At the end of the Forties, the Swiss Federal Railways (SBB) grappled again intensively with the problems of hauling trains on the Gotthard route. Extensive studies led to the realization that a new type of locomotive had to be designed with six driving axles, without pilot trucks, with a weight of about 120 metric tons, and a performance of 4,300 kilowatts / 5,764 horsepower for the constantly increasing trainloads. After almost three years of development and construction time, the two prototypes of the Ae 6/6 were ready and put into operation in the fall of 1952 and January of 1953. After overcoming several teething problems and above all installing wheelsets with side play as well as reducing the flanges on the center wheelsets of the trucks, the SBB initiated regular production of the locomotive in 1954. A total of 118 additional units were delivered between 1955 and 1966. It quickly turned out that a great success was at hand with road numbers Ae 6/6 11401-11520 and a "new Gotthard locomotive" was sparkling in the locomotive heavens. The only shortcoming on the Ae 6/6 was its trucks, which proved to be real "rail grinders" on certain routes and caused excessive wear on the track.
The first 25 locomotives were often designated as canton locomotives, since they carried the coats-of-arms of the 25 Swiss cantons. There were decorative chrome strips on the sides and on the ends of the locomotive body. These decorations as well as the coats-of-arms on the side walls were very well received and made these powerful locomotives famous all over Europe. The rest of the 95 regular production locomotives were given the coats-of-arms for capital cities, important cities, and locations.
In the Fifties and Sixties, the Ae 6/6 units simply worked as the Gotthard locomotives in passenger as well as in freight service. Real competition did not arise until the appearance in 1975 of the Re 6/6 with almost double the power. The former Gotthard stars now had to make do with lesser services and wandered to Central Switzerland and the Jura Region. Starting in the mid-Nineties, they were seen pulling only freight trains. A first great wave of retirements took the locomotives in 2009/2010 and the last scheduled use of these units ended in December of 2013. The Ae 6/6 locomotives were worn-out. Fifteen units are currently preserved, of which six units are owned by SBB Historic alone. Among them is the operational locomotive, road number Ae 6/6 11421 "Grischun/Graubünden" in its original fir green paint scheme.