The Swiss Class De 6/6 electric locomotives were built in 1926 for the Swiss Federal Railways. Ordered for the Seetalbahn line, which runs between Lenzburg and Emmenbrücke, they were Known as Seetal Crocodiles. In total 3 locomotives of this type were built, and numbered 15301–15303. As built they were capable of operating under dual voltage - the 5.5 kV, 25 Hz AC system in use on the Seetal line, and the national 15 kV 162⁄3 Hz AC system. The former system was removed from these locomotives in 1930, when the line was modernised to SBB national standards.