4. Qingha-i Tibet Railway

The Qinghai-Tibet Railway (青藏鐵路)is honored as a“railway to heaven”as it is the highest“engineering marvel”that has linked Tibet with the rest of China.This railway is the first to connect China properly with the Tibet Autonomous Region, which is the last province-level area in China to have railway due to its altitude and terrain.

The Qinghai-Tibet Railway is 1,956 kilometers long, with 960 kilometers of the track located 4,000 meters above the sea level and the highest point at 5,072 meters.At the same time, the railway passes through China's largest uninhabited land.

The railway has broken several world records.With an elevation of 5,068.63 meters, the Tanggula Railway Station(唐古拉火車站)is the highest railway station in the world.The Fenghuoshan Tunnel (風(fēng)火山隧道), with an elevation of 4,905 meters and a total length of 1,338 meters, is considered to be the world's highest tunnel in a permafrost area.The Kunlun Mountain Tunnel (昆侖山隧道), with 4,648 meters in height and 1,686 meters in length, is the world's longest tunnel in a permafrost area.With a total length of 11.7 kilometers, the Qingshui River Bridge (清水河大橋)is no doubt the longest railway bridge in a permafrost area.

The Tanggula Railway Station is situated in the middle of the Qinghai-Tibet Plateau,600 kilometers away from Lhasa(拉薩). The station was chosen at a place most suitable for passengers to view the Tanggula mountain scenery and take pictures.It is hoped that the Tanggula Railway Station will thus become one of the best scenic spots along the Qinghai-Tibet rail line.

There were and are many technical difficulties for such a railway.About half of the second section was built on barely permanent permafrost.Lack of oxygen is another problem in construction.Trains traveling across the roof of the world have extra oxygen pumped into the cabins to prevent passengers from suffering altitude sickness.