Union Switch & Signal in Pittsburgh
Established in 1881, Union Switch & Signal (US&S) was a leading enterprise specializing in railway signaling equipment and systems. The organization was founded by George Westinghouse, a renowned industrialist and inventor. The company’s headquarters were located in Swissvale, and close suburb of Pittsburgh, and it served clients worldwide.
Company’s Evolution
Founding and Early Years
The company was founded by George Westinghouse in 1881 with the merger of two other corporations, Union Electric Signal Company and Interlocking Switch & Signal Company. The former was known for its track circuit technology, while the latter had earned a reputation for its interlocking systems. The merging of these two companies marked the beginning of US&S.
Changes in Ownership
US&S functioned as an autonomous entity until 1917, when it was acquired by Westinghouse Air Brake Company (WABCO). In 1968, American Standard bought WABCO and restructured US&S as a separate division. The company went through yet another change of ownership in 1988 when Ansaldo STS, a global provider of signaling, control, and automation systems, acquired US&S.
Modern Developments
Ansaldo STS was later taken over by Hitachi, and in 2019 the company was renamed as Hitachi Rail STS. Throughout these changes, US&S continued to develop and innovate, playing a crucial role in shaping railway signaling systems.
Contributions to Railway Signaling
Power Interlocking System
US&S installed the first power interlocking system in the U.S. in 1882. This pneumatic system was soon replaced by an electro-pneumatic system, which was widely adopted across the country.
Automatic Train Stop
In 1901, US&S created the first electro-pneumatic automatic train stop system for the Boston Elevated Railway. This system was later implemented by the New York City Subway and other transit systems.
Crossing Gate
US&S introduced an electrically controlled highway crossing gate in 1908, contributing to the safety of road-rail intersections.
Inductive Train Control System
In 1923, US&S developed the first inductive train control system. This innovation paved the way for the development of coded track circuits and bi-directional cab signaling.
Signature Products
The “Teardrop” Mechanical Bell
One of the most loved creations of US&S is the Model 15A Highway crossing bell, patented in 1917. This bell, also known as the “Teardrop” bell, was used in early wig wag crossings and flashers.
Wartime Production
During World War I, the company manufactured the Le Rhône 9C, a 9-cylinder rotary engine, under license. It also produced M1911A1 pistols during World War II.
Modern Product Line
Level Crossing Signal
US&S’s modern product line includes level crossing signals, featuring model 95 gate mechanisms, 8″ and 12″ flashing lights, and bells. The company also provides cab signaling equipment and automatic train control, protection, and stop systems.
Wayside Signaling Equipment
Wayside signaling equipment offered by US&S comprises of DC code systems, electronic communication systems, electronic interlocking, relays, railway signals, switch machines, and track circuits.
Central Control Signaling Equipment
In the domain of central control signaling equipment, the company provides computer-based manual control systems, traffic management systems, dark territory control systems, and electro-mechanical centralized traffic control machines.
From its inception in 1881 to its evolution into Hitachi Rail STS, Union Switch & Signal has played a pivotal role in the world of railway signaling. Its innovative products and systems have revolutionized the industry, making railway transportation safer and more efficient.
