Woody Guthrie Danville Girl https://www.youtube.com/watch?v=sd9Rf2ifDK4

There are several versions of this song. Words and tunes vary (it is "traditional"). The harmonies on the Guthrie recording make it sound very different from the way I learned the song, but I am am able to sing along with the tune I know.

I don't sing this tune, which is like a related song, "Waiting for a train": "Scott Everitt sings Danville Girl by [sic] Woody Guthrie"

The way Ry Cooder and Martin Simpson sing it is closer to the tune I learned Ry Cooder https://www.youtube.com/watch?v=WkJWHr5HWQQ
Martin Simpson https://www.youtube.com/watch?v=N8WRc8hyM88

There is also a recording on youtube of a Tyler Grant performing Good Morning Mr Railroad Man. And some others but those are the ones I've just sampled now.

I think I've found the version I heard way back then,: Cisco Houston

And I hope you are clearer about "What is going on". Choose whichever version of the song your like, even mix and match if you want to.