During the fighting at Anzio in early 1944, the Allied troops on the claustrophobic beachhead heard the noise of monstrous artillery rounds roaring overhead that one veteran of the 7th Infantry Regiment described as “like a large cook stove going sideways.” Many of the men at Anzio had experienced the artillery barrages from the feared German 88, but these 280mm 550 pound shells dwarfed the 88. Although the troops on the beach regularly heard these shells, they almost always were headed out to sea targeting the ships that supported the campaign. The guns that fired the rounds were Krupp K5(E) railway guns, a direct descendent of the World War I Paris Gun that bombarded its namesake in the spring and summer of 1918.

The two K5s that fired on Anzio were installed on the Alban Hills, southeast of Rome. They were known to the Germans as Leopold and Robert; to the Allies they were nicknamed “Anzio Annie” and “Anzio Express” respectively. The Americans and British knew the relative location of the guns but were never able to find and destroy them because after firing a few rounds the crews rolled the guns into tunnels concealing them from Allied air power. Two men of the 157th Infantry Regiment had a close call with Anzio Annie while they were in a foxhole covered by timbers, sandbags, and a haystack. One of the men remembered hearing the shell coming in and taking “off the top of the haystack and land[ing] about ten feet behind us. It went off like it was the end of the world.” Another veteran recalled, “It felt like it was going to suck you out of your foxhole” when the rounds sailed by. The shells were splined to line up with the rifling in the barrel and possessed a booster that would fire in-flight. A soldier of the 45th Infantry Division said that “When the shell got over us, a booster would go off. It would scare the hell out of you. Of course if you heard the booster, you were safe, ‘cause it was already past you on its way to the harbor.”

In June 1944, Leopold and Robert were found abandoned in Civitavecchia, a port city outside of Rome. The 43-man German crews had attempted to destroy both guns but only Robert’s crew had been successful. Crewmember Albert Sauerbier recalled they had not been able to completely destroy Leopold because of the rapid advance of the Americans. When it was discovered, some of the men that had been shelled by Leopold signed the side of the carriage. Leopold’s gun and its car were shipped back to the United States in March 1945 as a curio. The Krupp K5s had more of a psychological, rather than physical, effect on most of the troops at Anzio. Chief of the Foreign Material Branch at Aberdeen Proving Ground, Lt. Col. George B. Jarrett wrote that “Such weapons have limited pay-off value” and that “These railway units could be classified as built to satisfy Hitler’s demands for massive and crushing engines of war.”