Magnetschwebebahn: Schweben auf Magnetismus

The Train That Does Not Touch the Track

In every railway system in the world, the train's wheels roll on the rails. This contact is what makes railways railways — the low rolling resistance of steel wheel on steel rail is precisely why trains are so energy-efficient compared to road vehicles. But that contact is also a limiting factor. At very high speeds, the dynamic forces at the wheel-rail interface produce vibration, noise, and wear. Maglev — magnetic levitation — eliminates the wheel-rail contact entirely, raising the possibility of transportation at speeds that conventional railways cannot approach.

Two fundamentally different physical principles can achieve magnetic levitation for railway vehicles, and the two main commercial maglev systems in the world use different approaches.

Electromagnetic Suspension: The Transrapid Approach

Electromagnetic suspension (EMS) is the principle behind the Transrapid system developed in Germany and used in the Shanghai Maglev. In this approach, the vehicle wraps around a guideway from below. Electromagnets on the underside of the vehicle are attracted upward towards ferromagnetic reaction rails on the underside of the guideway structure. The vehicle literally hangs from the guideway, attracted upward into it.

The fundamental challenge of EMS is instability. Electromagnetic attraction between two objects increases as they get closer together — a classic unstable equilibrium. Without control, an EMS vehicle would simply crash into its guideway. Stable levitation requires a sophisticated active control system that continuously measures the gap between the vehicle magnets and the guideway rail (typically around 10 mm) and adjusts magnet current hundreds of times per second to maintain that gap against all disturbances. This control system is safety-critical: a failure that causes the gap to collapse would result in the vehicle contacting the guideway.

Propulsion in the Transrapid uses a linear motor. Rather than a rotating motor driving wheels, a linear motor is effectively a rotary motor "unrolled" flat. The stator — the part that generates the travelling magnetic field — is laid along the guideway. The rotor — the part that responds to the magnetic field and is pulled along — is on the vehicle. By controlling the speed of the travelling magnetic field in the stator, the control system precisely regulates vehicle speed.

Electrodynamic Suspension: Japan's SCMaglev

Electrodynamic suspension (EDS), used by Japan's SCMaglev (superconducting maglev) system, operates on a completely different principle: magnetic repulsion rather than attraction. Superconducting magnets on the vehicle induce currents in conducting coils in the guideway walls as the vehicle moves. Those induced currents generate their own magnetic fields that repel the vehicle's magnets, pushing the vehicle away from the guideway walls and floor — levitating it.

EDS has a significant inherent advantage: it is stable. If the vehicle moves closer to the guideway, the induced currents increase and the repulsion force increases, pushing it back. This self-correcting behaviour means that EDS does not require the split-second active control that EMS demands for stability, though precision electronic control is still needed for guidance and speed regulation.

The superconducting magnets used in JR's system are the key to its capability. By cooling the magnet coils to near absolute zero using liquid helium (and in newer generations, liquid nitrogen), electrical resistance drops to zero and the magnets can carry enormous currents — generating magnetic fields far stronger than conventional electromagnets — without consuming power (beyond what is needed for cooling). These powerful fields allow the vehicle to levitate at a large gap of around 100 mm, compared to the 10 mm of EMS, and to travel through a guideway that surrounds it on the sides as well as the bottom for guidance.

The one disadvantage of EDS is that repulsion requires the vehicle to be moving — induced currents only exist when there is relative motion. Below about 150 km/h, the SCMaglev relies on retractable rubber-tyred wheels for support, retracting them as levitation speed is reached.

Shanghai Maglev: The World's Fastest Commercial Train

The only commercial EMS maglev line open to regular passengers is the Shanghai Maglev Train (SMT), which connects Pudong International Airport to the Longyang Road metro station in Shanghai. Operating since 2004, the line covers 30 kilometres in approximately 7 minutes and 20 seconds at a maximum commercial operating speed of 431 km/h — the fastest commercial rail service in the world by a substantial margin.

The Shanghai Maglev uses the German Transrapid TR08 technology. The guideway is an elevated structure, and the trains run at speeds that conventional rail technology cannot approach on the relatively short route. Passengers experience a smooth, quiet, vibration-free journey — the absence of wheel-rail contact eliminates the rumble and oscillation of conventional trains. At 431 km/h, the journey feels less like a train ride and more like a commercial aircraft immediately after takeoff.

Despite its impressive performance, the Shanghai Maglev has remained an isolated demonstration rather than the first link in a national network. Extending the line into Shanghai's city centre or connecting it to other cities would require enormous infrastructure investment in technology incompatible with China's extensive conventional and high-speed rail network.

JR Chuo Shinkansen: The Future of Maglev?

Japan's Central Japan Railway Company (JR Central) is constructing the Chuo Shinkansen, a superconducting maglev line that will eventually connect Tokyo (Shinagawa) and Osaka, a distance of approximately 438 kilometres. The first phase, from Shinagawa to Nagoya (286 km), was under construction through the 2020s with an opening date targeted for around 2027, though regulatory and construction challenges have created delays.

The Chuo Shinkansen will operate at a commercial speed of 500 km/h, reducing the Tokyo-Nagoya journey time from around 85 minutes on the existing Shinkansen to about 40 minutes. In test runs on the Yamanashi Maglev Test Line, JR's L0 series test train reached 603 km/h in 2015 — the current absolute world speed record for any rail vehicle.

The Chuo Shinkansen represents an extraordinary investment: the Tokyo-Nagoya section alone is projected to cost over 9 trillion yen (approximately US$65 billion), much of it driven by the need for an almost entirely tunnel-based route through mountainous terrain between the two cities. JR Central has committed to financing the construction largely from its own resources and Shinkansen revenues, an unusual approach that reflects both the company's financial strength and the strategic importance of the route.

Why Maglev Has Not Replaced Conventional Rail

Given maglev's impressive speed capabilities, it is reasonable to ask why it has not become the dominant railway technology. The answer lies in a combination of economics, network effects, and the extraordinary success of conventional high-speed rail.

Maglev infrastructure is completely incompatible with conventional rail. A maglev guideway is not a track that a conventional train can use, and a maglev vehicle cannot run on conventional track. This means that every new maglev line must be built entirely from scratch — there is no possibility of sharing infrastructure with existing railways, and no existing fleet of maglev vehicles can be redirected to a new line. The network effects that make conventional rail powerful — thousands of trains connecting thousands of stations across a shared network — simply do not exist for maglev.

The cost per kilometre of maglev infrastructure is also substantially higher than even high-speed rail, which is itself enormously expensive. The combination of novel technology, precision engineering requirements, and complete new-build necessity means that maglev can only be justified for the highest-demand corridors where the speed premium justifies the investment.

Meanwhile, conventional high-speed rail operating at 300 to 350 km/h has proven highly competitive with aviation on corridors of 300 to 800 kilometres, carries hundreds of millions of passengers annually, and continues to expand its network. For the routes where HSR works well, the marginal benefit of maglev's additional speed does not justify the additional cost. Maglev's most plausible role is in corridors where extreme speed genuinely matters — very long routes, or airport links where 7 minutes versus 20 minutes makes a significant difference.

For a broader view of where high-speed rail technology may be heading, see our guide to the future of high-speed rail.