Using surplus, off-peak subway capacity for express deliveries

BEIJING — On a typical weekday in December, away from the rush hour crowds, a batch of aviation-related documents was loaded into the luggage compartment of the Beijing Daxing Airport subway line. In the passenger cabin ahead, a few commuters sat quietly, scrolling through their phones.

The Daxing Airport subway line, China's fastest urban subway system, runs at a top speed of 160 kilometers per hour. It connects Caoqiao Station in downtown Beijing to Beijing Daxing International Airport in the southern suburbs, covering 41 km in less than 20 minutes.

"If we use road transportation, the journey could take at least 40 minutes, not to mention delays caused by traffic congestion or bad weather," said Qu Lili, a project manager at JD Logistics in Beijing.