It then reverts to the augmented dominant of the minor key in the word `` time '' in the line `` Once I built a railroad , made it run \ / Made it race against time , '' marking the end of prosperous times , and changing to a wistful mood .
It then reverts to a minor key in the word `` time '' in the line `` Once I built a railroad , made it run \ / Made it race against time , '' marking the end of prosperous times , and changing to a wistful mood .