In the late 1950s the narrow gauge Rhetian Railway (RhB) of Switzerland recommended stronger locos for haevy freight and passenger service. After a pre-series of two six axle locos (#701 and #702) the RhB ordered a series of five more locos (#703 - #707) that show differences in front design. Technical equipment of the locos is the same. The end trucks are interchangeable with those of four axle Ge 4/4 I. The locos develop 2398 HP and reach a maximum speed of 80 km/h. Even after around 50 years the RhB still uses the locos in daily service.
