Baureihe (Class) 120 can be considered one of Deutsche Bundesbahn's most audacious projects ever. Unlike all former electric locomotives, it was to run on rotary AC generated from the two-phase catenary AC by power electronics and it was to feature regenerative braking. 120 was conceived as an all-around loco, suitable for driving fast passenger trains as well as heavy freight trains. Development took rather long: the go for the project was given in 1976, prototypes were delivered by the usual suspects, i.e. the Henschel-Krauss-Maffei-Krupp-AEG-BBC-Siemens consortium beginning in 1979, yet the first 120s took up service for DB in 1989. Due to their versatility and their small number (just 60 of the regular series were built), the 120s were under immense pressure (nearly 24/7 service was the schedule for some of them) and acquired a bad reputation, for some predictably failed under the immense loads. When the 120s went into service, their revolutionary semiconductor power converter / rotary AC technology had already spawned a much more famous piece of rolling stock: the InterCity Express's ancestor, InterCity Experimental.
Technical fact sheet:
- Concept: Bo'Bo' layout (four axles in two bogies), all axles driven, disc brakes; German 15 kV/16-2/3 Hz catenary AC is transformed into rotary current for the four motors by electronical power converters
- Power: 5,600 kW sustained
- Traction: 340 or 290 kN maximum, depending on date built
- Top speed: 200 km/h allowed; in 1984 a 120 achieved the record speed of 265 km/h
- Total weight: 83.2 tonnes (20.8 tonnes per axle)
- Length: 19.2 m
- Distance between axles in bogie: 2.8 m
- Width: 2.95
- Number in service: 60