If you have an industry large enough to need a plant switcher, put it there. Even if it's just parked on a modern layout, it could represent "corporate history", with the industry having bought it second-hand. A lot of plants own their own Trackmobiles, and this is nothing but a primitive version of one, without the flanged wheels.
I once saw a farm tractor with couplers used to switch a grain elevator, which, again, is the same idea. I'm sure you can find someplace that has, or had, a use for it.