I remember the track south of Hermosa in the early 1970's. It would slam you from side to side on mumerous occasions. And, after being on the train most of the day, that was a little tiresome.
I never will forget the the first time I rode the C&TS and didn't realize for a while that we were NOT getting bounced around from Lava to Antonito. It came as a very pleasant surprise. I think that was the first part of the track that got lots of ballast and great alignment. It really made a enjoyable ride out of it. Of course most of the track is that way now.