overall: 3 1/2 ft x 42 ft x 12 ft; 1.0668 m x 12.8016 m x 3.6576 m
Object Name:
Bridge Truss
Date made:
1844-1845
Description:
This span that once crossed Manayunk Creek in Pennsylvania is from the first iron truss bridge built in the United States. Richard Osbourne, the British-born chief engineer for the Philadelphia & Reading Railroad, designed this bridge in the 1840s, based on a cross-hatch wood truss pattern developed by the American engineer William Howe.
P&R shops crafted this span from cast and wrought iron, assembling it without bolts or screws, much like the timber joinery found in all-wood bridges of the era.
The railroad used the new, stronger iron bridges to speed coal trains from Schuykill Valley to Philadelphia coal yards, bypassing the less efficient canal system.
The Smithsonian collected this span in 1942, days before it was scheduled to be melted down as wartime scrap iron.
