A box girder is installed on the Rugao section of the Yancheng-Nantong high speed railway in Rugao, a county-level city in Nantong, East China's Jiangsu province, on Dec 30, 2018. The new girder is also the first one installed on the line, which is expected to boost Rugao's economy. The installation of girders is expected to be completed by September 2019. [Photo/cpcrugao.cn]