Two Chamberlain "Super 70" tractors, hooked together, using a locally built "Pederick" brand tandem hitch. This method of coupling gives a tremendous increase in traction and power to the ground, and was very popular for a short period of a few years in the late 1960's and early 1970's, as a method of reducing labour costs - whilst at the same time, increasing traction, and the ability to pull much wider tillage equipment. When you saw one of these units pulling several disc ploughs hooked together in the early 1970's, it was an impressive sight. The production of 4WD tractors such as the Steiger and Versatile saw the rapid end of these tandem hitches.