Photo taken on June 15, 2019 shows the inside view of a train of the new airport subway line in Beijing, capital of China. Self-driving trains for the subway line connecting downtown Beijing with its new international airport started trial run Saturday, according to local authorities. Stretching 41.4 kilometers, the new line supports autopilot system and can run at a speed of 160 km per hour, with as many as 448 passengers, according to Beijing Major Projects Construction Headquarters Office. (Xinhua/Zhang Chenlin)