While Chicago has many historic bridges, this structure is one of the top.
Bobtail swing bridges are extremely rare, and Chicago has a pair. Both structures were built by the Milwaukee Road, which also built bobtail swing bridges in Milwaukee, Sauk City and Saint Paul.
This bridge is another unique structure along the Milwaukee Road. A bobtail swing bridge is asymmetrical, and uses a large concrete counterweight on the smaller leaf.
The bridge uses 210 tons of structural steel, but also uses 140 tons of concrete for the counterweight.
The bridge is a 7-Panel, pin connected Pratt Through Truss with large counterweight on the south end. The south leaf has 6 panels, while the north only has one. The bridge uses concrete substructures, and a standard X frame bracing.
This bridge replaced an originally wooden swing bridge, which had outlived its useful service.
In 2009, the bridge was rehabilitated. Given the low traffic rates on the bridge, the structure was converted to a rail and trail bridge.
New fences were added, and the rollers rehabilitated. In addition, interpretive sign was added, the counterweight was reconstructed, and the steel was repainted.
Overall, the bridge appears to be in great condition. It is unknown if the bridge will continue to serve railroad traffic for years to come, or if it will become a full-time trail.
The author has ranked this bridge as being highly significant, due to the unique design.
HAER Documentation can be found here
Drawings can be found here
Thank you to Historicbridges.org for the links!
The photo above is an overview looking north, as a storm came into Chicago.
| Upstream | Bloomingdale Line Swing Bridge |
| Downstream | MILW Kinzie Street Swing Bridge |