An elderly citizen uses the ticket vending machine to buy a ticket at the Shenzhen Airport Railway Station along the Guangzhou-Shenzhen Intercity Railway in Shenzhen, south China's Guangdong Province, Dec. 15, 2019. The Guangzhou-Shenzhen Intercity Railway designed with a speed of 140 km per hour started its official operation on Sunday. A total of 15 stations are set along the railway, which has joined Guangzhou, Dongguan and Shenzhen into a "one-hour economic circle". (Xinhua/Liang Xu)