Crocodile electric locomotives are so called because they have long "noses" at each end, reminiscent of the snout of a crocodile (see also Steeplecab). These contain the motors and drive axles, and are connected by an articulated center section. The center section usually contains the crew compartments, pantographs and transformer.
The name was first applied to Swiss locomotives. Sometimes the term is applied to locomotives in other countries of a similar design.
A prototype locomotive, SBB-CFF-FFS Ce 6/8 I number 14201, was ordered in June 1917. The production "Crocodiles" were the series SBB Ce 6/8 II and SBB Ce 6/8 III locomotives of the SBB, Swiss Federal Railways, built between 1919 and 1927. There were 33 class Ce 6/8 II and 18 class Ce 6/8 III, making a total (excluding the prototype) of 51 locomotives. These locomotives were developed for pulling heavy goods trains on the steep tracks of the Gotthardbahn from Lucerne to Chiasso, including the Gotthard Tunnel.