New Guanjiao Tunnel () is a tunnel on the 2nd line of Qinghai–Tibet Railway in Guanjiao Mountain,

Qinghai province Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also known as Kokonor, is a landlocked province in the northwest of the People's Republic of China. It is the fourth largest province of China by area and has the third smallest pop ...

. It is dual-bored, double-track rail tunnel. The total length of the tunnel is , which makes it the longest railway tunnel in China. 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 . The total construction duration was projected to be 5 years. The tunnel was bored in difficult geological conditions and

high altitude Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...

, exceeding above sea level. The construction started in 2007 and was completed in April 2014. The tunnel was opened on 28 December 2014.新华网: 世界最长高原铁路隧道——逾32公里长的新关角隧道通车
/ref> The tunnel's northeastern portal () is in Tianjun County, the southwestern portal () is in

Ulan County Ulan or Wulan ( Mongolian: ; ; ) is a county of Qinghai Province, China. It is under the administration of Haixi Mongol and Tibetan Autonomous Prefecture Haixi Mongolian and Tibetan Autonomous Prefecture (; mn, ᠬᠠᠶᠢᠰᠢ ᠶᠢᠨ � ...

References

{{commons category, New Guanjiao Tunnel Railway tunnels in China Rail transport in Qinghai