Staff members work on the construction site of Yarlung Zangbo River bridge of the Lhasa-Nyingchi section of the Sichuan-Tibet railway on a snowy day in Gonggar County of southwest China's Tibet Autonomous Region, Dec. 18, 2018. The 435.48-kilometer-long Lhasa-Nyingchi section of the Sichuan-Tibet railway is expected to be put into operation in 2021. (Xinhua/Wang Quanquan)