Ever heard of industrial musicals? Don’t worry, neither has the majority of the human population — largely because no one was intended to experience these well-funded, professionally-made productions from the ‘50s and ‘60s about corporate life beyond the people who created them and the employees they were meant to inspire.

Longtime editor Dava Whisenant’s debut documentary Bathtubs Over Broadway explores this lost world via comedy writer Steve Young, her former colleague on “The Late Show with David Letterman,” whose search for oddball vinyl to use in the program’s “Dave’s Record Collection” segments led him to these unusual yet endearing song collections.

What Young found was a trove of entertaining alternatives to traditional motivational or informative speeches that were also a well-paying means of employing up-and-coming talent, including Florence Henderson, Chita Rivera, Martin Short, and the team behind Fiddler on the Roof.

Whisenant presents Young’s bizarre journey with industrial musicals in an engaging, entertaining manner, though the film grows somewhat repetitive as he hunts down and listens to records, amplifying the esoteric nature of his passion.

Watching Young and others geek out over something that still feels foreign is part shortcoming on the storytelling front and also a sign of the material’s inherent limitations, but the connections he makes with performers who are still living and the mutual joy they feel in reminiscing about this strange past grants the film a level of humanity it desperately needs.

Grade: B. Rated PG-13. Starts March 29 at Grail Moviehouse

(Photo: Focus Features)