Hakkoda Tunnel Japan

Hakkoda tunnel, with a length of 26.45km, is the longest land based double track railway tunnel in Japan, and sixth longest in the world. It is located in the northern end of Hakkoda Mountain between Tenmabayashi mura and Aomori City in Aomori Prefecture in Japan.The tunnel is part of the Tohoku Shinkansen railway and was sponsored by Japan Railway Construction, Transport and Technology Agency (JRTT). It was built as part of the extension of Tohoku Shinkansen from Hachinohe to Shin Aomori.Tunnel construction began in August 1998 and was completed in February 2005 using the New Austrian Tunnelling Method (NATM). Kajima joint venture built the Otsubo section of the tunnel.