The 5E and 5E1, developed in England, are considered the best-known South African electric locomotives. A total of 160 5E were built in three series by English Electric and the Vulcan Foundry. Since they were often used in multiple, they had gangway doors on the front sides. The first received the nickname “Klein Mamba” (“Little Mamba”) because of their coloring. The rest were also called “Balstamper” (“ball tamper”) because of their poor running characteristics. The improved 5E1 was developed by Metropolitan-Vickers. A total of 690 were built in five series, the first of which were built at Metropolitan-Vickers and the rest at the Union Carriage & Wagon Works.