The F7 was the fourth model in EMD's line of F-unit locomotives, and by far it's best-selling cab unit. It succeeded the F3 model in GM-EMD's F-unit sequence, and was replaced in turn by the F9. A total of 2,366 cab-equipped lead A-units and 1,483 cabless booster or B-units were built. The F7 was the motive power of some of the most famous American trains including the Santa Fe's Super Chief and El Captain services.
The standard for all of Santa Fe's passenger locomotives, the Warbonnet is considered by many to be the most recognized corporate logo in the railroad industry. Early in the Amtrak Era, Santa Fe embarked on a program to paint over the red bonnet on its F units that were still engaged in hauling passenger consists with yellow (also called Yellowbonnets) or dark blue (nicknamed Bluebonnets), as it no longer wanted to project the image of a passenger carrier.