Shin-Kanmon Tunnel

The Shin-Kanmon Tunnel (Japanese: 新関門トンネル) is a 18.713-kilometre-long (11.628 mi) undersea railway tunnel under the Kanmon Straits connecting Shin-Shimonoseki Station on the Japanese island of Honshu and Kokura Station on Kyushu.^[1] At the time of opening in March 1975, it was the longest railway tunnel in Japan before being overtaken by in 1988 the opening of the Seikan Tunnel.

• Starting point: Ichinomiya Gakuencho, Shimonoseki City, Yamaguchi Prefecture
• End point: 2-chome, Shimotomino, Kokurakita-ku, Kitakyūshū, Fukuoka
• Overall length: 18,713 metres (11.628 miles)
• Undersea bed section: 880 metres (960 yd)
• Below sea level section: 66 metres (72 yd)
• Tunnel gradient: 18/1000
• Track gauge: 1,435 mm
• Electrification: 25 kV AC, 60 Hz, overhead catenary

The construction of the new tunnel started as a project to connect Honshu and Kyushu with a high-speed railway. The tunnel was constructed at the shortest section in the Kanmon Strait between Dannoura, Shimonoseki City - Mekari, Mojiku, Kitakyushu. Although the entire Shin-Kanmon Tunnel is 5 times longer, the undersea section is shorter than the conventional line Kanmon Tunnel (the Kanmon Tunnel undersea bed section is 1,140-metre (1,250 yd) long).

There is a 1,000 km (620-mile) distance marker about 1.8 km (1.1 miles) from the middle point of the tunnel. This is the only 1000 km railway marker in Japan.

• Shimonoseki entrance: 34°00′11″N 130°56′53″E / 34.003093°N 130.948167°E / 34.003093; 130.948167
• Moji entrance: 33°52′58″N 130°53′55″E / 33.882837°N 130.8985°E / 33.882837; 130.8985