Most of the really early shots are from a distance and grainy so it can be hard to tell specs from actual dents or holes. This is the same switch stand at Beaver Brook from the same direction, but painted differently. It looks like at least some of the specs (like those in the upper-right) are similar in both sides of the stereo view, but it's hard to day for sure:

While looking at switch stand photos at Beaver Brook, I noticed how it appears that they added some retaining walls in the area, widening the creek channel. That put the switch stand precariously close to the edge. It looks like a tie extends out over the creek for the switchman to stand on (too bad this wasn't a stereo view). Same switch, different target though. Interesting footbridge. This was an R. M. Davis photo and he's listed as being active in Denver in 1887.

This is the same location with a different type of switch stand, but the retaining wall has been refined making the drop into the creek even more imposing. This is a W. H. Walker marked with "Idaho Springs", and he was listed as having a studio in Idaho Springs in 1891.

While looking through Clear Creek photos, I came across this one of a switch stand at Forks Creek. Again hard to tell, but it looks like some marks appear in both sides (such as the one at the 2 o'clock position of the lower circle). I also like the excursion car. This is a Weitfle view, so probably not later than 1885. It's not too early because the refreshment building is already complete.