During the 1950s, transport demand and traffic increased in such a manner, that the existing "Crocodile" locomotives of the Ge 6/6 I series built in the 1920s and the Ge 4/4 I series locomotives built in 1947/1953 were not sufficient anymore. In 1958, the construction of large hydroelectric power plants (Albigna Dam) started in the Bergell region in southeastern Switzerland. To raise the dam, owned by the Elektrizitätswerk Zürich, to its planned height of 115m with a crown length of 791m, up to 1000 metric tons of concrete per day were needed. Produced in Untervaz close to the city of Chur, the concrete had to be transported to the Engadin valley. Rhaetian Railways needed a locomotive capable of hauling 250 metric tons over the 35‰ grades of Albula line. The Ge 6/6 II was born.