Steam trains cross an opencast coal mine at Sandaoling in Hami prefecture, Northwest China's Xinjiang Uygur autonomous region, Jan 13, 2016. Six steam trains are still used at Sandaoling, however, they will be gradually replaced by new electric engines this year. Three people - an engineer, an assistant engineer and a stoker - are needed to operate the trains. The designed speed is 70 km per hour, but they run at 20 km per hour, and the annual traffic volume is 8 million tons. [Photo/people.cn]