Mallet locomotive
Orenstein and Koppel GmbH manufactured portable track. Krauss designed a 0-6-0T Zwillinge intended to be operated in pairs with the cabs together. The Zwillinge offered Mallet locomotive performance through tight curves, but damage to one unit would not disable the second. One-hundred-eighty-two Zwillinge were manufactured from 1890 to 1903, and shortcomings were evaluated in German South West Africa and China's Boxer Rebellion.