A passenger takes photos on a bullet train running on the Jinan-Qingdao high-speed railway during its test run in east China's Shandong Province on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)

Passengers wait to get on a bullet train of Jinan-Qingdao high-speed railway during its test run at Zouping Railway Station in east China's Shandong Province, on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)

Passengers wait to get on a bullet train of Jinan-Qingdao high-speed railway during its test run at the Hongdao Station in Qingdao, east China's Shandong Province, on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)

A passenger takes photos on a bullet train running on the Jinan-Qingdao high-speed railway during its test run in east China's Shandong Province on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)

A passenger takes photos on a bullet train running on the Jinan-Qingdao high-speed railway during its test run in east China's Shandong Province on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)

Passengers wait to get on a bullet train of Jinan-Qingdao high-speed railway during its test run at Jinandong Railway Station in Jinan, capital of east China's Shandong Province, on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)

A train attendant talks with passengers on a bullet train running on the Jinan-Qingdao high-speed railway during its test run in east China's Shandong Province on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)

A passenger takes photos on a bullet train running on the Jinan-Qingdao high-speed railway during its test run in east China's Shandong Province on Dec. 17, 2018. The 307.9-kilometer Jinan-Qingdao high-speed railway is expected to be put into service at the end of this year. (Xinhua/Dong Naide)