I would really like to compliment the team that assembled the bridge.
When I was helping Rick Sisson decide where to cut the rails, we set a stake and marked one main beam corner, then rotated to the other main beam to check it, finally rotating the whole bridge 180 degrees to check both beams on the other end. Relative to the mark on the stake, the other three beam corners were within the width of the line on the stake.
This is nearly unbelievable accuracy. The structure is amazingly square and the pivot is perfectly centered.