A crew member checks a carriage of a train for the new airport line in Beijing, capital of China, Jan 29, 2019. The 160-kph new airport line, linking south Beijing to the city's upcoming new airport in Daxing district, is the fastest intra-city rail transit in China. The line is scheduled to start test operation with the launch of the Daxing International Airport in this September. [Photo/Xinhua]

A crew member checks seats in a carriage of a train for the new airport line in Beijing, capital of China, Jan 29, 2019. [Photo/Xinhua]

A crew member checks a carriage of a train for the new airport line in Beijing, capital of China, Jan 29, 2019. [Photo/Xinhua]

The photo shows a train for the new airport line in Beijing, capital of China, Jan 29, 2019. [Photo/Xinhua]