Megastructures: Extreme Railway: Directed by Martin Gorst and produced by Huge Whitworth, Nina Carbone this Nat Geo documentary tells the story of a railway network built in one of the most extreme environments on earth: The Qinghai -Tibet railway. It took the Chinese engineers almost fifty years to build it, and thousands of lives were lost during the process. However, today it has become the pride of the Chinese railways and one of the best railway networks around the world.
Before climbing up the Tibet plateau the train is fitted with a new engine which provides a combined output of 8000 horse power. To keep the gradient smooth for trains slow ascend dozens of bridges were built, Qingshuihe being the highest one. The greatest difficulty in building the railway came from the permafrost which makes the ground shift and move and destroys the infrastructure. However, this grave problem was also solved by the Chinese scientists with a solution so low-tech that it is hard to believe.
Rocks were embedded to remove the heat from the earth and thus restraining it from shifting. However, this did not end the problem as in some areas the embankments needed some extra help to keep the ground frozen. This help was provided by the thermo siphons. Thus numerous bridges were built on permafrost, including Qingshui (world’s largest permafrost bridge).
As the altitude increases another problem arises, the amount of oxygen in the air decreases. For this, the Lhasa express has the oxygen generating unit which provides the passengers with oxygen-rich air. Moreover, every passenger gets a tube which they can plug directly into the oxygen supply that provides 40 percent of oxygen. Another remarkable structure found here is the Fenghuoshan tunnel which is the world highest railway tunnel. Building it was a life-threatening challenge and thus remarkable medical care was required. Finest medical teams with the latest equipments were summoned and therefore the mortality rate was kept at zero.
With the success of building this railway, Chinese engineers have proven their credibility.
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