The Class BB 8700 electric locomotives were rebuilt from the BB 8500 (or BB 88500) as the first subseries for the growth in Maurienne.
Indeed, while the CC 6500 participated in this task, the reorganization of traction in Maurienne had led them to other services. Since the BB 8500 had been restricted for some years to 150 km/h (93 mph), as a result of their poor suspension and for the comfort of the drivers, it was decided to re-use twenty for Maurienne. These were renumbered as Class BB 8700.
^ abcd"BB 8700 SNCF" [BB 8700 SNCF]. Trains d'Europe (in French). Retrieved 6 April 2017.