Re: Returning 476 to Service

"There was also some discussion about 476 being different from the other active D&S locomotives because it was not in service and no extensions had been filed when the new FRA rules went into effect."
None of those distinctions matter any more.
In steam days, boiler had to be inspected every 48 months, with one possible extension to 60 months. In 1978, the notion of "out of service credit" was added to the rules, and if you didn't fire up a locomotive for a calendar month, but kept the paperwork current, it didn't count in your 48 months. Multiple flue extensions started popping up, too.
Also, the way the rules were worded, it was ambiguous whether the ORIGINAL Form 4 could be filed, or an UPDATED Form 4 had to be calculated.
The net result of these two changes was that boilers weren't getting inspected as often, and the Form 4 might not match the actual condition of the boiler.
Now, operators are required to calculate and file a new Form 4 for every 1472 day inspection. No ifs, ands, or buts. There are no flue extensions under the new rules, and the last flue extensions under the old rules were granted in 2001, and expired in 2002.
So any steam locomotive operating today under FRA rules has had a full Form 4 done on it, or will before it operates.
There would have to be a pretty nasty problem unique to 476 to require a new boiler. If there are any quirks to the K28 boiler, they aren't enough to keep 473 and 478 out of service.
JAC