There exists substantial evidence that these shipments included Italian forced labour workers and trainloads of Jews in 1944 during the German occupation of northern Italy, when a German train passed through Switzerland every 10 minutes. The need for the tunnel was complicated by the British Royal Air Force having bombed and disrupted services through the Brenner Pass, as well as a heavy snowfall in the winter of 1944-45. Of 43 trains that could be tracked down by the 1996 Bergier Commission, 39 went via Austria (Brenner, Tarvisio), one via France (Ventimiglia-Nice). The commission could not find any evidence that the other three passed through Switzerland. It is possible that the train could have been carrying dissidents back from concentration camps. Started in 1944, some repatriation trains went through Switzerland officially, organised by the Red Cross.