SNCF Class BB 10003 locomotive was used as a test machine for operations of the TGV-TMST on 750 V and 3000 V. In 1998 the locomotive was converted back to a non-experimental class - as SNCF BB 15007. (SNCF Class BB 15000) The results were not as good as synchronous motor technology; it was not until the introduction of GTO transistor technology that series production of an asynchronous induction motored locomotive began in France, as the "Eurostar" TGV (1992), and later the BB 36000 "Astride" (1996). SNCF Class BB 10003 The locomotive SNCF BB 10003 was an experimental prototype locomotive converted from a SNCF
SNCF Class BB 20004 SNCF Class BB 20004 The SNCF class BB 20004 locomotive was a dual-voltage test-bed locomotive transformed from the damaged BB16540 in 1959. After the end of its test period in 1969 it was reinstated with its original equipment under its original number BB16540. SNCF had already experimented with three other dual-voltage locomotives in the 1950s, but these were all rebuilt from a DC locomotive and could only deliver their full power under 25 kV. Power output under 1.5 kV was reduced to 10% of the full power which is nearly negligible. This was however no real problem, as these locomotives