The Pennsylvania Canal across Pennsylvania was an engineering triumph with a spectacular 37-mile railroad portage over the Allegheny Mountains. For half a century between 1820 and the Civil War, packet boats pulled by mules navigated through the canal.
Canal boats crossed the Allegheny River to Pittsburgh on the world's first successful cable suspension aqueduct or "water bridge". When the original canal aqueduct collapsed into the river, John Roebling was hired to build a new one. Roebling became a world-renown bridge designer, famous for the 1879 Brooklyn Bridge. He invented "wire rope", a strong iron cable, and used it in all his bridges after his experiment here with the Allegheny Aqueduct in 1844.
Roebling's aqueduct consisted of a wood trough filled with water and suspended from two iron cables. The cables were strung in place, wire by wire, and then anchored in eyebars embedded in masonry. The aqueduct was 160 feet long and contained 2,000 tons of water. Six boats loaded with passengers and goods could cross the river at the same time.
As the aqueduct filled with water for the first time, the event attracted one of the most enthusiastic crowds Pittsburgh had ever witnessed. Over 10,000 spectators watched while 100 guns saluted the first boats to float across the new aqueduct.
As canal technology became obsolete, Roebling's aqueduct was demolished in 1861 when the expanding Pennsylvania Railroad put the canal out of business.