres of maglev track ruinously expensive. How expensive? Well, a cost of about five hundred million quid for ten kilometres of track would be about the kind of ballpark we’re talking about.
In the face of that kind of investment it’s entirely unsurprising that risk-averse governments are particularly leery of spending money on something that they still regard as unproven technology when conventional trains are right there and can use already existing track that’s fully integrated into urban areas etc. And this is a shame, because if the prohibitive initial cost could be reduced maglevs have several significant advantages over conventional trains – they’re faster, they make less noise and the fact that they don’t actually touch the track they travel over means there’s less wear and tear due to friction, which is the main problem with maintaining a normal piece of rail track. As it stands the only countries making any kind of significant investment into maglevs are in Asia: China (huge population making efficient mass transit a necessity) and Japan (existing high-tech train system means far less political resistance to new transport technology), and even the tracks that have been built there have run into non-technological problems (like the Chinese track terminating 20 minutes from anywhere interesting because it couldn’t get any further into the destination city).
Unlike the railways and the automobile, then, maglevs are a technology that isn’t attracting the same kind of fevered capitalistic gold rush that previous transport revolutions have provoked; it’s complicated, expensive and very finicky to deal with, and the benefits are not currently seen to outweigh the immense construction costs. Give it time, though. The maglev will have its time in the sun, and that’s likely to come around when the US (and other large countries) realises it needs a quick and efficient means of mass transit that isn’t air travel. Until then I’m afraid you’ll just have to wait if you want to ride on a maglev train. Or go to Japan. Either’s good.
1. Well, not strictly true. There are two ways of doing maglevs: electromagnetic suspension and electrodynamic suspension. Electrodynamic works as described. Electromagnetic suspension is a bit more complicated; the track is made of steel and electromagnets on board the train are responsible for the levitating, the catch being that due to the previously mentioned instability the feedback systems have to be ridiculously good because the optimum distance between track and train in this case is about a centimetre and a half, which doesn’t allow much margin for error. Either way costs silly money right now.