The Seikan Tunnel links Honshu, the main island of Japan, with Hokkaidō, the northern island, by rail way. It’s length is 53.85km, the longest tunnel in the world, with the under sea section 23.3km long. The Tsugaru Kaikyo Line was completed in March of 1985, and the Seikan Tunnel, included within the line, was originally designed for the operation of both Shinkansen and conventional trains by the double gauge track.
At present the tunnel is only used for the conventional train operation because the Shinkansen network project is behind schedule. But Shinkansen is expected to go through the tunnel in the near future. The operation through the Seikan Tunnel shortens the travel time between Honshu and Hokkaidō by providing the weather-free railway network.
