six restored the average repair time was five days per bridge. The cumulative effect of this kind of damage simply saturated the German capabilities for rail repair. 
Despite Allied domination of the air over the Ardennes, the Eifel, and the Rhine plain, the battlefield itself and the German armies therein never were isolated. Could the isolation of the battlefield have been accomplished? The terrain, with its sequence of river barriers and multitude of winding, steep gradients, was favorable to air interdiction. But the tactical ingredients and formula to achieve complete success were missing in late 1944. Sturdy rail bridges, particularly when defended by ground to air fire, proved hard to damage and even harder to destroy. Even the smaller bridges, such as those attacked in the Ahr River campaign, took some 250 tons of high explosive to cripple. Rail cutting attacks caused traffic islands but never succeeded in rooting out these islands or the movement between them. Movement by thin-skinned vehicles on trails, roads, and highways seemed particularly vulnerable but the physical blockage of the roads, as distinct from vehicular destruction, could be achieved only at particularly favorable points and for relatively short intervals of time. Finally, the Allied inability to operate aircraft in a ground assault role during the night and the long stretches of bad flying weather provided a built-in guarantee that the minimum supply and reinforcement requirements of the German armies would be met.
Although the Allied air forces failed to isolate the Ardennes battlefield, they did succeed in these days in dealing the Luftwaffe a mortal blow, thus making the task of their comrades on the ground much easier in 1945, on both the Western and the Eastern Fronts. Generalleutnant Adolf Galland, commander of the Luftwaffe fighter arm, has written the Luftwaffe epitaph in this manner: "The Luftwaffe received its death blow at the Ardennes offensive. In unfamiliar conditions and with insufficient training and combat experience, our numerical strength had no effect. It was decimated while in transfer, on the ground, in large air battles, especially during Christmas, and was finally destroyed." 
During the years following the invasion of Poland the German munitions of war had wasted away, so much so that in December 1944 the German armies in the Ardennes were fighting a poor man's battle. The total stock of 105-mm. gun-howitzer ammunition at the beginning of November 1944 was only half the size of the stock available on 1 September 1939 and the number of 105-mm. rounds was less than a third the number stocked in Germany at the beginning of the Polish campaign. It was still possible even so to gather a substantial ammunition reserve for the Ardennes offensive, and after the war
 This section is based on the extensive research done by Charles V. P. von Luttichau in his manuscript German Rail Communications in the Ardennes Offensive 1944-1945, and Royce L. Thompson's equally careful and detailed study Tactical Air Phase of the Ardennes Campaign Neither of these manuscript studies has been published, but both should be of great interest to students of logistics.
 Adolf Galland, The First and The Last (New York: Henry Holt & Co., 1960), p. 242.