The Siegfried Line campaign was a phase in the Western European campaign of World War II, which involved actions near the German defensive Siegfried Line.
This phase spanned from the end of the Battle of Normandy, or Operation Overlord and the pursuit across northern France, which ended on 15 September 1944, and concluded with the opening of the German Ardennes counteroffensive, better known as the Battle of the Bulge.
Background
German forces had been routed during the Allied break-out from Normandy. The Allies advanced rapidly against an enemy that put up little resistance. But after the liberation of Paris in late August 1944, the Allies paused to re-group and organise before continuing their advance from Paris to the River Rhine. The pause allowed the Germans to solidify their lines—something they had been unable to do west of Paris.
By the middle of September 1944, the three Western Allied army groups; the Anglo-Canadian 21st Army Group (Field Marshal Sir Bernard Montgomery) in the north, the United States U.S. 12th Army Group (Lieutenant General Omar Bradley) in the center, and the Franco-American 6th Army Group (Lieutenant General Jacob L. Devers) in the south, formed a broad front under the Supreme Allied Commander, General Dwight D. Eisenhower and his headquarters SHAEF (Supreme Headquarters Allied Expeditionary Force).
While Montgomery and Bradley each favored relatively direct thrusts into Germany (with Montgomery and Bradley each offering to be the spearhead of such an assault), General Eisenhower disagreed. Instead, he chose a "broad-front" strategy, which allowed the Allies to gain ground from the beaten Germans in all sectors, allowed the advancing Allied forces to support each other.
The rapid advance through France had caused considerable logistical strain, made worse by the lack of any major port other than the relatively distant Cherbourg in western France. Although Antwerp was seen as the key to solving the Allied logistics problems, its port was not open to Allied shipping until the Scheldt estuary was clear of German forces. As the campaign progressed, all the belligerents, Allied as well as German, felt the effects of the lack of suitable replacements for front-line troops.
There were two major defensive obstacles to the Allies. The first was the natural barriers made by the rivers of eastern France. The second was the Siegfried Line, which fell under the command, along with all Wehrmacht forces in the west, of Generalfeldmarschall Gerd von Rundstedt.
Logistics and supply
Although the breakout from Normandy had taken longer than planned, the advances until September had far exceeded expectations. Bradley, for example, by September had four more divisions than planned and all of his forces were ahead of their expected position. One effect was that insufficient supplies could be delivered to the various fronts to maintain the advance: demand had exceeded the expected needs.
Much war materiel still had to be brought ashore across the invasion beaches and through the one remaining Mulberry harbour (the other had been destroyed in an English Channel storm). Although small harbours, such as Isigny, Port-en-Bessin, and Courcelles, were being used, the major forward ports such as Calais, Boulogne, Dunkirk and Le Havre either remained in German hands as "fortresses" or had been systematically destroyed. The availability of Cherbourg had been valuable until the breakout, but then the shortage of transport to carry supplies to the rapidly advancing armies became the limiting factor.
Although fuel was successfully pumped from Britain to Normandy via the Pluto pipeline, this still had to reach the fronts, which were advancing faster than the pipelines could be extended. The railways had been largely destroyed by Allied attacks and would take much effort to repair, so fleets of trucks were needed in the interim. In an attempt to address this acute shortage of transport, three newly arrived U.S. infantry divisions—the 26th, 95th, and 104th—were stripped of their trucks in order to haul supplies. Advancing divisions of the U.S. 12th Army Group left all their heavy artillery and half their medium artillery west of the Seine, freeing their trucks to move supplies for other units. Four British truck companies were loaned to the Americans. Another 1,500 British trucks were found to have critical engine faults and were unusable, limiting assistance from that quarter. The Red Ball Express was an attempt to expedite deliveries by truck but capacity was inadequate for the circumstances.