We've got a phone co. switching station in town we tour with the FD once a year or so.
It went from three floors of wire, relays, and loud humming to one floor (actually, about a medium office area of the floor about 20' x 30') with digital switching and fiber optic cabling. Still a few old realy boards, but not many.
The busswork in that building is incredible. All phone voltage (90 vdc IIRC), but the copper is about 1/4 x 3", and tied to old sotred acid batteries in glass in the basement.
