In this aerial photo taken on June 23, 2018, workers construct a bridge in the Gansu-Ningxia section of the Yinchuan-Xi'an high-speed railway in northwest China's Ningxia Hui Autonomous Region. The 617-kilometer high-speed railway is scheduled to start operation by the end of 2020 with a design speed of 250 kilometers per hour. (Xinhua/Hou Dongtao)