During the German occupation of Norway during the Second World War , the Luftwaffe commenced major upgrades to Gardermoen Air Station .
During the German occupation of Norway during the Second World War , the Luftwaffe saw the strategic value of a railway line to the installation .
During the German occupation of Norway during the Second World War , the Luftwaffe commenced major upgrades to Gardermoen Air Station , and saw the strategic value of a railway line to the installation .