Well, I finally got back to the spot with my buddy today to take a first-hand look at this thing.
First, I don't think it's a valve. The reverse side of this very heavy object has tracks cast into it that would allow it to be mounted on and slide along two rails. The round, tubular portions look like cylinders that may have contained pistons. On one end the cylinder is open and has an opening about two inches in diameter. The other end is closed except for a 3/4" diameter hole. The center piece between the two cylinders looks like it would allow rotation but I don't think being mounted on rails would allow that to occur. A 1" diameter shaft protrudes for one side of the object.
My theory is it was a part that was replaced on a piece of heavy equipment (logging possibly)) and simply left behind.
We did not bring it out as the walk in is rough and this thing probably weighs 30-40 lbs.
Let the guessing continue !