My father once told me that a lot of machine shops used to be set up that way, except that the powered shaft ran along the ceiling instead of in a floor trench. "Just throw a belt up over the shaft" and attach it to the machine you want to use, was how he described it.
I don't know if it's still there, but there used to be a fancy restaurant in the Eastlake part of Seattle that had started out that way, and still had the old Art Deco-ish drive shaft running around the ceiling. It was a neat touch point when I saw it and remembered my dad's description from years before.
My understanding is that this paradigm was incredibly dangerous, with a lot of workers losing hands and arms in accidents. Turning on or off a given machine involved physically putting the belt on or pulling it off, and you could easily get caught in it. A very clever system for the technology of the day, but it's good we don't use it anymore, at least without more advanced safety mechanisms and practices.
I would have assumed they would have clutches so that individual machines could be disengaged. The large open belts running up to the drive shaft on the ceiling were dangerous regardless.
I don't know if it's still there, but there used to be a fancy restaurant in the Eastlake part of Seattle that had started out that way, and still had the old Art Deco-ish drive shaft running around the ceiling. It was a neat touch point when I saw it and remembered my dad's description from years before.