Seikan Tunnel

Seikan Tunnel
Train approaching Tappi-Kaitei Station in July 2008
Overview
LocationBeneath the Tsugaru Strait
Coordinates41°18′57″N 140°20′06″E / 41.3157°N 140.3351°E / 41.3157; 140.3351
StatusActive
StartShiriuchi, Hokkaido
(41°35′32″N 140°19′19″E / 41.592278°N 140.321806°E / 41.592278; 140.321806 (Hokkaido Portal))
EndImabetsu, Aomori Prefecture, Honshu
(41°10′39″N 140°27′30″E / 41.177611°N 140.458333°E / 41.177611; 140.458333 (Honshu Portal))
Operation
OpenedMarch 13, 1988 (1988-03-13)
OwnerJapan Railway Construction, Transport and Technology Agency
Operator JR Hokkaido
CharacterPassenger and freight
Technical
Line length
  • 53.85 km (33.46 mi)
  • 23.3 km (14.5 mi) undersea
No. of tracks2
Track gauge
  • Dual gauge:
  • 1,435 mm (4 ft 8+12 in) standard gauge for Shinkansen
  • 1,067 mm (3 ft 6 in) narrow gauge for freight
ElectrifiedOverhead line25 kV 50 Hz AC
Operating speed
  • Normal: 160 km/h (100 mph)
  • During major holidays: 260 km/h (160 mph)
Route map

The Seikan Tunnel (Japanese: 青函トンネル, Seikan Tonneru or 青函隧道, Seikan Zuidō) is a 53.85-kilometre (33.5-mile) dual-gauge railway tunnel in Japan, with a 23.3-kilometre (14.5-mile) segment running beneath the seabed of the Tsugaru Strait, which separates Aomori Prefecture on Honshu, Japan's main island, from the northern island of Hokkaido. The tunnel's track level lies approximately 100 metres (330 ft) below the seabed and 240 metres (790 ft) below sea level. Following several decades of planning and construction, the tunnel opened on 13 March 1988.

The Seikan Tunnel forms part of the standard-gauge Hokkaido Shinkansen as well as the narrow-gauge Kaikyō Line operated by the Hokkaido Railway Company (JR Hokkaido). Its name, "Seikan," is derived from the on'yomi readings of the first characters of Aomori (青森), the nearest major city in Honshu, and Hakodate (函館), the nearest major city in Hokkaido.

By total length, the Seikan Tunnel is the world’s longest undersea tunnel, surpassing even the Channel Tunnel (although the latter has a longer undersea section). It is also the second deepest transport tunnel below sea level and was the deepest until Norway's Ryfylke Tunnel opened in 2019. It is the second longest main-line railway tunnel following Switzerland’s Gotthard Base Tunnel, which began operations in 2016.