Their popularity grew, gradually, through the 1930's and 1940's, but did not become commonplace until after the Second World War. During the period of 1946-1958, diesel locomotives virtually wiped out steam locomotives on America's railroads. The age of steam was dead. The diesel was now king. Electric motors or traction motors actually power the locomotive using the electricity produced by the generators.
All units are serviceable and see regular service on museum trackage during the summer months.