Update:
This should be the last update on Emmett. Kid-zilla and I were “all in” on Sunday to get his circus engine running.
First, we gathered the two derelicts, ex-Other Emmett and ex-North Star (not be confused with our North Star of recurring LSC fame, who is very much in service!) to have them on hand as parts donors. ex-North Star, as described above, is already slated for repair; ex-Other Emmett, which is actually in better shape, will follow AFTER we figure out what we are doing!
Then, we removed Emmett’s boiler and cab from the chassis. We discovered that the after drivers had plungers, too, which were frozen solid and had cracked housings.
This consigned it to the parts bin, but not before we removed the motor and gear block and carefully labeled the wires.
Interestingly, the lower plate of the chassis had the castings to receive those brass busses that transfer power on later models, suggesting that this was a bit of a “transition” model with parts from multiple generations. Neat. Not helpful, but neat.
Both derelicts had equally stuck plungers, so we set them aside. We had originally planed to simply mount Emmett’s wheelset into a donor chassis, but we discovered that a.) “he” had a totally different gear box, and b.) “his” wheels lacked the brass collars that take power from the wheel and transfer it to the busses.
Schimpf! 
That meant we were going to have to try to move wheels and axels and things, but, lo! I remembered that @PeterT had show the path to us before, so I referenced Bachmann 4-6-0 Periodically Stops and Whines, and re-discovered that we could simply removed the plastic wheel coverings from the wheels themselves! I began the process, and, having broken every plastic plug from Emmett’s rods, left that to Kid-zilla. He salvaged the survivors from Emmett’s old chassis and scrounged the rest from the bits box. Show off!
We got all the wheelsets in place, then we reinforced the screw stems with zip ties and CA glue as we had learned to do earlier in this thread.
Next, it was off to the test stand…
…but only after a brief lecture from Kid-zilla about the importance of testing as you go. We paid careful attention to quartering as we installed the rods (Kid-zilla found and cleaned spare pushrod to replave the broken one on Emmett), tested again, and then proceeded to final assembly.
Emmett took one more trip on the test stands before “his” final test, a return to service.
Video: “Emmett’s” Final Test
Kid-zilla is over the moon. I have no idea how many trips Emmett will make before Bachmman quality leads to his shredded gears and embrittled plastic, but, for now, the circus rides the rails on the island of No’u’ea!
Thanks to all who gave advice, parts, and encouragement to get this train moving!
Eric
