Well after some research it appears this isn't a particularly rare or valuable tool, maybe worth $20? They seem to have made a gazillion of these, and since it's often referred to as a "railroad wrench", the B&O provenance doesn't mean much either. Still cool though, happy I picked it up
Another question though, interesting that the nut to adjust the jaws is a hex instead of round/knurled. Was this so another wrench could be used to get an extra tight grip on the nut that was trying to be tightened/loosened, or was it just cheaper to manufacture that way?
