New Guanjiao Tunnel [1](Chinese: 新关角隧道; pinyin: Xīn Guānjiǎo Suìdào) is a tunnel on the 2nd line of Qinghai–Tibet Railway in Guanjiao Mountain, Qinghai province. It is dual-bored, double-track rail tunnel. The total length of the tunnel is 32.645 km (20.285 mi), which made it at the time of completion the longest railway tunnel in China and fourth-longest in the world.
 A portal of New Guanjiao Tunnel during construction in 2011 | |
| Overview | |
|---|---|
| Line | Qinghai–Tibet Railway |
| Location | Guanjiao Mountain |
| Coordinates | 37°8′40″N 99°4′59″E / 37.14444°N 99.08306°E |
| Start | 37°10′58″N 99°10′38″E / 37.18278°N 99.17722°E |
| End | 37°0′33″N 98°52′50″E / 37.00917°N 98.88056°E |
| Operation | |
| Work begun | 2007 |
| Opened | 28 December 2014 |
| Traffic | train |
| Technical | |
| Length | 32,645 metres (107,103 ft) |
| No. of tracks | two single |
| Track gauge | 1,435 mm (4 ft 8+1⁄2 in) |
| Electrified | electrified |
| Operating speed | 160 km/h |
| Highest elevation | 3,381 metres (11,093 ft) |
| Lowest elevation | 3,324 metres (10,906 ft) |
China Railway First Survey and Design Institute is responsible for the design. The New Guanjiao Tunnel was designed for two parallel single-track tunnels with speeds of up to 160 kilometres per hour (99 mph). The total construction duration was projected to be 5 years. The tunnel was bored in difficult geological conditions and high altitude, exceeding 3,300 metres (10,800 ft) above sea level. The construction started in 2007 and was completed in April 2014.[2] The tunnel was opened on 28 December 2014.[3]
The tunnel's northeastern portal (37°11′00″N 99°10′40″E / 37.1834°N 99.1778°E) is in Tianjun County, the southwestern portal (37°00′34″N 98°52′50″E / 37.0094°N 98.8805°E) is in Ulan County.
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