MYSTERY SOLVED: I THINK
Good morning Mr. Elliott, I found another picture of Downie Bros. on the same lot. Note in the top picture , as before the men to the right sewing canvas, now look at the bottom picture at the same men, this time to the left. Also on the right of that picture is a portion of the big top, obviously, the 3 pole top is the sideshow. This whole thing seems to be during set up.