Taihang Tunnel (Chinese: 太行山隧道; pinyin: Taihang Shan Suidao) is the third-longest (after New Guanjiao and West Qinling) mountain railway tunnel in China. It is a double track tunnel, and was built to allow the Shitai Passenger Railway to cross the Taihang Mountains. The left track is 27,839 metres long and the right one is 27,848 metres long. The tunnel was finished on Dec 22, 2007.
The Shitai Passenger Railway is the high speed railway line linking Shijiazhuang, the capital of Hebei province, and Taiyuan, the capital of Shanxi province. After the opening of Taihang Tunnel and completion of the high-speed railway, the travel time from Shijiazhuang to Taiyuan went down from almost six hours to one hour.
References
Taihang Tunnel Wikipedia(Text) CC BY-SA