A worker checks the precast beams for the Yinchuan-Xi'an high-speed railway in northwest China's Ningxia Hui Autonomous Region, April 17, 2017. The 618-km high-speed railway, which links Yinchuan, capital of Ningxia, and Xi'an, capital of southwest China's Shaanxi Province, is expected to open in 2020. (Xinhua/Wang Peng)
