A train travels along a bridge of the Qinghai-Tibet Railway above the Chumar River, a source of the Yangtze River, in Golmud, Northwest China's Qinghai Province, June 13, 2007. The landscape, lakes and the frozen earth on the Tibetan Plateau have been well preserved and the wildlife's migration remained unchanged since the world's highest railway was put to use, the State Environmental Protection Administration says in a survey report. [Xinhua]