Link & Pin in general & on SVRy

The attached photo is of Sumpter Valley Railway #285 / #4 / #15 early in her career with the RR at the Oregon Lumber Company mill in Baker. While looking to see what kind of coupler was on the tender (looks kind of like a knuckle, but I can't still can't tell for sure with my bad eyes) I noticed what appears to be a link for a link and pin coupler hanging off the rear brake beam on the tender. Was that a handy spot to store an extra, or is that just part of the regular brake system? It looks to me like it is hanging loose on the beam, Is this a case of there being thousands of photographic examples of this practice if I had just paid attention? I have read that brakemen had to carry at least a spare link, but I can understand having places to hang an extra close at hand on cars and locos. Would explain why you can occasionally find intact links along the grades, they bounced off the hangers. BRIAN