Union Switch and Signal (US&S) was a supplier of railway signaling equipment, systems and services in Pittsburgh, Pennsylvania. As of January 1, 2009, US&S is known as Ansaldo STS USA. Ansaldo STS S.p.A. is a multinational technology company which produces signalling and automation systems for use by rail and rapid transit operators. The firm also acts as lead contractor and turnkey provider on new rail developments. Headquartered in Genoa, Italy ( REF: Wikipedia )