Subway drivers control a train of the northern extension of Beijing Subway Fangshan Line during a trial operation in Beijing, capital of China, Sept. 20, 2020. The middle section of Beijing Subway Line 16 and the northern extension of Beijing Subway Fangshan Line have carried out trial operations on Sunday. Upon their official start of services, the two subway routes will help improve traffic in the capital city's northwestern and southern regions. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 20, 2020 shows a train car of the northern extension of Beijing Subway Fangshan Line during a trial operation in Beijing, capital of China. The middle section of Beijing Subway Line 16 and the northern extension of Beijing Subway Fangshan Line have carried out trial operations on Sunday. Upon their official start of services, the two subway routes will help improve traffic in the capital city's northwestern and southern regions. (Xinhua/Zhang Chenlin)

A staff member examines a train car of the middle section of Beijing Subway Line 16 during a trial operation in Beijing, capital of China, Sept. 20, 2020. The middle section of Beijing Subway Line 16 and the northern extension of Beijing Subway Fangshan Line have carried out trial operations on Sunday. Upon their official start of services, the two subway routes will help improve traffic in the capital city's northwestern and southern regions. (Xinhua/Zhang Chenlin)

A staff member examines a train car of the middle section of Beijing Subway Line 16 during a trial operation in Beijing, capital of China, Sept. 20, 2020. The middle section of Beijing Subway Line 16 and the northern extension of Beijing Subway Fangshan Line have carried out trial operations on Sunday. Upon their official start of services, the two subway routes will help improve traffic in the capital city's northwestern and southern regions. (Xinhua/Zhang Chenlin)

Photo taken on Sept. 20, 2020 shows a train car of the middle section of Beijing Subway Line 16 during a trial operation in Beijing, capital of China. The middle section of Beijing Subway Line 16 and the northern extension of Beijing Subway Fangshan Line have carried out trial operations on Sunday. Upon their official start of services, the two subway routes will help improve traffic in the capital city's northwestern and southern regions. (Xinhua/Zhang Chenlin)