I sing the following (the words have probably changed slightly due to the folk process and my memory):

Come all ye gallant drivers, wherever you may be.
Whether you drive a Euclid or a fifty-four RB.
Keep your hands upon the levers, cut and fill a steady load.
Well you're going nice and steady lad, a ploughing of the road.

Oh we've built a hundred airfields through the snow and wind and rain.
Built atomic power staions, more dams than I can name.
We've cut through rock and swampland, moved mountains by the load.
Well you're going nice steady lad, a ploughing of the road.

When your digging days are over, and you've shifted your last ton.
When your "Cat" gets broken up for scrap and your RB ten won't run.
When you've had your last stamp on your cards, and you've reached you last abode.
There will still be many people travelling up and down your road.

Nb "Cat" (Caterpillar) and RBs are types of mechanical diggers.

I also first heard the song sung by Bob on the Newport recording.