For Chicago Bridge Enthusiasts

B & O Railroad, Bascule Span, detail of concrete counterweight.

B & O Railroad, Bascule Span, superstructure.

B & O Railroad, Bascule Span, through the portal.

Chicago River, Bascule Bridge, builder's plate.

Chicago Avenue Bridge, counterweight trunion rack and pinion.

Chicago Avenue Bridge, trunion from river pier.

These large format photographs of Chicago bridges were taken in the 1970's for the Historic American Engineering Record. The Record is one of three collections (Historic Buildings Survey and Historic American Landscapes Survey being the others) that is housed in the Library of Congress. These collections are among the largest and most heavily used in the Library. Together the collections are comprised of 556,900 measured drawings, large-format photographs and written histories documenting America's built environment.