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| Fig. 1: Chuo Shinkansen under construction (Source: Wikimedia Commons) |
The Chuo (central) Shinkansen is a Japanese superconducting maglev line planned to open around 2035 between Tokyo (Shinagawa) and Nagoya. [1] (See Fig. 1.) With an operating speed of 500 km/h, it is expected to cover the ~286 km Shinagawa-Nagoya section in ~40 min. [1] At maturity, Japan Railways (JR) indicate ~1000 seats per 16-car train. [2] By contrast, the current fastest Tokyo-Nagoya service is Nozomi (N700 family) on the Tokaido Shinkansen, covering ~366 km in ~86 min with a maximum operating speed of 285 km/h. [3] Including other services (Hikari, Kodama), the Tokaido Shinkansen operates >15 trains/hour in peak patterns, and the N700S 16-car formation provides ~1314 seats per train. [3]
The Chuo Shinkansen uses electrodynamic suspension (EDS) and long-stator linear synchronous motor (LSM) propulsion, which reduces wheel-rail rolling losses by levitating the train. [1] Each bogie carries niobium-titanium (Nb-Ti) superconducting coils cooled to -269°C, enabling persistent currents and strong magnetic fields for levitation and guidance without continuous power to the onboard coils. [1] The guideway contains levitation/guidance coils and propulsion coils as well as position-sensing technology that energizes only the coil blocks adjacent to the vehicle so the LSMs traveling field pulls from ahead and pushes from behind to propel the train. [1]
A metric for assessing the energy efficiency of transportation is watt-hour/seat/km, the amount of energy used by one seat of passenger every kilometer of travel. The energy efficiency of an N700 train of the Tokaido line cruising at 285 km/h (such as Nozomi) is estimated to be 70 Wh/seat/km, while the Chuo Shinkansen cruising at 300 km/h is estimated to be 53 Wh/seat/km. [4] Chuo Shinkansen traveling at its maximum speed of 500 km/h operates at an estimated 99 Wh/seat/km. [4] These reported values from Fritz et al. suggest that while magnetic-levitation technology enables faster travel time between Tokyo and Nagoya, it does not offer a more energy-efficient alternative.
While magnetic levitation may appear more efficient because it removes the rolling resistance of wheels, it experiences a larger drag force as an inevitable consequence of greater speed. This is exemplified by the relationship linking drag force to speed:
where ρ is the density of air, CD is the drag coefficient determined by design of the train, and A is the front area.
The drag force a train must overcome scales with the square of speed. Comparing the Chūō Shinkansen at 500 km/h (139 m/s) with a Nozomi (N700 series) at 300 km/h (83 m/s), the Chūō Shinkansen faces (139/83)2 ≈ 2.8 times greater drag and thus requires about 2.8× more energy per unit distance. Drag is further increased in tunnels by the piston effect, where pressure builds in front of the train. Because roughly 90% of the Chūō Shinkansen route is in tunnels, the 2.8× figure is likely a lower bound on the efficiency improvement that maglev technology must achieve to match the current N700 Shinkansen's energy efficiency at 500 km/h. [5]
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| Table 1: Tokyo-Nagoya service comparison between N700 series and Chuo Shinkansen. [1-4] |
JR Central currently estimates ~11 trillion yen to construct the Shinagawa-Nagoya section. [6] Although JR Central bears construction in principle, public loans were extended to support the project. [7] Shizuoka Prefecture has withheld key permits for the tunnel under the Ōi River catchment (no station in the prefecture), citing water resource and ecological risks, contributing to delays and the shift of opening into the 2030s. [8] This debate connects to a broader Japanese policy tension: large inter-prefecture trunk investments vs. sustaining local/regional rail and economies, with critics arguing trunk focus can favor major metros and accelerate rural depopulation if not balanced by local investment.
© Kent Kotaka. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] "The Review: Superconducting MAGLEV (SCMAGLEV)," Central Japan Railway Company, May 2017.
[2] S. Andersen, "The Chuo Shinkansen Project: High Speed Rail in Japan," Asia-Pac. J. Jpn Focus 17, 5327 (2019).
[3] "Integrated Report 2024," Central Japan Railway Company, 2024.
[4] E. Fritz et al. "Energy Consumption of Track-Based High-Speed Transportation Systems: Maglev Technologies in Comparison With Wheel-Rail Systems," Transp. Syst. Technol. 4, 134 (2018).
[5] "リニア中࣫ 0;新 幹線の整備状況について," Ministry of Land, Infrastructure, Transport and Tourism, Railway Bureau, 30 Jan 2024 [Regarding the progress of L0 series Maglev train construction].
[6] "Notice Concerning Total Construction Costs for the Chuo Shinkansen Section Between Shinagawa and Nagoya," Central Japan Railway Company, 29 Oct 25.
[7] "Fifth Long-Term Loan from the Japan Railway Construction, Transport and Technology Agency," Central Japan Railway Company, 10 Jul 17.
[8] J. Klühspies and M. Hekler, "A Maglev, a Tunnel, a River. On the Delays in the Realization of the Tokyo-Nagoya Maglev Line," Transp. Syst. Technol. 6, 31 (2020).
