It does look like a dual guage track set-up. Not all of the inner tie plates are showing on the ties, but they could be between the ties, or thrown off to the side. Standard practice, on my old division anyway, was to throw all of the old plates and spikes out to the edge of the ballast, to be picked up later, to avoid them being thrown up onto the rails, or caught in a switch or frog. It may not have mattered on this old spur, though. Sometimes a dual guage section was put in for storage of old cars or engines, but this appears to be way out in the open, and not around any maintenance buildings, that we can see. I always see these things, too, and wonder why, when, and how. An old habit of comparing my work to others, and the reason behind it all. As for the stop, we used to use the old crossed tie method, as shown, and then dump a bucket of old ballast over it to hold in place, until a steel one could be built later in the shop, from old rails.