I can't help but make a general comment on this subject. Within our industry there are good contractors, bad contractors, and ignorant contractors.
The good contractors usually are the most expensive because they do their homework and try their very best to ensure that a quality job is done, or they don't do the job at all. They often are not chosen to do the work because there is always someone who will do it cheaper, and too often price carries the day.
When price wins out, you usually get the bad or the ignorant contractors who will knowingly cut critical corners or unwittingly, because of lack of knowledge, cut those corners. Because of their construction, steam locomotives can be very forgiving to a point, and will often at least function on some level with lots of defects. They usually will not run very long that way, and often damage themselves further, or in some cases fail in a big way.
After 39 years working on these beasts, I have some level of confidence with them, however they still humble me more frequently than I'd like to admit. Steam locomotives break down - they always have. Trying to cover every base on a rebuild lessens the probability of a breakdown and usually all but eliminates the possibility of a catastrophic failure, but it is not a guarantee of trouble free operation. Covering all the bases takes time and money. Compensating highly qualified and competent people costs money - and it should. Steam will not survive on minimum wage. Sure, there are very talented and knowledgable volunteers out there, and they are doing some wonderful things, but learning about and working with steam locomotives is a full time job that requires intelligence, dedication, expertise, experience, and practice, practice, practice. The next time you need brain surgury, do you want the person who has been in the brain surgury hobby on weekends for thirty years because he can give you a better price, or will you opt for the doctor who has been doing it daily for the last thirty years? Hours in the saddle means something, and it comes with a cost.
This post only addresses mechanical issues. All the same things can be said regarding operators. The Good, the Bad, and the Ugly - but that is another topic - and with a tip of the sombrero to the legendary serape, I'll leave that subject for another day.
In the end you get what you pay for. Pay now or pay later - with interest. I often wonder how often we need to see this sort of thing happen before that reality sinks in.