I can attest to Stewart's claim that jacking the drivers up into the frame is a lot easier than lowering the frame. The last engine I helped re-wheel was a Pacific (4-6-2) with 80-inch drivers. The boiler and frame were lowered onto the wheels and driving boxes by a 200-ton overhead crane, and it was a scary, scary operation. We had to hold the boxes in alignment in the frame as the boiler and frame came down. I would have preferred a drop table and pit, but there wasn't one available.