xizhimen
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World miracle:Running on the roof of the world，Qinghai–Tibet railway
Chinese engineering miracle
The total length of Qingzang railway is 1956 km. The line includes the Tanggula Pass, at 5,072 m (16,640 feet) above sea level the world's highest rail track. The 1,338 m Fenghuoshan tunnel is the highest rail tunnel in the world, at 4,905 m above sea level. The 3,345-m Yangbajing tunnel is the longest tunnel on the line. It is 4,264 m above sea level, 80 kilometres north-west of Lhasa.
More than 960 km, or over 80% of the Golmud-Lhasa section, is at an altitude of more than 4,000 m. There are 675 bridges, totalling 159.88 km, and about 550 km of the railway is laid on permafrost.
There were and are many technical difficulties for such a railway. About half of the second section was built on barely permanent permafrost. In the summer, the uppermost layer thaws, and the ground becomes muddy. Chinese engineers dealt with this problem by building elevated tracks with foundations sunk deep into the ground, building hollow concrete pipes beneath the tracks to keep the rail bed frozen, and using metal sun shades.[12] Similar to the Trans-Alaska Pipeline System portions of the track are also passively cooled with ammonia based heat exchangers.
The air in Tibet is much thinner, having 35% to 40% less oxygen than at sea level. Special passenger carriages are used, and several oxygen factories were built along the railway. At this altitude in these latitudes, water in toilets must be heated to prevent freezing. The Chinese government claimed that no construction worker died during the construction due to altitude sickness related diseases. [13] The railway passes the Kunlun Mountains, an earthquake zone. A magnitude 8.1 earthquake struck in 2001. Dozens of earthquake monitors have been installed along the railway.
As the lack of oxygen is the primary threat to passenger health, two systems are employed to supply enough oxygen throughout the train. Firstly, oxygen dispersed into the carriages ensures the oxygen requirement of passengers. Secondly, oxygen masks conveniently located beside each seat are also available should anoxia appear. Doctors on the trains also offer expert medical treatment both day and night.
Chinese engineering miracle
The total length of Qingzang railway is 1956 km. The line includes the Tanggula Pass, at 5,072 m (16,640 feet) above sea level the world's highest rail track. The 1,338 m Fenghuoshan tunnel is the highest rail tunnel in the world, at 4,905 m above sea level. The 3,345-m Yangbajing tunnel is the longest tunnel on the line. It is 4,264 m above sea level, 80 kilometres north-west of Lhasa.
More than 960 km, or over 80% of the Golmud-Lhasa section, is at an altitude of more than 4,000 m. There are 675 bridges, totalling 159.88 km, and about 550 km of the railway is laid on permafrost.
There were and are many technical difficulties for such a railway. About half of the second section was built on barely permanent permafrost. In the summer, the uppermost layer thaws, and the ground becomes muddy. Chinese engineers dealt with this problem by building elevated tracks with foundations sunk deep into the ground, building hollow concrete pipes beneath the tracks to keep the rail bed frozen, and using metal sun shades.[12] Similar to the Trans-Alaska Pipeline System portions of the track are also passively cooled with ammonia based heat exchangers.
The air in Tibet is much thinner, having 35% to 40% less oxygen than at sea level. Special passenger carriages are used, and several oxygen factories were built along the railway. At this altitude in these latitudes, water in toilets must be heated to prevent freezing. The Chinese government claimed that no construction worker died during the construction due to altitude sickness related diseases. [13] The railway passes the Kunlun Mountains, an earthquake zone. A magnitude 8.1 earthquake struck in 2001. Dozens of earthquake monitors have been installed along the railway.
As the lack of oxygen is the primary threat to passenger health, two systems are employed to supply enough oxygen throughout the train. Firstly, oxygen dispersed into the carriages ensures the oxygen requirement of passengers. Secondly, oxygen masks conveniently located beside each seat are also available should anoxia appear. Doctors on the trains also offer expert medical treatment both day and night.
