Bavarian ES 1

In the development of a single-axle drive for electric locomotives, one of the approaches was to use the Buchli drive, as used in Switzerland. The 21 locomotives of the series initially designated as the Bavarian ES 1 were equipped with it and were put into operation by the Reichsbahn as the E 16. They were used by the Bundesbahn until 1980 and were still the only locomotives in Germany with this technical solution. The Buchli drive was characterized by the fact that each traction motor was located above the axle in the locomotive body and transmitted its power to the axle via a single-sided mechanism that absorbed the vibrations. Power was again transmitted between the large gear wheel and the axle via coupling rods. This design is externally recognizable by the cover of the gear wheel. Although the technology was highly complex, it allowed to completely decouple the motors from the impacts of the rails.

Control was via a new type of linear mechanical tap changer, which had been used shortly before on the E 32. Its further development was later also used in the standard electric locomotives of the Bundesbahn. The chassis of the first five locomotives was designed with two bogies, each consisting of one leading axle and two powered axles. This solution did not work, and so the following locomotives were designed with driving axles in a main frame and Krauss-Helmholtz bogies. The first five were also converted to this form directly afterwards.

The first ten locomotives were given the Bavarian designation ES 1 when they were delivered in 1926. They had an hourly and continuous output of 2,340 and 2,020 kW and were soon renumbered E 16 01 to 10. Seven more followed in the following year as numbers E 16 11 to 17. Their output had increased to 2,580 and 2,400 kW respectively. Finally, four more were ordered in 1932 with the numbers E 16 18 to 21. Due to technical advances, the output was now 2,944 and 2,655 kW.

Despite their unusual method of transmission, the locomotives were used for a very long time. Only two were lost in the war, all the rest were taken over by the Bundesbahn. There only the E 16 12 had to be retired in 1967 due to an accident, all other 18 locomotives were redesignated class 116 in 1968. These were retired between 1973 and 1980.