Aerial photo taken on April 29, 2019 shows the box girder installation site of Chengjiang bridge on the Guiyang-Nanning high-speed railway in Du'an, south China's Guangxi Zhuang Autonomous Region. With a total length of 512 kilometers, of which 482 kilometers is newly constructed, the railway line will cut travel time from Nanning to Guiyang from over 10 hours to 2 and half hours. With a designed maximum speed of 350 kilometers per hour, the line is expected to go into service in 2023. (Xinhua/Lu Boan)