Do you actually mean that? What you’ve said doesn’t seem to make a lot of sense to me; I’m wondering if maybe there’s some translation thing going on here.

https://wiki.openstreetmap.org/wiki/Key:access and https://wiki.openstreetmap.org/wiki/Key:tourist_bus say vaguely sensible things (apart from the “which can be understood to be synonymous to a coach” bit).

Some “tourist buses” may be “coaches” (in either vehicle type, or itinerary, or both), but some are not.