I have noticed in the AFE materials there are 3 predominant stands mentioned. The UP ones, some called a "High Banner" and a "High Seattle".
I think the location may be along the mainline South of the machine shop but just before the wood yard area. Maps of that area have the main and 2 or 3 sidings. You can see a hill to the left (West) and the cut bank on the right may be just shy of the drop off down to the river.
I think this photo is the same area. The switch stand would be one of the ones for one end or the other of these various sidings. Track maps also show a cross over between two of the track.