Seikan Tunnel

Seikan tunnel is an undersea tunnel that links Japan’s main island of Honshu with the northern island of Hokkaido. This Japanese tunnel is the second longest in the world with a length of 33.4 miles while Gotthard-Base Tunnel is the longest. This railway tunnel passes beneath the Tsugaru Strait with the track located 140 meters below the sea bed.

On average, 50 trains travel through the tunnel every day. It has two railway stations which are Tappi Kaitei on the Honshu side and Yoshioka Kaitei on the Hokkaido side.


Fast Facts: –

  • The construction work of Seikan tunnel started in 1964 and was completed in 1988.
  • The primary shaft of the tunnel was opened in March 1985 for the very first time.
  • It is the first undersea tunnel ever and the estimated cost of the project is about 6 billion US. Dollars.
  • The construction work was sponsored by the Japanese National Railways.
  • This tunnel was designed with gentle curves and slopes so that it could be used for bullet trains in the future.
  • Initially it consisted of a single gauge track but later it was converted into a double gauge in 2005.
  • The average temperature of the tunnel is maintained at 20°C and humidity between 80 to 90 percent throughout the year.
  • Approximately 23.3 kilometers of the tunnel lie under the seabed which makes it the longest undersea tunnel.
  • It also has the world’s largest maintenance base inside a tunnel with a length of 91 meters, 10 meters in height and width of 16 meters.
  • The tunnel is of limited use because the air transport between the Honshu and Hokkaido is more practicable.