A worker from China Railway No. 2 Engineering Group is seen on the track laying scene at the Ban Nong Khay Tunnel, in Vientiane Province, some 60 km to the north of capital Vientiane, Laos, on May 23, 2020. As each row of 14 cement sleepers laid smoothly across the Ban Nong Khay Tunnel at the prescribed distance and then the 500-meter long tracks settled on the sleepers precisely by the engineering train, China-Laos Railway's tracks has passed its first tunnel on Saturday.  [Photo/Xinhua]