The construction site of track-laying is seen inside a tunnel of the Lhasa-Nyingchi railway in Gonggar County of Shannan City, southwest China's Tibet Autonomous Region, March 8, 2019. The first 500-meter-long steel rail was successfully laid on the ballastless tracks of the Lhasa-Nyingchi Railway on Friday. The Lhasa-Nyingchi railway will help improve the railway network as well as transportation infrastructure along the railway, pushing forward the economic and social development in the region. (Xinhua/Chogo)