There was an interesting video posted by Danny Harmon (who goes by the handle of Distant Signal on YouTube).
He focuses on the increasingly rare small switching customer. Once upon a time it was the core of railroading. And while it is harder to find, in some places it can still be found as Danny presents in this video.
Enjoy the video! And if you like Danny’s videos as much as I love his voice then like the video and subscribe to his channel. I have no affiliation with Danny other than as a happy viewer of his content.