The entrance to Zhongtiao Mountain Tunnel is pictured in Shanxi province, Jan 29. [Photo/Xinhua]

Workers of China Railway Tunnel Group pose for a photograph at a ceremony marking the connection of both sides of Zhongtiao Mountain Tunnel in Shanxi province, Jan 30. The tunnel is a key part of the Inner Mongolia-Jiangxi Railway, a major domestic coal transportation line stretching more than 1,800 kilometers and scheduled to begin operations in 2020. [Photo/Xinhua]