I remember this from the late 60s, we sang it at school in a combination class of history and music. I recall the words slightly differently, but then I was only 9 and it was a long time ago! :

"Come all you poor people in old cotton rags,
for there's work to be done now across the peat crags,
A road we must build now on old Feather Bed
A road we must build now or soon we'll be dead"

Sing each syllable and 'punch' each word to a steady beat, repeat each time getting slightly faster, you will get a gist of the tune.