So I was researching how one calls an underground rail system in a city in English.
It turns out it depends on which city it is. The consensus seems to be that anything outside of the US and UK is a "metro". But ours in Saint Petersburg has a bit of an identity crisis. It does call itself that on its English website, but I've also seen signs that say "subway entrance".
Also I'm still not sure what one calls the German "U-Bahn"s. English as a foreign language is weird sometimes.
@grishka it's the Buffalo Metro here 😂 (USA)