Lead Belly recorded I think seven versions of Rock Island Line, including fragmentary ones. He was probably with the Lomaxes, as he acted as their driver and guide, when they recorded convicts singing this song in 1934 and may have learned it then as it didn't feature in his repetoir before that. His intros vary: at first he just describes how it was used as an axe cutting song and then he develops the story of the 'engineer' fooling the 'dept agent'. One version is with the Golden Gate Quartet and with no introduction, reviving the original idea of the song.
Lonnie Donegan, lifting popular music from 'ballads' and novelty songs, recorded it at least twice.
I'd like to know if in fact livestock really didn't attract a toll on American rail roads at this time.