Thanks for the update Eric, I have not had the pleasure (?) of examining the 19's firebox. I do know that the 3's tubes are not welded. The way we run the 19 the firebox temps probibly do not vary that much but, as with all things, it is better to be on the safe side. I was helping Jerry once on the first fire up of the spring, and after we lit it off we discovered that the oil control valve handle was a quarter turn off. We had more fire than we knew what to do with; even the track was on fire. We pulled the oil shutoff as soon as we realized what was happening, but it could have been bad. Jim Gertz once told me that Polson/Rayoneer No. 70 was badly damaged by over firing a cold boiler.