[JP] First Major Tunnel Breakthrough Achieved on Chuo MaglevLine

[Miss Maglev]

Milestone for Maglev: First Major Tunnel Breakthrough Achieved on Chuo Shinkansen Line

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2025-05-12_First Major Tunnel Breakthrough

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ＪＲ東海が工事を進めるリニア中央新幹線伊那山地トンネルの戸中・壬生沢工区で、隣接する坂島工区への貫通部分を指さす関係者＝１３日午後、長野県豊丘村

A JR Central official points to the breakthrough section connecting the Tonaka-Mibusawa work zone with the adjacent Sakashima section of the Ina Mountain Tunnel, part of the Chuo Shinkansen maglev line under construction — May 13, Toyooka Village, Nagano Prefecture.
Photo: https://www.jiji.com/jc/article?k=2025051301157&g=eco Accessed 2025-05-13

On May 13, JR Central (JR Tokai) announced that two sections of the Ina Mountain Tunnel on the Chuo Shinkansen maglev line in Nagano Prefecture—Tonaka/Mibusawa and the adjacent Sakashima section—have been successfully connected. This marks the first breakthrough between two mainline tunnel sections (excluding the Yamanashi maglev test track). During a media visit that day, a 2-meter-high, 5-meter-wide opening at the breakthrough site was visible.

Excavation of the Tonaka/Mibusawa section began in November 2022. The team dug approximately 2.7 kilometers eastward from the center of the section before connecting to the Sakashima side on May 12 using heavy machinery.

The Ina Mountain Tunnel spans about 15.3 kilometers, running east to west through the villages of Toyooka and Oshika in Nagano. The project is divided into three sections, with completion of civil engineering work targeted for the winter of 2031.

Info based on https://www.jiji.com/jc/article?k=2025051301157&g=eco Accessed 2025-05-13

[latestnews]

Breakthrough Achieved in Linear Chuo Shinkansen Tunnel in Nagano’s Ina Mountains

On May 13, JR Central announced a significant milestone in the construction of the Linear Chuo Shinkansen: two sections of the Ina Mountain Tunnel in Nagano Prefecture have successfully connected. The breakthrough joins the Tonaka–Mibusawa section (approx. 6.6 km) with the Sakashima section (approx. 5.1 km), forming part of the full 15.3 km tunnel.

This is the first time adjoining tunnel segments—excluding the maglev test track—have been joined on the main line. The breakthrough point, located in Toyooka Village, features a 2–3 meter thick rock wall now opened with a hole approximately 2 meters high and 5 meters wide.

Kazuyuki Koike, head of JR Central’s Nagano construction office, described the achievement as “a major milestone,” pledging to continue steady progress toward the project’s completion.
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2025-05-19_Nagano

9d86f96e8322d0bf929a9453792af167_1[1].jpg (22.07 KiB) Viewed 166 times

Photo https://www.sanyonews.jp/photo/detail?a ... id=1723368 Accessed 2025-05-19

[Miss Maglev]

The article from Shinano Mainichi Shimbun, titled "リニア工事現場でトンネル貫通　長野・豊丘村、報道陣に公開" ("Tunnel Breakthrough at Linear Construction Site in Toyooka Village, Nagano, Opened to the Press"), reports on the recent breakthrough of the Ina Mountain Tunnel's two construction sections in Nagano Prefecture.

Key Highlights:

Tunnel Breakthrough: On May 12, 2025, Central Japan Railway Company (JR Central) announced the successful connection of two sections of the Ina Mountain Tunnel, part of the Chūō Shinkansen maglev line. This marks the first time that mainline tunnel sections have been connected, excluding the Yamanashi maglev test line.

Construction Details: The Tonaka-Mibusawa section began excavation in November 2022. Approximately 2.7 kilometers were excavated eastward from near the center of the section, reaching the adjacent Sakashima section. On May 13, a hole measuring about 2 meters in height and 5 meters in width was opened, and the site was made accessible to the press.

Project Timeline: The Ina Mountain Tunnel spans approximately 15.3 kilometers, crossing east-west through Toyooka Village and Ōshika Village in Nagano Prefecture. The tunnel is divided into three sections, with civil engineering work expected to be completed by the winter of 2031.

This milestone is significant for JR Central's Chūō Shinkansen project, aiming to connect Tokyo and Nagoya with a high-speed maglev line.

Info based on https://www.shinmai.co.jp/news/article/ ... 5053100115 Accessed 2025-05-31