is a

railroad Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

tunnel A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube cons ...

Gunma is a prefecture of Japan located in the Kantō region of Honshu. Gunma Prefecture has a population of 1,937,626 (1 October 2019) and has a geographic area of 6,362 km2 (2,456 sq mi). Gunma Prefecture borders Niigata Prefecture and Fukushima P ...

and

Niigata Prefecture is a prefecture in the Chūbu region of Honshu of Japan. Niigata Prefecture has a population of 2,227,496 (1 July 2019) and is the fifth-largest prefecture of Japan by geographic area at . Niigata Prefecture borders Toyama Prefecture and ...

s of Japan, operated by JR East

Jōetsu Line The is a major railway line in Japan, owned by the East Japan Railway Company (JR East). It connects Takasaki Station in Gunma Prefecture with Miyauchi Station in Niigata Prefecture, linking the northwestern Kanto region and the Sea of Japan c ...

. The name originates from the Shimizu mountain pass nearby. There are three tunnels near each other, which are the Shimizu Tunnel, the Shin-Shimizu Tunnel, and the Dai-Shimizu Tunnel.

Shimizu tunnel

The Shimizu tunnel is the oldest of the three, opened in 1931 after nine years of construction. The length of the tunnel is 9,702 m, and has a

single track Single may refer to: Arts, entertainment, and media * Single (music), a song release Songs * "Single" (Natasha Bedingfield song), 2004 * "Single" (New Kids on the Block and Ne-Yo song), 2008 * "Single" (William Wei song), 2016 * "Single", by ...

. Because of technical difficulties at the time, a spiral was built, with a diameter of 800 m. This tunnel was the longest in Japan at the time.Website on Shimizu tunnel
The construction improved the journey time between Niigata and

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and List of cities in Japan, largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, ...

, decreasing it by 4 hours since trains no longer needed to go through the

Usui Pass The is a mountain pass that lies between Nagano and Gunma prefecture in Japan. It has served as one of the major transportation routes in central Japan since at least the eighth century. Road The pass on the ancient Tōsandō highway was d ...

.Toei Hotel introduction to Yuzawa and Joetsu Line
/ref> Because the tunnel was too long to be suitable for

steam locomotives A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...

, the tracks in and around the tunnel were electrified from the beginning.

Shin-Shimizu tunnel

The Shin-Shimizu tunnel was made in 1967 to make the line double track, because of a high demand of transportation on the Joetsu line. The tunnel is 13,500 m long.

References

{{Asia-tunnel-stub Railway tunnels in Japan Tunnels completed in 1931