French State Railway BB 20200

The BB 20200 was a member of the “BB Alsthom” family that was intended for mixed traffic across the borders with Germany and Switzerland. They were created by taking 13 BB 25500 from the production line and adding the equipment needed for operation under 15 kV and 16⅔ Hz. The basic locomotives were already capable of operation under 25 kV 50 Hz and under 1.5 kV DC. This also meant that these locomotives had monomotor bogies which could be switched between a top speed of 90 and 140 km/h while stationary. All locomotives were equipped for push-pull operations and double-heading. As their short bogie wheelbase led to bad running characteristics at speed, they were almost always used in freight service and rarely in passenger service. Another downside was that they only delivered 1,660 kW on 15 kV, compared to 2,940 kW at 25 kV. The last ones were retired in 2006 and BB 20210 is being preserved in the “Cité du Train” at Mulhouse.