Until relatively recently, this was a swing span bridge. The swing span was removed and a lift span was put in its place. A lift span is much safer since the navigation path through the bridge is twice as wide. The span at Beardstown is normally in the up position except when a train is using the bridge. This minimizes the impact to river traffic. The lift span is operated remotely rather than having an operator on site.
The lift span was built in an interesting way. First, the piers at each end of the swing span were beefed up and widened. The lift towers were built along side and above the rail line. When the time came for the switch-over, the lift cables were attached to the swing span. The swing span was lifted, allowing the center pier and all the equipment that turned the bridge to be removed. The bridge was now a lift span, using the same truss from the swing span bridge.