"Thanks to their low dead weight, the Cars were primarily used in areas where it was only possible to transport low tensile loads due to gradients. Right into the 1960s, the H�llentalbahn ("Hell Valley Railway") from Freiburg to Neustadt and Seebrugg was one of the most important routes. In addition to running behind railcars, the trailer cars also often ran with battery railcars. All classes suffered significant losses during the Second World War. DB primarily converted the Civ-33 into control cars for battery railcars. However, some vehicles remained that could only be used as trailer cars and there were also some control cars for railcars. Following the decommissioning of the last battery railcars, the remaining control cars were put into the railway carriage fleet once again and were decommissioned once the useful service life was over."