It was kind-of inevitable that something like this would happen – SPOILER: as far as we know it only took out the timetables and ticketing, rather than the trains themselves. Good coverage, and plenty of links, here: https://www.thedrive.com/news/38897/adobe-flash-shutdown-halts-chinese-railroad-for-over-16-hours-before-pirated-copy-restores-ops

According to a report by Apple Daily, the problem reared its head for China Railway Shenyang in Dalian, Liaoning just after 8:00 a.m. on Tuesday, Jan. 12. Per an event timeline outlined by Github, the head of a switching station reported being unable to access the railroad’s timetables, which they normally did through a browser-based Flash interface. Over the next half hour, reports of similar failures poured in from across the network, with as many as 30 stations implicated according to a CR Shenyang statement reported by a Chinese blog.

https://www.thedrive.com/news/38897/adobe-flash-shutdown-halts-chinese-railroad-for-over-16-hours-before-pirated-copy-restores-ops