Seikan Tunnel（Ja:青函トンネル）is a railway tunnel in Japan. It connects Hokkaido to Aomori Prefecture. This tunnel is second longest transport tunnel in the world. The tunnel is 53.85 km (33.49 miles) long. 23.3 km (14.5 mile) of the tunnel is underwater. There are two stations in a tunnel.
History[change | change source]
The means of transportation from Hokkaido to Honshu was Seikan ship until Seikan tunnel was completed. It took about 3 hours. However, it had some troubles. For example, the sea route wasn't safe. Toyamaru accident in 1954 had 1155 dead and missing person, caused by Typhoon Number 15 Roke. because of that reason, the plan that constructing Seikan Tunnel from Hokkaido to Honshu was becoming a reality. At first, east route and west route was considered. In west route, the deepest depth of water was 140 meter and the nature of the soil was easy to drill rocks, so west route was chosen.
Techniques[change | change source]
We can go through the tunnel by the Bullet Train. Inner structure of the tunnel was planed to make 3 Bullet Train's rails. Because half of this tunnel located under the bottom of the sea, workers who built this tunnel worried about seawater. So, they used new construction techniques. For example, laser measurement, 2150m horizontal drilling, pouring water glass and cement into soft bedrock. These techniques was paid attention by all of the world at that time. There are still much water, so the seawater is collected place in the tunnel and is pumped out of the tunnel.
Station[change | change source]
There are two stations in Seikan tunnel. Tappikaitei Station opened in Aza-Minmayatatsuhama, Sotogahama-machi, Higashitsugaru-gun, Aomori on March 13, 1988. And Yoshiokakaitei Station opened in Tatesaki, Fukushima-cho, Matsumae-gun, Hokkaido on March 13, 1988. If passengers have a special ticket, they can get off the train at then stations to look around. These are located in 149.5 meters under the seabed and there are 2247 steps of stairs to the surface. Also these have the shelter for a train fire and the blackout. Tappikaitei Station and Yoshiokakaitei Station became the service stop each on November 10, 2013 and August 27, 2013. And these stations were abolished on March 15, 2014, because the number of passengers who used these stations, extremely decreased.