Rich,
In the last 2 years, I was lucky to be able to snag 2 collections, one of 400+ pictures and another one with 200+ done by a a Reading Railroad employee. The 200+ pictures were in an album that has the pages literally falling apart, but the pictures are fine. All are of a 1950's Pennsy, 90% steam, lots of the B-6 switchers and some A-5 switchers. Ocassionally, there will be a nice single image, like this one that I could not pass up.
So, these collections come up from time to time. They are worth looking out for.
Tom