The Detusche Bahn still runs DOS and Window 3.11 in their ICE I trains! They searched for admins 2 years ago. https://www.tomshardware.com/software/windows/ms-dos-and-win...
You should check out the NYC subway, which has electromechanical relays, cloth covered wiring, and pre-WW2 analogue panels.
They do not even have an OS!
i don’t want to say this explains things, but i do want to imply it