When the SBB needed new freight locomotives for the Swiss Plateau in the twenties, they ordered a development of the Ce 6/8^II, now called Ce 6/8^III. Despite having to be more powerful, this type had to be simpler than its predecessor. The requirements were that it could haul 1,400 tonnes at 35 km/h on one percent inclines or 520 tonnes at 30 km/h on 2.6 percent.

The general layout and electric equipment was nearly identical to its predecessor, but the transformer and traction motors were more powerful. One way to reduce the complexity was to use the Winterthur rod drive that was suitable for the required speed of 65 km/h instead of the complicated variant used on the Ce 6/8^II.

Although ordered for the Swiss Plateau, the 18 locomotives built in 1926 and 1927 immediately came to the Gotthard. There they served heavy freight service until the Ae 6/6 was introduced in the fifties and after this, they came to flatter lines. In 1956, the permitted speed was raised to 75 km/h, what led to the new designation Be 6/8^III. The last one was retired in 1977 and today, 13302 and 13305 are preserved and still operational.