Westinghouse Air Brake Company
A pioneering American manufacturer of railway air-brake systems and related transport equipment.
Last updated August 24, 2026
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Overview
The Westinghouse Air Brake Company was an American industrial manufacturer established by George Westinghouse in 1869. Its origins lay in Westinghouse's development of compressed-air braking technology for railways, a major safety improvement at a time when trains relied heavily on manually operated brakes and systems that could fail across an entire train if a coupling broke. The company's products helped standardize automatic braking by allowing each railway car to carry an auxiliary air reservoir and brake cylinder controlled through the train's brake pipe. Westinghouse's first air-brake design was a straight-air system, but its limitations led to the development of the automatic air brake. In 1872, George Westinghouse introduced the triple-valve arrangement that made a loss of brake-pipe pressure apply the brakes automatically. The design was further improved by the quick-action triple valve, patented and tested in 1887, which accelerated emergency braking by locally venting air from the brake pipe on individual cars. These innovations reduced collision risks, longitudinal shocks, and the difficulty of stopping long freight and passenger trains. The company initially manufactured in Pittsburgh before relocating its principal air-brake plant to Wilmerding, Pennsylvania, in 1889. Its presence shaped Wilmerding's economy and civic life. The company employed thousands of people in the surrounding region, built or sold homes to workers, supported educational and cultural activities, and offered an early disability-benefit arrangement for eligible employees. It also became associated with comparatively progressive labor policies for its era, including a nine-hour workday and a Saturday-afternoon half holiday. At the same time, the town's dependence on a single major employer exposed workers and local businesses to seasonal fluctuations in industrial demand. By the early twentieth century, Westinghouse air brakes had been installed on millions of railway cars and tens of thousands of locomotives. The company expanded beyond railway braking. In 1921 it began producing a modified air-brake system for trucks and other heavy vehicles, and in 1930 its Westinghouse Automotive Air Brake Company combined with Bendix Corporation to form Bendix-Westinghouse Automotive Air Brake Company. In the 1930s, the company also developed Decelostat, a wheel-slide protection system intended to improve braking performance by reducing wheel lockup. A further diversification occurred in 1953, when the company acquired assets associated with heavy-equipment designer R. G. LeTourneau. Products sold under the LeTourneau-Westinghouse name included scrapers, cranes, bulldozers, and other construction and mining equipment. The business later shortened its name to Wabco and competed in the heavy-equipment market through the early 1980s. In 1984, the construction and mining equipment division was sold to Dresser Industries; the Haulpak high-capacity haul-truck line continued under Dresser and later became associated with Komatsu through a subsequent joint venture. The original enterprise subsequently gave rise to separate successor businesses rather than one single continuing corporation. Its railway activities became associated with Wabtec, which continues to supply railway equipment and maintains a connection with the Wilmerding air-brake operation. Its commercial-vehicle control activities developed into WABCO Vehicle Control Systems, later known as WABCO Holdings. WABCO Holdings was taken public by American Standard in 2007 and was acquired by ZF Friedrichshafen in a transaction announced in 2019 and completed in 2020. Because these successor companies became independently owned and operated, the historical Westinghouse Air Brake Company should not be treated as identical to either modern Wabtec or ZF's WABCO business.
History
George Westinghouse founded the Westinghouse Air Brake Company in 1869 after developing a compressed-air railway brake earlier that year. The early system used a locomotive-mounted air pump and reservoir, a driver's valve, a train pipe, and brake cylinders on the cars. Although it improved upon manual braking, the straight-air design had important weaknesses: braking did not propagate evenly through a long train, and a broken coupling or other loss of continuity could leave the train without effective braking. Westinghouse addressed these problems with the automatic air brake introduced in 1872. The system used a triple valve and an auxiliary reservoir on each car. Under normal conditions, pressure in the brake pipe maintained the system in a released state. A reduction in brake-pipe pressure caused the triple valve to direct air into the brake cylinder, applying the brakes. Because a loss of pressure triggered braking rather than disabling it, the arrangement provided a fail-safe principle that became fundamental to railway practice. In 1887, Westinghouse developed the quick-action triple valve. Tested on the Chicago, Burlington and Quincy Railway, the design accelerated emergency application by allowing each car to vent brake-pipe air locally, reducing the delay between braking at the front and rear of a train. The company manufactured in Pittsburgh during its early years and moved its air-brake plant to Wilmerding in 1889. A general office building followed in 1890 and is now recognized on the National Register of Historic Places. The company became deeply integrated into Wilmerding's social and economic structure. In the 1890s it employed approximately 3,000 people from the Pittsburgh area, with many workers living near the plant. The company was associated with relatively advanced employment practices for the period, including a nine-hour day, a 55-hour week, Saturday-afternoon half holidays, housing initiatives, educational and cultural programs, and an employee disability-benefit plan. These policies helped attract and retain skilled labor, although the town's reliance on the factory also meant that seasonal downturns affected household incomes and local commerce. By 1905, Westinghouse air-brake equipment had been installed on more than two million freight, passenger, mail, baggage, and express cars and approximately 89,000 locomotives. The company later applied its braking expertise to road transport. In 1921 it began making a modified air-brake system for trucks and heavy vehicles. Its automotive activities were reorganized in 1930 when Westinghouse Automotive Air Brake Company merged with Bendix Corporation to create Bendix-Westinghouse Automotive Air Brake Company. During the 1930s, Westinghouse also developed Decelostat, a wheel-slide protection system designed to prevent or reduce loss of wheel adhesion during braking. The company diversified again in 1953 through the acquisition of assets connected with R. G. LeTourneau. The resulting LeTourneau-Westinghouse business produced scrapers, cranes, bulldozers, and other construction and mining machinery. In 1967 it shortened its name to Wabco and competed in the heavy-equipment sector for roughly the next decade and a half. The entire construction and mining equipment division was sold to Dresser Industries in 1984. The Haulpak truck range remained in production under Dresser and later continued through a Dresser-Komatsu joint venture. The historical company ultimately led to two principal successor paths. The railway-equipment activities became associated with Wabtec, a railway technology company formed through the combination of railway businesses including MotivePower. The commercial road-vehicle control activities became WABCO Vehicle Control Systems and later WABCO Holdings, headquartered in Switzerland. WABCO Holdings became publicly traded in 2007 after being separated by American Standard. In March 2019, ZF Friedrichshafen announced a proposed acquisition of WABCO Holdings for approximately $7 billion; completion occurred in 2020. The United States Department of Justice required the divestiture of WABCO's North American heavy-vehicle steering-components business, principally associated with R. H. Sheppard, to address competition concerns. These developments demonstrate that the Westinghouse Air Brake name survives primarily through distinct successor lineages rather than through a single unified modern corporation.
- 2020
WABCO Holdings acquired by ZF
[1]ZF Friedrichshafen completed its acquisition of WABCO Holdings after regulatory review and a required divestiture.
- 1984
Construction and mining division sold
[1]Wabco's construction and mining equipment division was sold to Dresser Industries.
- 1967
Business adopts Wabco name
[1]The heavy-equipment operation shortened its name from LeTourneau-Westinghouse to Wabco.
- 1953
Heavy-equipment diversification
[1]Assets associated with R. G. LeTourneau were acquired, creating the LeTourneau-Westinghouse heavy-equipment business.
- 1930
Automotive brake merger
[1]Westinghouse Automotive Air Brake Company merged with Bendix Corporation to form Bendix-Westinghouse Automotive Air Brake Company.
- 1921
Entry into heavy-vehicle braking
[1]The company began producing modified air-brake systems for trucks and other heavy vehicles.
- 1889
Plant moved to Wilmerding
[1]The main air-brake manufacturing plant moved to Wilmerding, Pennsylvania, establishing the town as the company's principal industrial base.
- 1887
Quick-action triple valve developed
[1]George Westinghouse developed a quick-action triple valve that improved emergency braking throughout long trains.
- 1872
Automatic air brake introduced
[1]The company introduced the automatic air brake using a triple valve and individual car reservoirs, making loss of brake-pipe pressure apply the brakes.
- 1869
Company founded
[1]George Westinghouse established the Westinghouse Air Brake Company in Pittsburgh after inventing a railway air-brake system.
Products and positioning
An engineering-led safety and control systems manufacturer whose historic reputation was built on making railway braking more automatic, rapid, and reliable.
Railway braking · 1869
Straight air brake
The company's early compressed-air braking arrangement used a locomotive air pump, main reservoir, engineer's valve, train pipe, and brake cylinders on the cars. It represented a major advance over manual braking but was not automatic and could apply unevenly through a long train. A failure such as a broken coupling could also remove braking capability from the entire train, motivating Westinghouse's later automatic design.
Railway braking · 1872
Automatic air brake
Introduced in 1872, the automatic air brake used a triple valve and an auxiliary air reservoir on each car. Normal pressure kept the brakes released, while a reduction in train-pipe pressure caused the valves to apply the brakes. This fail-safe operating principle improved the safety and controllability of freight and passenger trains and became the foundation of the company's railway business.
Railway braking · 1887
Quick-action triple valve
The quick-action triple valve was developed to reduce the delay between brake application at the locomotive and at the rear of a long train. In an emergency, each car could vent air from its portion of the brake pipe, accelerating local application. The technology addressed the shock and stopping-distance problems associated with slow propagation of brake commands.
Commercial vehicle braking · 1921
Commercial-vehicle air-brake systems
Beginning in 1921, the company adapted its compressed-air braking expertise for trucks and other heavy road vehicles. These systems extended the Westinghouse control and safety approach beyond railways and ultimately contributed to the commercial-vehicle control-systems successor businesses associated with WABCO.
Wheel-slide protection · 1930
Decelostat
Decelostat was a wheel-slide protection system developed in the 1930s. It was intended to detect or respond to excessive wheel deceleration during braking, helping preserve wheel adhesion and reduce the risk of wheel flats. It illustrates the company's expansion from basic air-brake hardware into braking control and protection systems.
Construction and mining equipment · 1953
LeTourneau-Westinghouse heavy equipment
Following the 1953 acquisition of R. G. LeTourneau-related assets, the company sold construction and mining equipment under the LeTourneau-Westinghouse name. The range included scrapers, cranes, bulldozers, motor graders, off-highway trucks, and mining equipment. The division later operated under the Wabco name before being sold to Dresser Industries in 1984.
Brand decisions
2019
Agree to the acquisition of WABCO Holdings by ZFM&ABackground
WABCO Holdings had become the independently operated commercial-vehicle control-systems successor to the historical Westinghouse Air Brake business.
Action taken
ZF Friedrichshafen announced an agreement to acquire WABCO Holdings. United States antitrust authorities required the sale of the North American heavy-vehicle steering-components business to preserve competition.
Aftermath
The acquisition was completed in 2020, placing WABCO's commercial-vehicle activities within ZF while leaving the railway successor Wabtec independent.
Announced transaction value. Approximately US$7 billion (2019 announcement)
1984
Sell the construction and mining divisionM&ABackground
Wabco's construction and mining activities included motor graders, off-highway trucks, dump trucks, motor scrapers, and related manufacturing facilities.
Action taken
The entire construction and mining equipment division was sold to Dresser Industries.
Aftermath
The Haulpak truck range continued under Dresser and later through a Dresser-Komatsu joint venture.
1953
Diversify into construction and mining equipmentStrategyBackground
The company sought to broaden its industrial business beyond railway and vehicle braking.
Action taken
It acquired assets associated with R. G. LeTourneau and marketed heavy machinery under the LeTourneau-Westinghouse name.
Aftermath
The business competed in heavy equipment until the division was sold to Dresser Industries in 1984.
1872
Adopt the automatic air-brake principleProduct launchBackground
The initial straight-air system was vulnerable to uneven application and could leave a train without braking after a loss of continuity.
Action taken
Westinghouse introduced a triple-valve system with an auxiliary reservoir on every car, causing a pressure reduction to apply the brakes automatically.
Aftermath
The design established the core safety principle and product platform for the company's railway business.
Recent events
- 2019
ZF announces acquisition of WABCO Holdings[1]
M&A · Regulation
ZF Friedrichshafen announced an agreement to acquire WABCO Holdings. The transaction was subsequently completed in 2020, subject to a divestiture required by United States antitrust authorities.
- 2007
WABCO Holdings completes initial public offering[1]
M&A · Other
American Standard floated WABCO Holdings in an initial public offering, separating the commercial-vehicle control-systems successor from the historical railway business.
- 1968
American Standard purchases Wabco[1]
M&A
American Standard acquired Wabco after the business had broadened from railway braking into heavy equipment and other industrial activities.
- 1953
Westinghouse Air Brake Company expands into heavy equipment[1]
Other
The company acquired assets associated with R. G. LeTourneau and entered the construction and mining equipment market under the LeTourneau-Westinghouse name.
- 1889
Westinghouse Air Brake Company relocates its air-brake plant to Wilmerding[1]
Other
The company's principal air-brake manufacturing operation moved from Pittsburgh to Wilmerding, Pennsylvania, where it became the central industrial institution of the community.
Sources2 sources
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