Sheila, I know the song as "The Levee Song" (also called, "I've been workin' on the levee") First verse goes
I
When I lived down in Mobile town, Workin' on the levee.
All day long roll cotton down, workin' on the levee.
II
But now, I'm workin' on the Railroad,
All the livelong day. etc. etc. etc.

Following is a quote from, "Gonna Sing My Head Off", "American Folk songs for Children" by Kathleen Krull.
" "This Sturdy anthem of the railroad workers may have descended from an old Irish Hymn or "I've been working on the Levee" sung by gangs building levees on the Mississippi River. Dinah was perhaps, a train or , perhaps, a real woman, with "Blow Your Horn" meaning "call me for lunch"
I've looked through about a quarter of my reference music books and can't find it atributed to any one person. I don't know whether or not to accept Ms Krull's assumptions. She doesn't include the first verse, and, My assumptioni, given the accent, would be that Dinah is , "Diner" (dini ng car etc.) Anyone can take a guess at this one.
Did you ever see Tim Conway dressed in a Nazi Uniform with a "Hitler" ventriloquist dummy, torturing an American POW by singing one verse at a time with long pauses in between. You kept thinking that the song was over, when this high pitched german hysterical, but muffled voice came in with another verse. sThis was on the "Carol Burnett TV Show" years and years ago. I'm laughing now just thinking about it. I knew the song, but still kept hoping and thinking that it was over.
Who the hELL KNOWS WHERE IST CAME FROM . My guess would be (if it were a "written Song") Henry Clay Work or Steven Foster would be my prime suspects