SNCF's BB 25500 class are part of a series of electric locomotives built by Alstom. They are the dual system version of the BB 17000 (AC) and BB 8500 (DC) locomotives (17000+8500=25500). They are fitted with monomotor bogies with two different gear ratios. This allows them to have increased tractive effort in exchange for a reduction in top speed. This makes them suitable for both freight and passenger trains. They were built in three distinct batches leading to detail differences. They remain in use as mixed traffic locomotives, mostly with TER and Transilien. Locomotives 25517, 25518, 25523, 25528, 25572 & 25576 have been exported to Romania. They work with former SNCF Rio carriages for Regiotrans. Services worked are: The locomotives have been renumbered by adding 400,000 to their SNCF numbers.