It seems there are basically three choices here.
1.) Keep on fixing 'em, which will at some time include building new boilers, tenders, cabs and perhaps even frames. The advantage here is, the incremental cost is held down, as you are esentially buying a new locomotive on the installment plan. With proper budgeting and management, it is possible to gradually get ahead of the game using this plan. Sounds like the C&TS is taking the first steps in that direction with the #497.
2.) Buying a used engine from where ever. This choice is probably not very viable. The suggestion of Cuba and the Phillipines is out, as there are not any 3ft. gauge engines left that are even close to being big enough for the C&TS. Also, the engines they do have are so worn out as to require step 1 as well.
Mexican 3 ft gauge engines on display are small, plus you will never get the Mexican's to part with them. Their cultural heritage laws make it impossible to repatriate steam. Many have tried, all have failed. Central America has some 2-8-2's that might be close to a K-27, but they will also be difficult to buy and not big enough for the needs of the C&TS.
Columbia has some 4-8-2's which are possibly big enough, but several parties have tried to buy them over the years and have also failed. They are probably worn out and stripped of all useful fittings as well, by this point.
There are some big meter gauge engines in Brazil and Argentina, but now you are into serious rebuilding, although the idea of a 2-10-2 or 2-10-4 does have a certain appeal!
3.) Building new engines. I don't know if it was Coke or Earl that coined the phrase, "cubic money," but you'll need it for new construction. Until American railfans start acting more like their cousins in the UK (ie, willing to pay for stuff), then option #1 is our only choice.
