Good Morning Robin!
The 1472 day rule is a service day calculation. That is, fire in the firebox and pressure on the boiler. Days not in service are not counted so far as I know.
As for the 15 year apspect, That is the portion that says the tubes must be pulled every 15 years from the last time, in essence that the tubes were installed to do an internal inspection of the boiler. Thus, if a locomotive is rebuilt, and NEVER used,(the 1472 service day has no application) the tubes must still be pulled to do an internal inspection of the boiler and basically start all over again with the Form 4 calculation etc.
There are several ways of looking at this. If the locomotive is fully restored and not used, and yet is stored in an enviroment that fully protects the equipment, then pulling the tubes to do the internal is a very expensive and unnecessary exercise. On the other hand, if the locomotive is stored in an enviroment that is corrosive, wet, exposed to the elements and otherwise generally uncared for, then the concept of pulling the tubes, though never used makes some sense. What the rule also does not take into account is that pulling the tubes in and of itself is not the only way to do an internal inspection, especially on a very small boiler. There are other methods that are equally effective such as using borescopes, UT testing, and a bunch of others that can accomplish the same thing.
Naturally, there will always come a time when the tubes must come out. The question is, I suppose, should that arbitrarily be determined by the calendar,or condition, or something else. The rule does not require the tubes to come out because there is something inherently wrong with them at the end of 15 years, it requires them to come out to do the inspection. As far as I know, the same tubes can be safe ended and put back into the boiler again. But then, the otherwise perfectly new tubes will have been cut and welded back together. Personally, I prefer tubes that have not been cut, welded and stuffed back into the boiler.
What makes this all the more interesting is that the State boiler inspectors have no such calendar requirement. They look at the condition of the tubes, and the condition of the boiler shell as determined by their inspection methods. That is why Eureka has a current operating certificate from the State of Nevada. Both agencies are deeply concerned with the condition and safety of the boiler. But who is right? Maybe they are both right, and the FRA rule needs a little tweeking. I guess one of these days we will find out.
Thanks for your interest.
Dan
