Police officer Zeng Renzhong (L) waves goodbye to a child on board a bullet train on the platform of the Longdongbao Railway Station in Guiyang, southwest China's Guizhou Province, Feb. 19, 2019. Zeng and Ye stuck to their posts during the Spring Festival travel rush on the platforms of the Longdongbao Railway Station, which was located 49 meters under the ground. (Xinhua/Ou Dongqu)