The Nez Cassé series of locomotives is a large family of electric and diesel locomotives intended primarily for fast passenger service on the French SNCF railway system. Produced by Alsthom for use under multiple electrification networks and un-electrified lines, they have been in widespread use from 1976 into the 21st century. Classes produced in the main series were BB 7200/7600 and CC 6500 under 1.5 kV DC, BB15000 under 25 kV 50 Hz AC, BB 22200 (7200+15000) and CC 21000 under dual 1.5 kV DC and 25 kV 50 Hz AC, and the diesel CC 72000/72100.

The SNCF CC 40100 was a French class of quad-voltage 4,340 kW (5,820 hp) electric locomotives. They were intended for high-performance passenger services on the Trans Europ Express (TEE) routes of the 1960s and 1970s. This non-stop international working required them to support the electrical standards of several networks. They are significant for combining three innovations in locomotive design: quad-voltage working, three-axle monomotor bogies and the new 'Nez Cassé' body style of French locomotives.