A staff member checks the wheel of a freight train of China Railway (CR) Express from the city of Chongqing to European countries before its departure in Shapingba District of Chongqing, southwest China, Aug. 29, 2018. Each freight train of the CR Express on the west Chongqing section would be checked before departure by the checking unit to eliminate all kinds of faults and hidden dangers. The checking unit consists of 74 staff members, and it has completed 1,936 checking missions on CR Express freight trains. (Xinhua/Tang Yi)