Johannsen's first road train consisted of a United States Army World War II surplus Diamond-T tank carrier, nicknamed "Bertha", and two home-built self-tracking trailers. Both wheel sets on each trailer could steer, and therefore could negotiate the tight and narrow tracks and creek crossings that existed throughout Central Australia in the earlier part of the 20th century. Freighter Trailers in Australia viewed this improved invention and went on to build self-tracking trailers for Kurt and other customers, and went on to become innovators in transport machinery for Australia.