A train runs at the foot of snow-covered mountains in northwest China's Qinghai Province, Oct. 24, 2009. The Qinghai-Tibet railway will enter its 4th winter operation after three year's safety running, which strongly boosted the economic and social developments in Qinghai and Tibet Autonomous Region.

A train runs in the frozen earth area in Kunlun Mountain of northwest China's Qinghai Province, Oct. 24, 2009.

A train runs near kiangs (Tibetan wild dunkeys) in northwest China's Qinghai Province, Oct. 24, 2009.