I think your claims about maglev merit correction. You make two claims. First, that maglev hasn’t found widespread use because the vehicles “need a dedicated right of way and cannot operate on existing rail infrastructure”. And second, “MagLev trains contain onboard super-cooled magnets that are repelled by the application of an electric current built into the dedicated pathway”. I’ll address each in turn.

1. Much like electric or fuel cell cars, the main reason maglev is still not very widespread is that it is a still-developing set of related and often incompatible technologies, with all that implies for standards, infrastructure and so on. The fact that (current, first-generation) maglev technologies all require a dedicated right of way and cannot operate on existing rail infrastructure is not necessarily a point against them, though. The same incompatibility holds for rail w.r.t. roadways and vice versa, and when the twain meet, we know the kinds of problems that result. And, coming to mention it, similar observations hold for high speed rail (with all the extra stresses on the track and railbed) coexisting with existing lowspeed rail, especially freight rail. None of this has ever been mooted as an argument against rail (or highways, depending on which you prefer) — yet the logic holds as strongly (or weakly) in one case as in the other. Same for airplanes: you need special, land-hogging airports for them to take off and land: they are incompatible with existing roadways and rail lines. Not much of an argument against.

All that doesn’t go to say that a maglev technology that *is* designed to be compatible with existing rail infrastructure — and could integrate with air infrastructure to boot — would not have significant and obvious advantages over current maglev technologies. We are used to intermodal transportation nodes already. You walk, pedal, take a bus, metro or tram, or drive to a train station and reverse the process at the other direction. Same with intercity bus, same with airports (and to a far lesser extent than in the past), and boats (and with these last ones, trains often come into the picture). Intermodal transfer points are a crucial aspect of intercontinental freight transportation.

The fact is that the two American co-inventors of the superconducting maglev technology being built in Japan (one of them from Richmond, Ontario originally, only about five doors down the main street from where I used to live) have taken the first steps in developing and testing a new generation of maglev technology that is specifically designed to operate along existing rail where desirable, transferring seamlessly back and forth to and from their main mode, namely grade-separated raised monorail guideways. The narrow, low-cost monorails are designed for safe 500 km/h operation outside urban areas, but can also be used in cities in areas where existing rail can’t take the vehicles. Example: a cross-country raised guideway from Montreal transitioning to existing track in southeast Ottawa into Tremblay Road station, with a low-footprint, raised guideway spur into the old Union Station at Rideau and Nicholas — perhaps with a raised platform station in between what is now the government conference centre and the Rideau Centre.

I’ve been following their work for a decade and a half, and met them on Long Island last year after proofreading their first book on the subject, _The Fight for Maglev_. I am in the middle of proofreading their second book at the moment: believe me, I’m familiar with the details! (smile)

You *could* conceivably integrate the Japanese and German maglev technologies with railway infrastructure (and the Germans have actually published drawings of a way to do it), but it would be much more awkward and expensive to do so than the simple and elegant procedure of attaching individual guideway panels on either side of the rails in the second-generation design.

2. First, maglev is a different paradigm from rail. Vehicles need not be linked together in consists like trains, anymore than vehicles on a highway. In all cases, there is a certain efficiency in doing so to reduce overall air drag at high speeds and thereby save on power over long distances. It’s only really with rail that train-like consists have been an inherent necessity: it’s more efficient to use a single powerful engine (or two or more) to power a long consist of linked heavy vehicles along the track than it is to have a separate engine for each vehicle. Road vehicles don’t require this because they can be lighter, with rubber wheels on asphalt or concrete for friction, whereas you need heavy steel and a heavy chassis to guarantee enough friction for traction on steel rail.

Since maglev vehicles are frictionless and propelled by guideway current, single vehicles are as efficient in general as multiple-vehicle consists. Despite this advantage, the single-track point-to-point designs of current guideway designs force you into a train mode because you can’t easily and efficiently switch frequent, low-headway individual vehicles back and forth from one track to another while conserving both high frequency and speed. The design of second-generation maglev allows automatic switching that is even more efficient than with existing rail, and comparable to the seamlessness of highway on- and off-ramps but without contact with the guideway. Because of this, you can easily and cheaply construct a dense and efficient network of turnouts impossible with first generation maglevs, that allow the network to handle heavy levels of individual vehicle traffic more comparable to a highway full of buses and trucks than to a railway with passenger and freight trains trying to share the same track — but with all those buses and trucks computer-controlled and guided at the same speed and distance from a central command point.

Second, it’s true that both the German maglev currently in operation in Shanghai (like the similar Korean Rotem and Linimo in Japan) and the American-designed maglev being built between Tokyo and Osaka are propelled by linear motor technology built into the guideway, acting on on-board magnets. But that’s as far as the similarities go.

Only the American/Japanese version uses supercooled superconducting magnets on board. The German/Chinese technology uses electromagnets continuously powered by on-board batteries. As far as propulsion goes, either kind of maglev is what provides the “surfboard effect” where the vehicles are propelled by waves of electric current in the linear motor guideway repelling the on-board magnets in the desired direction. The main difference is the kind of suspension. The German/Rotem/Linimo technology uses electromagnets on arms wrapping around the underside of the guideway; when powered, these are attracted to iron rails on the underside of the guideway. Their natural tendency is to clamp onto the metal, so they need to be continuously controlled by an on-board servomechanism that adjusts the current to the magnets to maintain a 1 cm gap between magnet and rail: this is electromagnetic suspension.

The Japanese, because they live in notably shakey islands, were more attracted to the US design for safety reaons than the Germans were; in this version, “electrodynamic” suspension, the superconducting magnets (far more powerful than electromagnets for the electric current) interact with induced currents in guideway windings to maintain a gap of 10-15 cm from the guideway and the ground — but only above a threshold speed. Until the vehicles are moving at that speed, they must be supported by rubber wheels; while above the threshold, the powerful fields of the superconducting magnets induce currents in guideway windings that automatically generate an equivalent magnetic field that repels the onboard SC magnets. With the “null-flux” guideway loop geometry developed for the SC maglev, any movement of the SC magnets away from equilibrium position with respect to the guidance loops (above threshold speed) automatically induces current (flux) that generates an equal magnetic force repelling the SC magnets back to equilibrium position, where flux in the windings is restored to zero. This is the automatic and inherent failsafe against derailing designed into electrodynamic suspension that was so attractive to the Japanese when they visited Powell and Danby, its inventors, back in the early 1970s.