To add to N&W 1218 comment on sounds. I believe the article was in the LCCA Lion Roars.
I will look through my files to try to find it.
I remember it discussed how the Lionel sound engineers recorded the real J. They specifically mentioned the whistle echoing off the hills (I think in Ohio).
Neil Young was inspired by a photo he had seen of an older J pulling a freight. Also, Neil was very interested in capturing real sounds for Railsounds.
He definitely accomplished it with the warhorse J sounds.
I have the paper copy around here.