Chris and Richie were very careful to measure each and every patch, dent and wrinkle on the original to duplicate it as best we could. We even left out the bolts/.rivdets in the upper coal doors as per the original. One of the more difficult challenges was to ensure that we were only replicating pre-museum work which often times overlapped original patches. While the later work was all welded, there were some curious anomolies, one of which was an internal riveted patch. It appears as a seemingly unnecessary row of rivets on the exterior of the shell. Upon examination we discovered the remains of an internal patch. So if someone asks why there is a short horizontal row of rivets and no visible patch - that is the reason.