In the campaigns against Poland, Denmark, France, Yugoslavia, Greece etc. the newly acquired standard gauge networks could be used without difficulty. By contrast, after the start of the invasion of Russia on 22 June 1941, the problem arose of transferring troops and materiel to Soviet broad gauge lines or converting them to German standard gauge. Confounding German plans, the Red Army and Soviet railways managed to withdraw or destroy the majority of its rolling stock during its retreat. As a result, German standard gauge rolling stock had to be used for an additional logistic role within Russia; this required the laying of standard gauge track. The price was high: Reichsbahn railway staff and the railway troops of the Wehrmacht had to convert a total of 16,148 kilometres of Soviet trackage to German standard gauge track between 22 June and 8 October 1941.