There are tons of versions of this song. In the Library of Congress on-line archive, a railroad worker says they changed the verses almost every time they sang it.

When John Henry was a little baby
no bigger than the palm of your hand,
His Mamma looked at John Henry and said,
Johnny be a steel drivin’ man;
lawd, lawd.
Johnny be a steel drivin man."

Peabody bought a steam hammer,
said, "A man ain't nothin but a man.
You’ll never beat this machine of mine.
Don’t need you or those hammers in your hands;
lawd, lawd.
Don’t need you or those hammers in your hands."

John Henry said, “Mr. Peabody,
a main ain't nothin’ but a man.
But before that steam hammer beat me down
I'll die with my hammer in my hand;
lawd, lawd,
I'll die with my hammer in my hand.”

John Henry drove steel 'round that mountain.
Shook so hard Peabody cried, "It's was cavin’ in."
“A man ain’t nothin’ but a man Peabody.
And that ain’t nothin’ but my hammer suckin’ wind,
lawd, lawd,
ain't nothin' but my hammer suckin' wind.”

John Henry hammered up that mountain,
called to his wife, who’d come to see,
“I'm up so high I can touch the sky
but it’s gonna be the death of me,
lawd, lawd,
it’s gonna be the death of me.”

Mr. Peabody came to measure,
couldn’t believe his eyes.
John Henry laid down 12 feet of cold hard track.
They tell me that steam hammer laid 5.
Lawd, lawd,
they tell me that steam hammer laid 5.

John Henry died that evening.
left his pretty Polly Ann.
Buried him where he hears trains go rumblin’ by.
They say yonder lies a steel drivin’ man;
lawd, lawd,
yonder lies a steel drivin’ man.