The longest, largest, and fastest maglev train in the world, situated at the Yamanashi test track in Japan, has restarted public testing. The test track has recently been extended to 42.8 kilometers (26.5 miles), allowing for a five-car prototype train to be routinely pulled at speeds of over 500 kph (310 mph). The train accelerates to max speed in under three miles, and according to the Japanese journalists the ride is very smooth. On the inside, anyway: Externally, according to one journalist, the L0 Series train created "a shock wave and a massive gust of wind ... a deafening sound that made conversation all but impossible" as it passed by (video below).
Maglev, as you probably know, stands for magnetic levitation. There are many varieties of maglev, but in Japan's case the L0 Series trains have superconducting magnets on the carriage and wire coils along the track. To begin with, the train rolls along on rubber wheels, but once it reaches 150 kph (93 mph), the magnetic field induction effect created by the superconducting magnets passing by the coils creates enough current to levitate the train 10cm (4 in) off the track. Because the coils on each side of the track are connected, the induced current automatically stabilizes the train if it moves off-center. A second set of coils provides linear motor propulsion (a lot like a railgun).
The main advantage of maglev is that, except when starting off, it doesn't use wheels. Wheels introduce a whole raft of engineering concerns that are difficult and costly to overcome, such as massive wear and tear, breaking distances, and frictional losses. Levitation, due to the complete lack of friction, is quieter and smoother for passengers. The lack of wheels also means that the system requires much less maintenance, and can also operate under almost any weather condition. Despite these advantages, though, it still isn't clear if maglev is commercially viable: While the running costs are significantly lower than wheel-rail systems, the initial installation cost is massively expensive. The Chuo Shinkansen Tokyo-Osaka maglev line, which is scheduled for completion in 2027(Opens in a new window), is currently estimated to cost nine trillion yen, or around $91 billion.
Maglev is one of those technologies that's awesome on paper, but verges on complete impracticality when transported to the real world. It might be fast, and it might revolutionize mid-range national transport, but the fact that it costs a fortune and is completely non-backwards-compatible with existing rail networks means it will take a very, very long time for maglev trains to appear in the real world -- if they ever appear at all.
At this point, we obviously have to mention Elon Musk's Hyperloop, too, which promises to be a cheaper and faster version of maglev. Maglev has the distinct advantage that it's been in development for decades and is basically ready for commercial use, while Hyperloop is barely more than some back-of-the-napkin sketches -- but it's hard to ignore a system that promises to be twice as fast, while requiring just a fraction of the initial outlay.
Now read: Who needs Hyperloop? Consumer jetpack to release by 2015
