Canal Street railroad bridge
|Canal Street railroad bridge|
Aerial view showing Canal Street railroad bridge (midground)
|Official name||Pennsylvania Railroad, Canal Street Railroad Bridge|
|Designer||Waddell & Harrington|
|Longest span||272.8 feet (83.1 m)|
|Construction begin||September 4, 1913|
|Construction end||July 30, 1914|
|Heritage status||Chicago Landmark|
The Canal Street railroad bridge (or Pennsylvania Railroad bridge) is a vertical-lift bridge across the south branch of the Chicago River in Chicago, Illinois. When it was constructed in 1914, its 1500-ton main span was the heaviest of any vertical lift bridge in the United States. It is the only vertical-lift bridge across the Chicago River, and it was designated a Chicago Landmark on December 12, 2007.
The present bridge was constructed for the Pennsylvania Railroad to replace a two-track swing bridge at the same location. The necessity to allow both continued use of the swing bridge and unimpeded river traffic during building work complicated construction of the bridge. The chosen solution was to construct the bridge in the raised position above the old bridge, then demolish the old bridge once construction was completed. The bridge was designed by Waddell & Harrington, and fabricated and erected by the Pennsylvania Steel Company.
Construction of the south tower began on September 4, 1913. When the two 185-foot (56 m) towers were completed, falsework for the main span was constructed in a fan shape that allowed the main span to be constructed in the raised position 130 feet (40 m) above the river.
The bridge carries two railroad tracks across the Chicago River at an angle of about 40 degrees to the center line of the river. Upon completion, the main span could be raised 111 feet (34 m) in about 45 seconds. By 1916, each day the bridge was crossed by about 300 trains, and was raised for river traffic about 75 times.
- Holth, Nathan. "Canal Street Railroad Bridge". Historic Bridges of Michigan and Elsewhere. Retrieved 2009-04-30.
- Smith, W.L.; Priest, W.W. (1915). "The Design and Erection of the Pennsylvania Lift Bridge No. 458 Over the South Branch of the Chicago River". Journal of the Western Society of Engineers (Chicago, IL: Western Society of Engineers) XX: 478–500. Retrieved 2009-04-30.
- "Pennsylvania Railroad, South Branch Chicago River Bridge, Spanning South Branch of Chicago River Bridge east, Chicago, Cook County, IL". Historic American Engineering Record. Retrieved 2009-04-30.
- CHICAGO LANDMARKS: Individual Landmarks and Landmark Districts designated as of January 1, 2008 (PDF). Commission on Chicago Landmarks. 2008-01-01.
- Waddell, James Alexander Low (1916). Bridge Engineering 1. New York: John Wiley & Sons Inc. p. 734. Retrieved 2009-04-30.