If you were a RR museum and were looking for a realiable switcher, with parts easy to find, to use on property (SW series or the like), where would you look these days? Are the class 1’s retiring many these days such that you might get a donation?
Look for a SW1001 or a SW1500 since they were among the last ones made. Use the 645 block so parts should not be to hard to get. If you get lucky might get one with Fleixcoils so smoother ride. Also look at the MP15 series also. Try CP or UP since they have the largerst Fleets I can think of.
There was an article in Trains within the last month or two about sales of used locomotives by UP, I think it was. All of them were big = 6-motor GEs, if I recall correctly. Even the ‘junkers’ went for a price of a couple thousand $ - with the scrap market as high as it is now, I doubt if there would be any ‘give-aways’.
New York City’s Metropolitan Transit Authority, recently retired the two Staten Island Railway’s two S-1 switchers, and you might contact them as to their disposition and availability of spare parts.