CN Chicago Avenue Bridge (River Forest)

Name	CN Chicago Avenue Bridge (River Forest) Soo Line Railroad Bridge #11.91
Built By	Minneapolis, St. Paul & Sault Ste. Marie Railroad
Currently Owned By	Canadian National Railway
Contractor	Unknown
Length	82 Feet Total, 42 Foot Main Span
Width	2 Tracks, 1 In Use
Height Above Ground	11 Feet 9 Inches
Superstructure Design	Through Plate Girder
Substructure Design	Concrete and Steel Bent
Date Built	c. 1910
Traffic Count	5 Trains/Day (Estimated)
Current Status	In Use
Soo Line Railroad Bridge Number	11.91
Significance	Local Significance
Documentation Date	11/18/2023

In 1882, the Milwaukee and Lake Winnebago Railroad (M&LW) constructed 64 miles of new railroad between Neenah, Wisconsin and Germantown, Wisconsin. Between 1885 and 1886, the Chicago, Wisconsin and Minnesota Railroad (CW&M) would construct an additional 66 miles of new railroad between Germantown and the Illinois/Wisconsin State Line, and the Chicago and Wisconsin Railroad Company (C&W) would construct an additional 42 miles of railroad to near Chicago at the same time. Outside of Chicago, the line connected to the Baltimore & Ohio Chicago Terminal Railroad (B&OCT) near Forest Park. The line would be leased and operated by other railroads, including the Northern Pacific Railway between 1890 and 1893, and the Wisconsin Central Railroad from 1893 to 1899. In 1899, the railroads would be consolidated to form the Wisconsin Central Railway (WC). This line formed the backbone of the WC, which operated a mainline extending from Chicago to Minneapolis. Except for short segments near Forest Park and River Forest, much of this line was single tracked.

In 1909, the WC would be leased by the Minneapolis, St. Paul & Sault Ste. Marie Railway (Soo Line), which itself was controlled by the Canadian Pacific Railway (CP). The Soo Line had constructed a large network of railroads, connecting the Upper Midwest with Canadian Railroads. Throughout the 20th Century, the line remained a critical component of the Soo Line system. By 1961, the Soo Line would be merged with other CP subsidiaries Duluth, South Shore & Atlantic Railroad and Wisconsin Central Railroad to form Soo Line Railroad, a company controlled by CP. In 1984, the Soo Line would be reorganized as the Soo Line Corporation, and the railroad would be fully merged into CP in 1990. After the Soo Line acquired the Milwaukee Road in 1986, this route became less important, as the Milwaukee Road purchase provided Soo with additional connections between Chicago and Minneapolis. In 1987, the route would be sold to Wisconsin Central, Ltd. Known as the "new" Wisconsin Central, the railroad acquired several excess rail lines from the Soo Line and Chicago & North Western Railway, before being acquired as the American subsidiary of Canadian National Railway (CN) in 2001. Today, CN operates this line as the Waukesha Subdivision.

Located in River Forest, this through plate girder bridge once carried the Soo Line over Chicago Avenue. Built in approximately 1910 as part of a larger track elevation project, the bridge consists of a 42-foot and two 20-foot through plate girder spans, set onto steel bents and concrete abutments. The bridge was originally constructed to carry two tracks, but currently carries only a single track. The ballast channel of the bridge is constructed using a concrete deck, poured around the floorbeams of the structure. One other bridge along the track elevation project used this design, and the girder utilizes a typical rounded and tapered end. Through plate girder spans like this were often used to cross city streets in urban areas, as the design was durable and easy to construct. Ballast decks were preferred on these structures, as they reduced hazards to roadway users below and were more cost effective to maintain. The bridge appears to have received repairs and been painted in the 2000s. At the time of documentation, the bridge appeared to be in poor condition, with extensive section loss noted throughout the piers. A concrete encasement was added to the lower half of the piers in August 2024. The author has ranked this bridge as being locally significant, due to the common design.

CN Chicago Avenue Bridge (River Forest)

River Forest, Cook County, Illinois