Why is Qinghai-Tibet Railway a world wonder?

The famous highest railway in the world, Qinghai-Tibet Railway is reputed as a man-made world wonder and attracts thousands of travelers to take a train to Tibet from Beijing, Shanghai, Chengdu, etc. Why? It is not merely because it is the world’s highest railway, but also because that the railway is built on the land that many international experts thought it was impossible. So what were the challenges of building this railway to Tibet? The followings are the four major challenges Chinese engineers tackled in constructing the Qinghai-Tibet Railway.   

 

High altitude

 

High altitude is a great risk for travelers who travel to Tibet for the first time, let alone the constructors of the Qinghai-Tibet Railway who had to do heavy work. The oxygen content along the railway is only 50-60 percent of that at sea level as some 960 km of tracks are built on plateau - more than 4,000 meters above sea level. The highest point reaches 5,072 meters, which made it the world's highest railway. Therefore, the workers had to shoulder oxygen bottles to get to work.

 

The high altitude also makes low temperature along the Qinghai-Tibet Railway. The annual average temperature on some construction sites is below zero degrees Celsius with the lowest temperature at -45 degrees Celsius.

 

Permafrost and wetland

 

As we know, the Qinghai-Tibet Railway is also known as the longest track on frozen earth. There is as long as 550 kilometers of the Qinghai-Tibet Railway constructed on the permafrost which features soft and wet soil in summer, hard and stretching in winter and is a great trouble for all engineers in the world.

 

To solve this problem, engineers used stone embankment - a layer of loosely piled chunks of granite about the size of baseballs that allows enough space between the rocks for air to circulate freely. In some places, the engineers bury ventilation pipes in the ground. The pipes simply allow the cold air to circulate underneath the rail-bed. In other spots, though, a pipe called a thermosiphon is sunk 5 meters (15 feet) into the ground and filled at the bottom with ammonia. The ammonia becomes gas at a low temperature, giving off a vapor that draws heat from the bottom of the tube and flushes it out the top, cooling at the same time.

 

Building a bridge over the permafrost is the most expensive way to have the least impact on the area. The 11.7km Qingshuihe Bridge at Hoh Xil is the world-longest bridge built on the permafrost. If tourists travel to Tibet by train, it should be a notable place during the Tibet train tour.   

 

Fragile ecosystem

 

The ecosystem on the Qinghai-Tibetan plateau is quite fragile. There are many rare animals and plants on the plateau, such as Tibetan antelope, Kiang, black-necked cranes. Protection of the ecological environment should be the first concern in the design of the Tibet Railway. Thus, the track must avoid the major habitats of wild animals. If it was impossible to keep away from the habitats, other solutions must be figured out. For example, 25 passageways for wild animals based on their migration habit were built along the Qinghai-Tibet Railway to minimize disturbance to the nature reserves for endangered animals when the train to Tibet is in operation. Besides, engineers also figured out ways to prevent damage to permafrost and wetlands.

 

All waste water from construction and camp sites was also processed to meet the corresponding sewage treatment standard before discharge. Solid waste from construction sites and trash from campsites was sorted out and recycled whenever possible. Waste and trash that cannot be degraded was moved to appropriate places for batch treatment.

 

Train to Tibet

 

All the Tibet trains were also tailor-made according to the environment of the Qinghai-Tibet Railway. All the trains to Tibet were installed with environment-friendly toilets, wastewater deposit tanks and garbage treatment facilities to protect environment along the railroad.

 

The train to Tibet is totally sealed, air-conditioned and equipped with special facilities, such as supercharging system, oxygen supply, altitude display, etc. Tourists who travel to Tibet by train would feel very comfortable on the train to Tibet.