The CC 21000 was a class of electric locomotives in service with the French railways SNCF, built by Alsthom in 1969 and 1974.

Initially allocated to Dijon, the first two, CC 21001 and CC21002, were fitted with cab signalling to allow them to operate test trains on the new high speed lines.

This engine was rebuilt by Alstom with its transformer and electrical components replaced with those compatible with Amtrak's 25 Hz traction power system, taller pantographs, Amtrak's cab signaling system, US style couplers, a bell, and other components required by the AAR for operation on US railroads.

However, the X996's suspension system proved unsuitable for the relatively rough US track construction, and despite modifications made over the course of testing, the engine's performance was deemed unsatisfactory for Amtrak's use.

After testing was completed, X996 was returned to France, reverted to its pre-Amtrak appearance and specifications, and continued to operate on the SNCF.