場所青森 青函トンネル 羅保派

The Seikan Tunnel is a 53.85 km (33.46 mi) dual-gauge railway tunnel in Japan, connecting Aomori Prefecture on Honshu with Hokkaido under the Tsugaru Strait. It is the world's longest undersea tunnel by overall length, with a 23.3 km (14.5 mi) section beneath the seabed. Construction began in 1964 and completed in 1988, involving significant engineering challenges and the loss of 34 lives. The tunnel accommodates both high-speed Shinkansen and freight trains, though logistical challenges exist due to differing train speeds.