It's a haunting song. I've always heard that first verse as:

The faces in the photograph are faded.
I can't believe he looked so much like me,
For it's been ten long years today since he left for old Cork Station -
Saying "I won't be back till the droving's done."

The variations are in italics. I'm not saying that was how it was sung, just that that's how I've always heard it in my head, and how I'd sing it. That's the folk process.

They are minimal changes, but they alter the story. I'd read it as looking in the first verse at a photograph of the father who'd left many years ago. (Or maybe a grandfather or farther back even.) And then moving into the voice of the driver far away.