Japan's SCMaglev hit 603 km/h in tests. It won't carry passengers between Tokyo and Nagoya until 2035 at the earliest. Costs have doubled to ¥11 trillion. And the 8-year delay traces back to a single prefectural governor's objection to groundwater.
On 16 April 2015, a Japanese L0 series SCMaglev train hit 603 km/h on the Yamanashi test track — faster than any wheeled or levitated vehicle in railway history, faster than most light aircraft at cruise. The record still stands. The train that set it was supposed to be carrying paying passengers between Tokyo and Nagoya by 2027. That date has now slipped to 2035, at the earliest, and the total cost has doubled to ¥11 trillion ($72 billion).
The story of the Chūō Shinkansen — Japan's SCMaglev mainline — is one of the strangest in modern infrastructure: the world's most technically advanced train, delayed not by any engineering failure, but by one prefecture's concern about its rivers.
What is SCMaglev
Superconducting magnetic levitation (SCMaglev) is fundamentally different from the wheel-on-rail technology used by every Shinkansen, TGV, and ICE. The L0 series train floats 10 cm above a concrete guideway using onboard superconducting magnets cooled to –269°C (near absolute zero) and a linear motor driven by alternating current in guideway coils. There is no contact between the vehicle and the track at operating speed. There is nothing to wear out. Aerodynamic noise replaces mechanical noise.
Commercial operating speed is planned at 500 km/h — compared to 320 km/h for Japan's current fastest Shinkansen. The Tokyo–Nagoya run, 286 km by road, would take 40 minutes. Tokyo–Osaka (504 km) in 67 minutes. The Shinkansen's current Nozomi service does Tokyo–Osaka in 2 hours 22 minutes.
The water dispute that stopped everything
The Chūō Shinkansen needs to tunnel through the Southern Japanese Alps between Kanagawa and Aichi prefectures. Of the 286 km route, roughly 86% will be underground. The Shizuoka section — about 25 km of tunnel through the Akaishi Mountains — passes through the watershed of the Ōi River, one of the main drinking and irrigation water sources for Shizuoka city.
In 2020, the then-governor of Shizuoka Prefecture, Heita Kawakatsu, refused to grant construction approval until JR Central could prove that tunneling would not reduce Ōi River flow. Groundwater in the region percolates through the mountain and emerges as river discharge downstream. Tunneling intercepts that flow. JR Central proposed compensation measures; Shizuoka demanded independent verification. The dispute persisted through multiple governors and five years of negotiations.
In January 2026, new Shizuoka governor Yasutomo Suzuki and JR Central president Niwa signed a letter of agreement: JR Central will pay direct compensation for any measurable reduction in Ōi River water volume. On 26 March 2026, Shizuoka's special environmental committee approved all 28 conservation measures required by the prefecture. Construction in Shizuoka can now proceed — but the years lost to the standoff cannot be recovered.
Cost explosion
When JR Central first filed plans with the national government in 2011, the Tokyo–Nagoya section was projected to cost approximately ¥5.5 trillion. In October 2025, JR Central announced the revised estimate had reached ¥11 trillion ($72 billion) — a doubling driven by harder-than-expected geology in the Akaishi Mountains, escalating material costs, upgraded earthquake resistance standards for deep underground structures, and additional geological reinforcement work required once surveys revealed more complex ground than the original environmental impact assessment assumed.
In January 2026, the Japanese government extended a ¥3 trillion ($28 billion) low-interest loan to JR Central — the first direct government funding for a project that JR Central had long insisted would be privately financed. The loan also unlocked earlier commencement of the Nagoya–Osaka section, now targeting an opening no earlier than 2037.
Is it still worth building?
JR Central's case for SCMaglev has always rested on more than speed. The Tōkaidō Shinkansen — which the Chūō Shinkansen will complement, not replace — carries approximately 150 million passengers per year on the Tokyo–Osaka corridor, the world's busiest intercity rail route. It is critically constrained: frequencies cannot be increased much further. If an earthquake damages the Tōkaidō corridor, Japan has no inland backup for the country's economic spine. The Chūō Shinkansen's mountain route provides that redundancy, regardless of whether passengers actually want to arrive in Osaka in 67 minutes.
Whether the economics hold at ¥11 trillion, without a guaranteed pricing premium that a 500 km/h experience might command, is a question JR Central has not answered publicly. What is certain is that when the train finally does carry passengers — in 2035, 2037, or later — it will be doing so on technology developed entirely by Japan, operating at speeds no other country has approached in revenue service. The wait, for better or worse, is built into the machine.