French State Railway BB 9001 and 9002

The BB 9001 and 9002 were two prototypes built in the SNCF's effort to transition from fast electric locomotives with carrying axles to all-adhesion locomotives. Both were built by the SLM in 1953 with their electric part being supplied by BBC. In many respects, they were similar to the BLS Ae 4/4, but were built for 1.5 kV DC. A difference between both prototypes was that the first one was controlled electrically, while the second one was controlled electro-pneumatically. They formed the basis for the development of the BB 9200 and BB 9300. After being used on some important express trains, the prototypes were replaced in this role by the BB 9200 from 1958. They were finally withdrawn in 1971 and 1972.