The 406th Engineer Combat Company, the fourth element, with 168 men under Captain George Rebh, provided perimeter security for the operations. Its soldiers were trained as actual combat engineers and could fight if the deception broke down and the unit was attacked. They also contributed to the visual convincing of the fake formations by creating the physical traces — tracks, disturbed ground, staged equipment positions — that would make the dummy vehicles more convincing.
## The 3133rd: A Separate Story
The 3133rd Signal Service Company Special was a related but distinct unit that deserves separate treatment.
The 3133rd was activated on June 21, 1944, at Pine Camp, New York, under Major John Williams, with ten officers and 192 enlisted men. It was formed around a cadre drawn from the 3132nd and used similar equipment and techniques, but it was not part of the 23rd Headquarters Special Troops. It was a separate organization deployed to a separate theater.
Where the 23rd operated in northwestern Europe — France, Belgium, Luxembourg, Germany — the 3133rd was sent to Italy. The unit sailed for Naples on March 1, 1945, and joined what was designated Operation Craftsman, a deception effort supporting the Allied offensive against the Gothic Line in northern Italy.
The 3133rd’s equipment differed from the 3132nd’s in one notable respect: rather than mounting its speakers on standard halftracks, the unit installed them inside converted M-10 tank destroyers, whose actual guns had been replaced with dummies to make room for the acoustic equipment.
The unit ran two significant deceptions in its brief Italian campaign. The first, on April 4 and 5, 1945, was in the Serchio Valley. The second, on April 14 and 15, was near Bologna, as the Allied spring offensive was pushing the Germans back through northern Italy. A German commander reportedly acknowledged afterward that he had been misled by the deception. The 3133rd earned a campaign star for the Po Valley Campaign.