As a non-local, when I hear "tube" I think toothpaste, swimming and repairing tire punctures. Mass transit may not even be in my top 5 - and that's fine.

Human language ambiguity and locals have their shibboleths - we don't have to optimize for tourists.

Swimming?

Another shibboleth: donut-shaped inflatable pool floaties are called "inner tubes" 'round here.

Oh! To be honest I'm not actually sure what we call those ('pool inflatables' is all I can think of, somewhat generic) but I don't think it's tubes/inner tubes.