Seikan Tunnel

The Seikan Tunnel (Japanese: 青函トンネル, Seikan Tonneru or 青函隧道, Seikan Zuidō) is a 53.85 km (33.46 mi) dual-gauge railway tunnel in Japan, with a 23.3 km (14.5 mi) portion under the seabed of the Tsugaru Strait, which separates Aomori Prefecture on the main Japanese island of Honshu from the northern island of Hokkaido. The track level is about 100 m (330 ft) below the seabed and 240 m (790 ft) below sea level.[2] The tunnel is part of the standard-gauge Hokkaido Shinkansen and the narrow-gauge Kaikyō Line of the Hokkaido Railway Company (JR Hokkaido)'s Tsugaru-Kaikyō Line. The name Seikan comes from combining the on'yomi readings of the first characters of Aomori (青森), the nearest major city on the Honshu side of the strait, and Hakodate (函館), the nearest major city on the Hokkaido side.

Quick facts: Overview, Location, Coordinates, Status, Star... ▼

Seikan Tunnel

Map of the Seikan Tunnel
Overview
Location	Beneath the Tsugaru Strait
Coordinates	41.3157°N 140.3351°E / 41.3157; 140.3351
Status	Active
Start	Honshu
End	Hokkaido
Operation
Opened	13 March 1988
Owner	Japan Railway Construction, Transport and Technology Agency
Operator	JR Hokkaido
Character	Passenger and freight
Technical
Track length	53.85 kilometres (33.46 mi) 23.3 kilometres (14.5 mi) undersea
No. of tracks	Double track rail tunnel
Track gauge	Dual gauge 1,435 mm (4 ft 8+1⁄2 in) standard gauge (Shinkansen) 1,067 mm (3 ft 6 in) narrow gauge (freight)
Electrified	25 kV AC, 50 Hz
Operating speed	160 km/h (100 mph) 210 km/h (130 mph) for a few days in 2020 and 2021[1] 250 km/h (155 mph) geometrically allowed

The Seikan Tunnel is the world's longest undersea tunnel by overall length (the Channel Tunnel, while shorter, has a longer undersea segment).[3] It is also the second-deepest transport tunnel below the sea level after the Ryfylke Tunnel, a road tunnel in Norway which opened in 2019, and the second longest main-line railway tunnel after the Gotthard Base Tunnel in Switzerland, opened in 2016.[4][5][6]