Coal is unloaded from freight wagons at the Datong-Qinhuangdao train operation section under China Railway Taiyuan Group in Datong, Shanxi province, on Wednesday. Shanxi, a key energy hub rich in both fossil and nonfossil resources, supplies stable coal to 24 provincial-level regions nationwide, while the Datong-Qinhuangdao line transports some 350 million metric tons of coal annually to power China's economic growth.