SNCF Class BB 27300 the number carried on the locomotive is prefixed with the number 8, to denote the unit as belonging to the Île-de-France division of SNCF. The first locomotives entered service in 2006 on suburban trains from Paris Montparnasse railway station. Current deployment sees a total of 25 locomotives operating services from Paris-Montparnasse on trains to Dreux, Mantes-la-Jolie and Rambouillet. At Montparnasse they have displaced older SNCF Class BB 8500 and BB 25500 locomotives. A further 42 locomotives operate from Paris Saint-Lazare railway station on trains to Poissy, Mantes-la-Jolie, Pontoise, Gisors, and Ermont Eaubonne. At Saint-Lazare BB 8500 and BB 17000 locomotives
SNCF Class BB 12000 engines can support a very large overload current of 1800 amps, well over the 1000 amp design. They suffered very little wheel slip; they could pull 1756 tonnes trains on a 10 ‰ grade and 2885 tonnes trains on a 5 ‰ grade. The locomotives had few flaws, none of which related to the electrical components. They had cramped cabins, poor braking and couldn't work as multiple-unit sets. SNCF Class BB 12000 The SNCF Class BB 12000 were electric locomotives operated by SNCF. The first examples arrived on the railway in 1953, operating on the 25 kV 50 Hz line