When I first heard "Longest Train" back in 1960, I think, the verses were a tad different, but I do not know whose (aside from my banjo-player) they were:

"The longest Train I ever did see
Was a hundred coaches long.
And the only woman I ever did love
Was on that train and gone.

On that train and gone, love,
On that train and gone,
Only woman I ever did love,
Was on that train and gone.

The train pulled out, and the whistle blew
With a long and a lonesome sound
She is gone, she is gone,
ANd left me here alone.

This version also wandered over into a number of versions from the "Who's Gonnas Shoe Your Pretty Little Foot" archetype. So I suspect it was a hodgepdoge sort of thing.   

A