Children board a bullet train at the Yantai Railway Station in Yantai, east China's Shandong Province, June 30, 2018. China's summer transport peak period will begin on July 1, with a total of 647 million passenger trips expected to be made by train. The period runs from July 1 to August 31, when students on summer vacation have time to travel or return home. (Xinhua/Tang Ke)