The actual infra-backend of the swiss Teletext is quite cute, just a single, Windows 2000 (if I remember correctly, maybe Server-edition) PC, running in a Datacenter-rack, on the floor of course, with about one dude who knows how it all works. Not sure how other countries do it, probably with similar, archaic setups.

At least that was the state about 10 years ago, maybe they upgraded the infra since then.