Friday, January 16, 2009

Photo Fridays

Gears under Chicago Avenue Bridge
Chicago, IL

The Chicago River has 38 movable bridges of several different types, one of which is a bascule bridge. From Wikipedia: "A bascule bridge is a moveable bridge with a counterweight that continuously balances the span, or "leaf," throughout the entire upward swing in providing clearance for boat traffic." The gears are part of the mechanism used to give controlled movement once the span starts swinging up or down. Pretty impressive!

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