The BB 9003 and BB 9004 are two French DC electric locomotives with two driving axle bogies, delivered to the SNCF in 1952 and 1954 respectively.
Built at the same time as the BB 9001 and 9002, these four machines were designed to test the behavior of total adhesion locomotives in operation, and to define the mechanical and electrical characteristics of production machines for high-speed operation. In particular, the BB 9003 and 9004 are built to test the integration of a new type of motor bogie, designed by André Jacquemin. The BB 9004 set a world rail speed record (331 km/h) on March 29, 1955.
Like many other prototypes, their careers were short-lived, being written off in January 1973, but a locomotive named "BB 9004", actually rebuilt from the two prototypes, is on display at the Cité du Train.