"I've got a mule, her name is Sal, Fifteen miles on the Erie Canal." "Low bridge, everybody down, Low bridge, for we're going through a town...." About the long, slow trip along the Erie Canal -- and the mule the singer works with
The Erie Canal, as originally constructed, was a small, shallow channel which could only take barges. These vessels -- if such they could be called -- were normally hauled along by mules.
The Lomaxes, in _American Ballad and Folk Songs_, thoroughly mingled many texts of the Erie Canal songs (in fairness, some of this may have been the work of their informants -- but in any case the Lomaxes did not help the problem). One should check all the Erie Canal songs for related stanzas. - RBW