Starting from December 7th, 2022, train passengers buying train tickets, entering and leaving railway stations will no longer need to show a negative 48-hour COVID-19 test result and health code, according to the latest announcement by China State Railway Group.

Also, no more peremptory landing inspections now. Passengers entering Beijing do not need to provide Beijing Health QR code now.

Further reading:
Top Things You Should Know before Taking the Train in China Currently