H&H is leading the design for mechanical and electrical upgrades for the South Branch Bridge. Work includes designing the replacement of electrical cables, transformers, switchboards, and other associated electrical upgrades. The bridge has eight counterweight sheaves. Each sheave carries 16 two-and-a-quarter inch diameter ropes.
There are also eight uphaul and eight downhaul one and one-eighth-inch diameter operating ropes that wind on four operating drums located outside the machinery house on the lift span. Several idler sheaves support the operating ropes.
When H&H designed the bridge in 1914, its 1,500-ton main span was the heaviest of any vertical lift bridge in the United States. The bridge is the only vertical-lift bridge across the Chicago River and carries two railroad tracks.
