The ballad tells of a steel-driving man who beat a steam drill and died with a hammer in his hand. This episode strips away the folklore to find the historical figure: a 19-year-old from New Jersey named John William Henry, convicted of burglary and leased by the Virginia State Penitentiary to the C&O Railway to dig tunnels.

We explain what a steel driver and a shaker actually did, the difference between narrative ballads and slower hammer songs, sociologist Guy Benton Johnson's 1920s search at the Big Bend Tunnel and the railroad's conveniently burned records, and historian Scott Reynolds Nelson's 2006 discovery in prison ledgers pointing to the Lewis Tunnel, silicosis, and unmarked graves in the sand behind a white building by the tracks.

• Why hammer songs worked as a survival metronome in the tunnel
• The 13th Amendme ...