Interesting.....during my time on the D&S (1981-86), working on both the 497's return to service as well as operating and maintenance, I don't remember having to replace broken staybolts at the rate everyone seems to recall. With that said, yes, probably more than the 470's/480's but not in the multitudes described. They were replaced as needed, but not multiple ones per month. The CMO at the time I worked there would
never allow a locomotive to be sent out with multiple (more than 2 next to each other) broken staybolts and I
never encountered the steam in the cab as described by Earl.....and I fired the locomotive frequently. At this time, the FRA did not exercise regulatory authority over the D&S (that didn't happen until the mid 90's). However, the CMO continued to maintain the locomotives to minimum FRA (Part 230) standards. Yes, there were times we had to conduct overnight boiler washes and return the locomotive to service the very next day, but that was very infrequent when I worked there, maybe 1-2 times with the 497. In later years....I have no idea.
In the later Bradshaw years (late 80's early 90's), when there was a shake up in management, and the long time CMO was removed for a year or so, I do know that maintenance was deferred and all the locomotives suffered. If the appropriate attention wasn't paid to the 497, coupled with any poor firing practices, boiler treatment, etc., I could see that the worst descriptions of broken staybolts and leaking steam may have applied. If that was the case, these issues contributed to the broken staybolt problem as much as the design of the boiler did. I believe it was around this time that the locomotive was swapped with the C&TS.
My opinion, yes, the 497 broke more than its share of staybolts over the years, but there were other factors in play that may have contributed to this. As Earl points out, once the C&TS replaced the broken ones that were found, and the locomotive was again maintained to accepted practices and standards, the frequency of these broken bolts was minimized. Same as the years I worked on the locomotive in the early 80's.
MD Ramsey