Milestones in China's high-speed railway development

Crew members of a bullet train which is to operate on the Xi'an-Chengdu High-Speed Railway, pose for pictures in front of the bullet train in Chengdu, capital of southwest China's Sichuan Province, Dec. 4, 2017. High-speed trains linking Xi'an, capital of Shaanxi Province, and Chengdu of Sichuan, began operation on Dec. 6. (Xinhua/Xue Yubin)