The St. Charles Air Line Bridge is a Strauss Trunnion bascule bridge

Bascule bridge

A bascule bridge is a moveable bridge with a counterweight that continuously balances the span, or "leaf," throughout the entire upward swing in providing clearance for boat traffic....

 which spans the Chicago River

Chicago River

The Chicago River is a system of rivers and canals with a combined length of that runs through the city of the same name, including its center . Though not especially long, the river is notable for being the reason why Chicago became an important location, as the link between the Great Lakes and...

 in Chicago, Illinois.

Built as part of the St. Charles Air Line Railroad

St. Charles Air Line Railroad

The St. Charles Air Line is a jointly-owned rail line located in Chicago, Illinois. It is owned by the BNSF Railway , Union Pacific Railroad , and Canadian National Railway ....

 by the American Bridge Company

American Bridge Company

The American Bridge Company is a privately held civil engineering firm specializing in the construction and renovation of bridges and other large civil engineering projects, founded in 1900, and headquartered in Coraopolis, Pennsylvania, a suburb of Pittsburgh.-Products and industry positioning:The...

in 1919, the bridge originally had a span of 260 feet (79.248 m). This bridge held the world record for longest bascule-type span until 1930, when it was shortened to 220 feet (67.056 m) during a relocation as a result of straightening the river channel. The chief design engineer of the original bridge was Leonard O. Hopkins.

External links

• Historic American Engineering Record (HAER) No. IL-157, "St. Charles Air Line Bridge"
• Historic Bridges of Michigan and Elsewhere