During the Second World War, contractors including Union Switch & Signal of Swissvale, PA received contracts to produce M1911A1 pistols. US&S was mainly a railway equipment company, but they were the last company to be contracted and the first contract to be cancelled due to contract requirements being reduced. US&S was able during 1943 to manufacture about 55,000 .45s, making this company the second lowest for production in pistols, but well ahead of Singer’s 500 pistols.