St. Charles Air Line Bridge

The St. Charles Air Line Bridge is a bascule bridge that carries railroad tracks across the Chicago River. The structure uses a concrete counterweight system that allows the span to rise and permit boat traffic to pass underneath.

The bridge opened in 1919 and was initially the world's longest bascule span. It was relocated and shortened in 1930 to accommodate changes in the river's path.

The structure received designation as a Chicago Landmark in 2007, marking its engineering influence on the city's transportation heritage.

The bridge operates under Canadian National Railway management and remains in active use for freight and passenger trains. Visitors can view the structure from several vantage points along the riverbank.

The bridge became a Chicago Landmark in 2007 and operates with machinery that can raise its span within minutes to allow river traffic to pass. This balance between rail and water transportation reflects Chicago's unique dual-purpose infrastructure.

Location: Chicago

Official opening: 1919

GPS coordinates: 41.86080,-87.63440

Latest update: December 11, 2025 11:01