The Riebe-Kugellager factory at Berlin-Weissensee were building two prototypes of the K-Wagen which was a 148 ton tank which was supposed to be operational in 1919. Both were destroyed on orders of the Inter-Allied Control Commission after the war.
Captain Weger and Josef Vollmer were the designers.
There were very large sponsons on each side that held the main armament of 7.7 cm guns and machine guns.
The K-Wagens were made to be broken down into 15 to 20 tons sections that could then be transported by train.