Oberkommando des Heeres
Koll remained on the Eastern Front until July 1942, participating in the Siege of Leningrad, Battle of Moscow and Rzhev-Vyazma Strategic Offensive Operation and returned to Germany. He was transferred to the Führerreserve and remained there until September 1942, when he assumed duty as Chief of Motor Vehicle Repair Matters in the Office of Oberkommando des Heeres.