China opens world's highest railway tunnel

The world's highest tunnel for high-speed trains is now open in northwest China.

At an altitude of 3,607.4 metres, the 16.3-km-long tunnel will link Gansu and Xinjiang provinces. 

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One of the most daunting engineering projects, the tunnel which passes through the Qilian Mountains, also has a bridge. 

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It is expected to reduce the travel time between Lanzhou and Urumqi to eight hours from about 20 hours. 

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The Lanxin (Lanzhou-Xinjiang) High-Speed Rail Line, also known as the Lanzhou-Urumqi High-Speed Railway is a 1,776 km high-speed line expected to be completed by 2015.

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The $23 billion railway is one of the major infrastructure projects in China.