Tower derrick used for Mackinac Bridge construction (5 of 6)

Taking apart the tower derrick, Electronic reproduction of text.  The Mackinac Bridge 1954 - 1958. Mackinac Bridge Authority
Abstract/Description: Taking apart the tower derrick
Subject(s): Bridges--Design and construction
St. Ignace (Mich.)
Mackinaw City (Mich.)
Mackinac Bridge (Mich.)
Date Created: 1957 (approximate)