China's 1,956-kilometer Qinghai-Tibet Railway, the world's highest rail system at an elevation of about 4,000 meters, is being threatened by desertification as a result of global warming, experts said.

Wang Jinchang, a senior engineer with the Qinghai-Tibet Railway Company, said the track affected by soil erosion has almost doubled from 2003 to 2009.

About 443 kilometers of the rail are in areas being affected by desertification.

The railway was built across ravines, the Gobi Desert and permafrost.

An Fengjie, an official with China's State Forestry Administration, said the railway provided witness to the severity and scale of soil erosion on the Qinghai-Tibet Plateau.

Sands buried rail tracks and disrupted train services 1,362 times from its operation in 1984 to 2002 on the Xining-Golmud section of the railway.

Engineers set up barrier walls or simply lay big rocks along the tracks in affected areas to effectively prevent sands from encroaching on the tracks.

"But we still need to address the root problems of desertification," An said.

Global warming and over-grazing are blamed for the ecological deterioration.

Xinhua - Global Times