In the huge covered roundhouse (Rotonde) in Chambéry with a diameter of 108 meters, which is used for the maintenance and storage of SNCF locomotives and railcars, there are four tracks for historic locomotives of the l'Association pour la Préservation du Patrimoine Ferroviaire Savoyard (APMFS). The CC # 6051, later CC # 20001, of the SNCF is a French two-system electric locomotive that could be used both on the line section Aix-Les-Bains-Annecy-La Roche sur Foron, which was electrified with 20 kV 50 Hz on a trial basis and later with 25 kV 50 Hz, and under 1500 V direct current. It was the first French locomotive to be built for operation with single-phase alternating current and at the same time the first multi-system locomotive in the world, even if the power under direct current was more of an auxiliary drive. From a mechanical point of view, this locomotive is regarded as the forerunner of the SBB Ae 6/6. The CC # 6051 was built by SLM together with the MFO and delivered to the Chambéry depot on September 9, 1950. On the following September 16, electric operation began, initially on the Aix-Les-Bains-Annecy section, and from May 10, 1951 to La Roche sur Foron. The CC # 20001 was in service until April 1980 and had covered a total of 2,430,000 kilometers. The locomotive is ready to roll and an operational refurbishment is planned.
