Couple nice shots there! I've been to steamtown in scranton PA and saw the 4012 on display outside there. You wouldn't think something with parts that heavy could move itself that easy. They are pretty impressive machines. I would have never guessed that they would restore one. Once in a lifetime chance to see it in operation.
It's interesting if you do a bit of research to see how big of a deal railroading was not that long ago. It was huge and just about every big factory anywhere was served by railroads. Where I live there were multiple main lines from five different railroads all converging in one area with two bridges crossing the Delaware river, both with double trackage. Several big rail yards, sidings to factory's, and several coaling facilities and workshops. Now there's only a single track mainline running through the area, with one other line still open for very limited use on occasion. A bunch of places where tracks used to be are grown over with vegetation and you wouldn't even know what used to be there.
Here's a pic (maybe 1940's?) entrance to a rail yard through a rock cut near me.
Same location now
Mightyraze did this photoshop on it for me awhile ago.