Yet another possibility:

Could the four verses of "Levee Song" be the original stanzas to which "I've Been Workin' on the Railroad" was the chorus?

That would make sense, as "Railroad" is just a little too brief to make up a good three-minute song.

Norm Cohen seems to imply this. In Long Steel Rail, 537-8, he writes: "In his compendium of American popular songs, Theodore Raph gives 1881 as the year 'I've Been Working on the Railroad' achieved widespread popularity, having been modified from an older song by black railroad workers. He cites 1900 as the date of first publication of 'Levee Song,' of which 'I've Been Working on the Railroad' was originally the second part."

But he then says there's no published evidence of "Railroad" prior to Carmina Princetonia in 1894. Cohen adds: "Of its assumed earlier existence in oral tradition among black laborers we know nothing."

All of which leaves "Levee Song" in limbo.

Bob