Two Anniversary Celebrants Paired Together - In 1955, the success story began for the 120 units of the class Ae 6/6 electric locomotive delivered to the Swiss Federal Railways. They quickly proved themselves, particularly on the Gotthard line, as the ideal motive power for hauling ever growing train loads at a brisk pace up the grades, because the "slowly creeping" Crocodiles took too long to negotiate this line. The attractive looking and speedy "Ae 6/6 power houses" quickly replaced Crocodiles and many locomotives with pilot trucks especially on steeply graded main lines. The newest locomotives have only started displacing the Ae 6/6 in the recent past from the latter's regular lines. Since then you can see these 50 year old anniversary celebrants almost exclusively in the middle of Switzerland on the point of heavy freight trains.