U.S. Steel Corporation, Clairton Works, 14-Inch Mill Engines No. 1 & No. 2, 400 State Street, Clairton, Allegheny County, PA

Steam Machines, Engines, Locomotives. In 1781 James Watt patented a steam engine that produced continuous rotary motion. Watt's ten-horsepower engines enabled a wide range of manufacturing machinery to be powered. The engines could be sited anywhere that water and coal or wood fuel could be obtained. By 1883, engines that could provide 10,000 hp had become feasible. The steam engine was one of the most important technologies of the Industrial Revolution.