A couple of short history pieces on You Tube from one of my favorite channels,The History Guy, about trains. I love this guy's videos, lot of unknown history that is a lot of fun to watch.
Albany and Susqehanna Railroad:
https://www.youtube.com/watch?v=3AF_YJRlt1Y
The day they changed the track gauge (I know, lot of us know it, but still fun)
https://www.youtube.com/watch?v=4v81Gwu6BTE