A woman demonstrates how to scan a QR code at the platform gate of a local train station.

Starting from Tuesday, passengers on three railway lines in the Yangtze River Delta region can board trains by simply scanning a QR code, the China Railway Shanghai Group announced on Monday.

QR codes exempting passengers from obtaining physical tickets will be trialed on the Shanghai-Nanjing intercity railway, the Nanjing-Anqing high-speed railway, and the Nanjing-Qidong railway, covering 14 cities in the region in total.

The codes rely on e-cards which can be obtained by registration on the mobile app 12306, the country's official online railway ticket-booking platform, the group said.

Invoices can be printed at ticket vending machines at railway stations within 31 days of rides, it said.

The codes require real-name registration and can only be used by the registered person, the group said.