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Once a common feature where a railroad crossed a river, a swing bridge allowed steamboat traffic to pass where riverbanks were too low for a bridge to be built high enough for boat clearance. The bridge, built by the Houston and Great Northern Railroad, is a steel Pratt Truss structure 150 feet in length and cantilevered from a massive pillar in the middle of the river. A giant gear on top of the pillar, which was connected to a motor, rotated the bridge’s arms to clear the river channel for boat traffic. The bridge was operated only two times before it was welded in place in 1925 following a flood. The Trinity River Swing Bridge is the last bridge of this type in Texas still in place.