Prototype Information

Following the electrification of the Gotthard line, the main lines in the midland region were also covered by overhead contact wires. This made it necessary to put in an order for electric mainline locomotives of a new design, as the types used on the Gotthard mountain were unsuitable for the midland region due to their low maximum speed. SBB initially ordered three different versions so that each of the manufacturers BBC, SAAS and MFO had the opportunity to prove the efficiency of their design. This led to the locomotive types Ae 3/6I, Ae 3/6II and Ae 3/6III with varying drive concepts. The Ae 3/6I design with Buchli drive prevailed and was built in several lots. A total of 114 locomotives were built, and later further developed for a higher power output with an additional drive axle as the Ae 4/7.

The Ae 3/6I locomotives were put into operation between 1921 and 1929, and remained in regular service for over 70 years. Initially deployed in the superior express service along the East-West axis, these locomotives also proved their worth in regional, postal and freight train services. They could be found in all three regions of the country and on all lines, whereby the Gotthard line tended to be the exception rather than the rule, because the Ae 3/6I was only used “on the mountain” at the beginning of its deployment, and after that only in exceptional cases.

Some locomotives were regularly hired by private railways, such as the BLS, which repeatedly used Ae 3/6I engines on its railway network over a period of 14 years. Six locomotives representing all three main construction types have been preserved and are in part operational: 10601 (in private hands), 10639 (in private hands), 10650 (Mikado Association), 10664 (SBB Historic), 10693 (Mikado Association) and 10700 (SBB Historic).