How do superconducting maglev trains work?

What is superconducting maglev?

Maglev means magnetic levitation: magnetic forces support a vehicle above its guideway, as JR Central's technical overview illustrates [1]. JR Central's superconducting maglev, called SCMaglev, carries superconducting magnets on the train and uses coils mounted along the guideway [1]. At speed, the moving magnets induce currents in levitation and guidance coils, creating magnetic forces that support and center the vehicle [1]. According to JR Central, separate powered propulsion coils provide forward force through a linear motor [1].

Superconductivity makes it possible for the onboard coils to carry persistent current with essentially no electrical resistance in the superconducting state, as JR Central explains [1]. Zero resistance in the winding does not imply a railway that uses no electricity: JR Central describes current supplied to the propulsion coils [1]. JR Central's FAQ explains that the train is propelled by that magnetic force and runs on electricity even when it rolls on its wheels [7]. A meaningful comparison must therefore consider the train, guideway, cooling equipment, and operating conditions rather than only the resistance of the magnet winding [1][2].

JR Central's FAQ also explains that the train is not levitated at every speed: it drives on rubber wheels at low speed and levitates once it exceeds approximately 93 miles per hour, about 150 kilometers per hour, storing the wheels in its body [7]. The induced-current levitation described above depends on motion, so it is weak until the vehicle is moving quickly [1][7].

How do levitation, guidance, and propulsion differ?

JR Central describes levitation and guidance coils installed on both sides of the guideway [1]. When an onboard magnet passes, JR Central explains, it induces current in those coils, whose magnetic field pushes and pulls the vehicle upward [1]. According to JR Central, if the vehicle moves sideways, the guideway coils also provide a centering force [1]. JR Central reports a levitation height of about 10 centimeters for its system [1]. That height is a feature of this railway, not a universal clearance: Transrapid International describes a different gap for its electromagnetic suspension [5].

Propulsion uses a different set of coils, as JR Central explains in its technical overview [1]. JR Central explains that current in guideway propulsion coils creates a magnetic field that attracts and repels the vehicle's superconducting magnets [1]. JR Central likens the arrangement to a rotary motor opened and laid out along the route, with the onboard magnets following the moving field [1]. For normal deceleration, JR Central uses regenerative braking: the linear motors act as generators, converting the vehicle's kinetic energy into electricity that is returned to power conversion equipment [8]. JR Central adds wheel disc brakes and aerodynamic brakes for emergencies [8].

What happened on the Yamanashi test line?

JR Central reports that running tests began on the Yamanashi Maglev Line in 1997 and that the line was renewed and extended to 42.8 kilometers in 2013 [2]. In April 2015, JR Central recorded 603 kilometers per hour with a manned vehicle and 4,064 kilometers of running in a single day [2]. These are separate test results: JR Central presents the distance as cumulative running over the day, not as a claim that the train maintained its record speed for the entire period [2].

The test line supports development work as well as headline speed demonstrations, according to JR Central's integrated report [2]. JR Central's 2025 integrated report describes continued tests of improved Series L0 vehicles and the development of specifications for commercial vehicles [2]. The same JR Central report identifies a planned Chuo Shinkansen operating speed of 500 kilometers per hour [2]. The planned service speed and the Yamanashi record answer different questions: JR Central presents one as an operating objective for a railway and the other as a test-line result [2]. Neither figure alone establishes a journey time or opening date, as the report's separate discussion of project status makes clear [2].

Is the Chuo Shinkansen open?

JR Central describes the Chuo Shinkansen as a project intended to link Tokyo, Nagoya, and Osaka, with the Tokyo-to-Nagoya section promoted first [2]. Its 2025 report says the project was under construction and that the planned 2027 opening could not be met; at that report's publication, JR Central could not predict a new opening date [2]. A successful test ride on the Yamanashi line should not be mistaken for regular end-to-end passenger service on the planned route, as the operator's project description makes clear [2].

The railway is more than a vehicle and a laboratory test track, as JR Central's project report shows [2]. The report discusses stations, tunnels, guideway construction, environmental protection, and coordination with communities along the route [2]. Those activities are part of turning a demonstrated levitation principle into a transport system, according to the operator's account [2]. The report also discusses continuing work on construction, operating, and maintenance costs [2]. The technology's test results do not by themselves settle those project-level questions [2].

Check a report's publication date before relying on its construction update. JR Central's 2025 report says that tunnel excavation had not begun in the Shizuoka section and identifies community discussions and water resources among the concerns [2]. JR Central's account separates an established test capability from the construction and coordination needed for service [2]. Readers looking for an opening date should consult the operator's latest project updates rather than interpret an older planning date as a confirmed schedule.

How is it different from Shanghai's maglev?

Shanghai's Transrapid uses electromagnetic suspension rather than JR Central's superconducting electrodynamic arrangement, according to IEEE Spectrum and JR Central [1][3]. IEEE Spectrum describes the Shanghai vehicle wrapping around its guideway and being lifted toward it by magnetic attraction from electromagnets [3]. Transrapid International explains that electronically controlled electromagnets pull the vehicle toward reaction rails beneath the guideway [5]. Both systems use magnetic forces and a linear motor, but their suspension hardware and operating principles differ, as their respective technical overviews show [1][5].

The Shanghai comparison matters because the word maglev alone does not imply superconductivity, as IEEE Spectrum's description of conventional electromagnets illustrates [3]. JR Central instead specifies superconducting onboard coils for its system [1]. Electromagnetic suspension controls the attraction and the gap, while JR Central's moving-magnet arrangement induces currents in guideway coils [1][5]. The technical overviews show why comparison must also account for distinct guideways, magnets, and cooling requirements [1][5].

What superconductors do maglev trains use?

JR Central identifies niobium-titanium alloy, usually shortened to NbTi, as the conductor in its superconducting magnet coils [1]. JR Central describes cooling these coils with liquid helium to maintain the superconducting state [1]. JR Central's FAQ says the liquid helium is circulated and that the amount consumed is small, and that the high-temperature superconducting magnets under development do not require liquid helium [7]. JR Central's development plan emphasizes cost reduction and further verification of stable operation for high-temperature superconducting magnets [6].

High-temperature superconductors are a separate research direction, as JR Central's development plan shows [6]. National Cheng Kung University's record of a 1997 paper describes a YBCO research prototype operating above a permanent-magnet rail [4]. National Cheng Kung University describes it as a concept-validation prototype, not a commercial railway [4]. That arrangement should not be conflated with JR Central's NbTi magnets and induced-current guideway [1][4]. JR Central also describes developing high-temperature superconducting magnets for potential commercial use and says further verification is needed for stable operation [6].