字幕列表 影片播放 列印英文字幕 Switzerland has nearly finished an incredible feat of engineering: the world’s longest railway tunnel. So to get a better sense of that accomplishment, these are the top ten world’s longest MegaTunnels. When Japan’s Iwate-Ichinohe opened in 2002 it claimed the title of world’s longest land-based railway tunnel. Part of the Tohoku Shinkansen high speed rail line, it passes through hilly terrain near the Kitakami and Ou mountains. The ninth longest railway tunnel is also on Japan’s high speed rail line. Shooting through the Hakkoda mountain range, the Hakkoda tunnel is the world’s longest operating double-tracked land-based tunnel, and for two months held the overall title of world’s longest terrestrial tunnel until it was surpassed by the fifth ranked tunnel on this list. Part of China’s mind-boggling 20,000 kilometers of operating high speed rail lines, the Taihang tunnel connects the capital of Hebei province with the capital of Shanxi province through the Taihang mountains, cutting travel time between the two cities from almost six hours to just one. The Sierra de Guadarrama mountain range in the Iberian peninsula is home to Spain’s longest railway tunnel, the double-tube Guadarrama. Which carries high speed rail passengers on their way to Madrid through 28 miles of darkness. China’s longest railway tunnel -- and the sixth longest on this list -- is the Guanjiao which opened last December after seven long years of high altitude construction at more than 10,000 feet above sea level, because this line impressively traverses the Tibetan Plateau. Although it won’t be operational until 2022, Austria’s Koralm MEGA-Tunnel demands mentioning on this list. It’s two parallel tunnels will at times run at depths of more than 4,000 feet below ground. That’s a whole lotta mountain! And the current titleholder for world’s longest land tunnel is the LBT, passing through the Alps of Switzerland. About 110 trains use the Lötschberg every day, 80 of them freight. The LBT actually sits some 400 meters below the original Lötschberg Tunnel, which is over a century old, but still fully operational. The top three tunnels are in a class of their own, starting with the Chunnel which connects the United Kingdom with the European mainland in France under the English Channel. The Channel Tunnel carries both Eurostar passenger trains and the Eurotunnel Shuttle for road vehicles and has the longest undersea section of any tunnel in the world. Completed in 1988, the world’s second-longest tunnel is the Seikan tunnel, which connects the main Japanese island of Honshu with the northern island of Hokkaido beneath the Tsugaru Strait. The track level is about 100 meters below the seafloor. And the longest tunnel in the world, set to be fully operational in 2016, is Switzerland’s Gotthard Base Tunnel. It’s main purpose is to increase total transport capacity across the Alps, especially for freight, and to shift freight volumes from road to rail to reduce fatal accidents and environmental damage caused by ever-increasing numbers of heavy trucks. Thanks for watching this episode of TDC. Make sure to hit that like button to help us spread this video if you enjoyed it, and be sure to subscribe and join the conversation if you haven’t yet.