I'm recalling this off of old memories, but I was in Cuzco in summer 93 and I remember a couple of old Baldwins (I think) tucked away in a shed in the Cuzco rail facility on the route to Macchu Pichu. (3ft gauge as I recall)
I have a couple of very bad pictures floating around somewhere; early dawn, hand-held from a moving train...but sometimes bad pictures are better than no pictures.
No idea what engines they are/were, but if I can find the photos, I'll post them.
I only saw them as we were pulling out of the station...wish I had known they were there ahead of time - my pictures would have been better. Never had a chance to check them out again.