I enjoy the thread below about re-boilering a loco. This is more than likely going to be more and more common as time goes along, so I feel it is a good thing to discuss. So here are my boiler questions.What kind of problems arise when a operator/owner decides to put a new boiler on? Many older boilers need to be re-engineered for safety factor of 4, so does the new boiler need to be approved by Washington {FRA}? Are they thorough in checking out the new design? I know Texas State RR has had a couple of them built, did they have any problems getting from the "design to the frame"? Or anybody else for that matter?It was mentioned below about modifying a lap seam boiler. I also remember someone contributing a nice couple of drawings of original seam, modified and the standard seam with backing plate. Is this a hard repair/re-engineering job to get ok'd by Washington? I have always wondered why one couldn't alter the original lap seam to a more strong design, but have not heard much about anybody actually doing it. I know in Wi the state regs do not allow for a large barreled lap seam barrel, or they used to not allow them. I don't recall where the FRA is with them. After reading about them letting go, I think I would feel safer with a modified seam myself.I hope I was able to ask these questions somewhat intelligently, I have had a long day. THanks in advance, John Risley.