Looks like an old American No. 2; I spent a lot of days off-bearing on one of those that we bought in the late 50's and rebuilt in steel. The off-bearer is the man in the foreground, he puts the slabs on the slab pile and stacks the cants. Our mill was powered by a Gray-Marine 6-71 converted to radiator cooling and had a 8 foot piece of 4" pipe straight up off the exhaust manifold, no muffler, you could hear that engine a mile away, or more, every time the saw bit wood. I think the negative has been reversed on this photo; the sawyer, the man on the other side of the saw, pulling the carriage drive lever should have the saw on his right.