Transrapid is one of the greatest prides of German engineering, being the first (and so far, the only) fully developed, working maglev high speed transport system in the world that has found government approval and commercial application. Transrapid is also one of the greatest sorrows of German governmental technology policy, as the massive funding poured into it has not led to any domestic application whatsoever. In 2003, the first (short) Transrapid line was finally built in China, but so far, no one knows whether there will ever be any large-scale Transrapid and if so, whether it will happen in Germany.
Transrapid: The system
It all seems pretty simple, but it's damn complicated when you look at it twice. Basically, it's a train held aloft by magnets, riding a linear motor that drives it forward. But that's not nearly all.
Support and guidance magnets
The TR looks like a shark swallowing a strip of concrete at improbable speeds. That's because the train's guidance/drive modules wrap around the guideway with the support magnets under it. Attracting the metallic armature inside the guideway, they keep the thing up. In the sides of the wraparound modules, guidance magnets act on side rails in the guideway. Computer-based, fast feedback logic tries to keep all distances constant at all times so no part of the TR will ever touch the guideway. The magnets are battery-powered; even on a powerless guideway, the train can stay afloat for about an hour.
Linear motor
The aforementioned armature in the guideway is the armature of a huge linear motor -- cables inducing current running through sections of packed sheet metal. By putting the right kind of AC into the armature at the right spot, the train's support magnets will act as the rotor of a synchronous electric motor and the thing will move. (This is why they call it long-armature technology, because the armature is as long as the line and the rotor is only as long as the train.)
Linear generator
Power transmission into the moving vehicle is done by onboard generator coils feeding off some kind of harmonic of the drive field. The Metrorapid, if it will ever happen, will however probably not feature the linear generator but something you would call a third rail if the thing had rails in the first place.
Guideway
The guideway is nearly more important than the vehicle itself, because it's here where the drive is installed and the magic happens. The concrete strip containing the armature has to be somewhat elevated above ground so the vehicle can wrap around it properly. At several points, electronic, remote-controlled power converters feed the proper variable-frequency AC to the armature.
The design almost requires that the guideway be elevated. This is passed as a selling point, as it is supposed to be less intrusive, lets animals and traffic pass underneath and makes the TR look like any good science-fiction-like monorail should.
Points
As you may have noticed, the guideway is complicated, massive and the train is utterly tied to it. It's kind of hard to realise points with the system, and it could be done only by tour de force: points consist of a segment of guideway implemented in elastic steel, which is bent out of shape by several servo motors to connect with the desired track. Transrapid points are large, complicated and friggin' expensive.
Control
Transrapid vehicles are passively moved back and forth on the track just like cable cars. There is no real need for a driver. All control is done centrally, via computer. (This was all very groundbreaking back in '79, remember.)
Transrapid lines (both of them)
TVE
The "Transrapid-Versuchsanlage Emsland" (Transrapid testing ground Emsland) in northern Germany is the largest-scale maglev testing installation anywhere. It consists of about 30 km of single-guideway track (elevated and non-elevated sections) in the shape of a straight line with loops at both ends. There is a station to the side of the track, which means a total of three points. If you have some spare cash, you can go there and actually ride the train. They do seem to do a good marketing job there as most people coming back from the TVE are madly in love with the Transrapid.
Shanghai-Pudong
This is a line much like the TVE. It connects Long Yang Road Station, Shanghai, with Pudong Airport and is about 30 km long. So far, it's just a representative toy as regular operation has not yet commenced. But apparently the Chinese make a lot of money selling Transrapid rides to tourists.
Transrapid: The vehicles
Unsurprisingly, all the vehicles operating in the Transrapid system are called Transrapid, too. Several models have been developed so far, all named "Transrapid xx", where xx is a class number (all so far padded with a leading zero):
Since Transrapid units are basically lightweight, motorless open-seating passenger cars without many moving parts, they aren't very exciting in the traditional, big-iron way locomotives are exciting. The technological meat is all in the on-board electronics.
Transrapid: The company
Transrapid International is a joint venture of Siemens and ThyssenKrupp. Seems like the name of Adtranz got lost somehow, perhaps because one of the countless wacky mergers in the rolling stock industry killed the company or they decided to bail out. Transrapid International was founded in 1998 to market the now-finished product. So far, there has been no real success; the Shanghai line is very much a toy like the TVE.
Transrapid: The discussion
This is perhaps the most-discussed topic of German traffic policy. Why was the Transrapid developed and why isn't it deployed? There must be a reason for this thing to exist other than desperation over problems with the classic steel-on-steel railway system, after all, it was developed at a time when Germany had somewhat credible high speed rail transport -- okay, the 103 and the ET 403 were not as spectacular as the TGV, but we had scheduled 200 km/h trains by 1971 and the prospects for increased speeds looked good.
Fact is: the TR is not a railway. It is something almost, but not quite entirely different -- something else. And, much to the chagrin of neophiliacs and much to the relief of trainspotters and ecologists, this "something else" may work out to be "a glorified airport shuttle". I cannot list all the pros and cons here, but I'll tell you right away that I don't think the TR stands much of a chance.
Pros (according to Transrapid International)
- Speed: The TR routinely operates at speeds which have been reached with steel-on-steel rail technology only in record attempts (between 400 km/h and 550 km/h are feasible). This makes the TR a direct competition to airlines rather than railways.
- Acceleration: Lightweight and riding a giant motor, the TR can achieve almost arbitrary acceleration, limited only by passenger convenience. It reaches 300 km/h within 5 km, while an ICE supposedly takes 30 km.
- Climbing ability: Again for the same reasons and because the motor segments can be built more powerful where necessary, the TR can negotiate very steep grades (up to 1-in-10).
- Safety: The TR is impossible to derail, and because all vehicles over the same section of armature always go at the same speed into the same direction, collisions are impossible, too.
Cons (according to less marketing-inspired people)
- Cost: Everything about the TR guideway is dramatically expensive because everything's an active drive element and in need of constant maintenance. Imagine a railway where each kilometre of track has to be maintained like a locomotive. And try to conceive the cost of a single set of computer-controlled, track-bending Transrapid points. (Putting everything on stakes doesn't make it cheaper, by the way.) In contrast, railway lines and points are dirt-cheap, especially with third-generation control systems like ETCS Level 3 where you can theoretically deal away with nearly all trackside installations because everything is remote-controlled and wireless.
- Inflexibility: The track is the motor and control is central. This means that in one section, only one train can move. This imposes several rigid limits on train operation. The high cost and large size of points also imposes a need to keep stations simple and rare, which will not make operation any easier; and while the TR can negotiate steeper grades than steel-on-steel high speed trains, it requires much larger curve radii.
- Incompatibility: TR isn't compatible with anything else. The conventional railway network will not profit at all from any TR line.
- Unresolved security issues: No one really knows how the TR will negotiate train encounters, snow, ice, trees on the track or sabotage. Damaged points could also cause a TR to catastrophically fly off the end of the bent guideway, though this would require a cascade of improbable failures.
- Energy consumption: While Transrapid International maintain the claim that the TR takes less energy per passenger to operate than a conventional train (which could be tied to the fact that TR seating is more cramped than, say, InterCity seating), other sources state it consumes more energy floating at a standstill than other trains consume moving and actually more than double the energy to move a square metre of car floor than the ICE.
- Competition by steel-on-steel railways The AVE will soon do 350 km/h on schedule -- on good, old Stephenson-style 1435 mm steel track. Rotary AC locomotive technology, modern bogies with pneumatic suspension and advanced track construction have enabled conventional high speed trains to achieve scheduled velocities undreamt of in 1970.
- Freight: Transrapid International have a design for a TR freight car. Yeah, right. At least they haven't got the audacity to claim anyone in their right mind would put 5,000-tonne loads of iron ore on magnets which eat expensive electric energy just keeping the stuff aloft; they say it would make sense to put time-sensitive container freight (think UPS or FedEx) on the TR. I don't believe them: it takes 3 tonnes of TR to transport 1 tonne of freight; for regular freight trains, the ratio is 2.5 tonnes of freight in 1 tonne of train!
The usual conclusion is that the TR is theoretically better than the aeroplane at long-range high-speed passenger transport, but would, to achieve this, require an absolutely mind-blowing starting investment. Easier to put some money into steel rails and the vehicles rolling on them, which has the nice side effect of improving the network for all kinds of rail traffic including real freight. Experts also agree that 500 km/h do not really make sense in ground-based transport, and the maximum sensible speed of around 400 km/h is not only achievable by steel-on-steel trains, but also not all that much of a revolution over the 300 km/h, 350 km/h or 380 km/h trains of nowadays.
Now that the Hamburg-Berlin TR will not happen, all kinds of alternative connections have been proposed. The Shanghai one has been built. Most of them are short point-to-point connections (yes, airport shuttles, you got it), but some proposals would like to make the TR a glorified S-Bahn.
Line proposals
Hamburg-Berlin
This one was nearly realised. Construction would have begun by now. The would-be operator, Deutsche Bahn killed the project telling everyone the truth about how economically unrealistic the line would be, and the German government did its part by not pouring any more fund into the project. It died around 2000. At the moment, the sensible alternative is being implement: at a fraction of the cost, the line is being upgraded for a top speed of 230 km/h.
Munich airport shuttle
This has always been a problem of the new Munich airport: there's no ICE access. In my opinion, this does not make a TR airport shuttle (from Munich Central Station to the airport) look very sensible, considering the airport already has an S-Bahn station. Why not give them some real track and a real ICE station? Come on, guys. It worked for Rhein/Main.
Metrorapid
This really has boondoggle potential: The proposal to put the funds dedicated to improving the Rhine/Ruhr rail infrastructure into a Dortmund-Düsseldorf TR line. This makes exactly zero sense as the rapid transit system there is massively networked in the usual vein of rapid transit systems, and the TR line would just absorb funds and by no means improve the network situation. Whether the TR would make a good commuter train at all is another question. It certainly wouldn't go much faster than a 420, as S-Bahn EMUs already accelerate as fast as is comfortable for the passengers.
Groningen-Randstad
A midrange project in the Nederlands. This has two parts: a ring line connecting the towns forming the Nederland's densely-populated urban core (the Randstad) and an Amsterdam-Groningen line connecting that ring to the North of the country. This looks like it might actually make some sense, as it's neither point-to-point nor a silly commuter train replacement proposal. Still undecided.
U.S. projects
A west coast system would connect Sacramento, San Francisco, Los Angeles, and San Diego (perhaps even Las Vegas); an east coast system would operate in the classic Boston-Washington corridor plus Pittsburgh. There are also some point-to-point projects, including the token airport shuttle (Pittsburgh). The TR might make more sense in the US than in Europe as the North American rail system is fucked up beyond belief optimised for slow bulk freight and high-speed traffic thus almost impossible. (Almost. See Acela.)