[6] In 1988, Ansaldo STS, a global supplier of signaling, control and automation systems, purchased US&S from American Standard.

[10] US&S built the first power interlocking system in the United States, a pneumatic design, in 1882 at East St. Louis, Illinois.

This bell has appeared on advertising literature for railroad signals as far back as the 1920s as far abroad as Chile and Italy on early wig wag crossings and flashers.

There have been subtle variations in the Teardrop bell over the years ranging from different sized electric coils, inclusion of the patent date on the rain hood, as well as a very early version with a less characteristic rain hood that simply read "UNION, patent pending."

This bell is treasured by many signal collectors for its slow, low pitched ring at an irregular cadence.

During the World War I the Le Rhône 9C 9 cylinder rotary engine was manufactured under license by Union Switch & Signal.

[14] Union Switch & Signal was one of the five contractors (including Colt, Remington-Rand, Ithaca Gun Company, and Singer Sewing Machine) to make M1911A1 pistols during World War II.

With the government-owned machine tooling already in place at US&S, they were offered a subcontract arrangement to produce M1 Carbine components.