Ken McCrary, 73, and Ed Kimball, 19, are the museum’s steam shovel instructors. It takes two instructors because it takes at least two people to operate the 1932 Bucyrus-Erie 50-B steamer.

Gigantic Bucyrus steam shovels scooped tons of earth. Railroad cars ran continuously on a double track, dumping the tailings to form the Charges dam. By December 1905, yellow fever had been ...