24-hour transit: every open port, all nationalities
The National Immigration Administration states that all open exit-entry ports in China run the 24-hour transit policy for nationals of every country. If you transit through China to a third country or region you may stay up to 24 hours without a visa, provided you hold valid travel documents and onward tickets with confirmed seats and do not leave the port's restricted area. That covers a land or rail port as much as an airport.
Source: National Immigration Administration, P.R.C. (en.nia.gov.cn) — Visa-Free Transit Policies (policy interpretation) (source policy-interpretation page (eligible-ports table on the page is an image); read August 8, 2026)