The construction of a major bridge over the Yarlung Zangbo River in southwest China's Tibet Autonomous Region completed closure on Saturday, which marks completion of the main structure of all 120 bridges in the 435-km railway linking regional capital Lhasa and Nyingchi. The 525.1-meter-long bridge at an altitude of 3,350 meters is the world's highest-altitude concrete-filled steel tube arch railway bridge. In early April, all the 47 tunnels on the railway were completed. Notably, 75 percent of the Lhasa-Nyingchi railway is bridges and tunnels, and it has a designed speed of 160 km per hour. It is expected to be completed and put into operation in 2021.