Click the photo to view the full-size version
| Name | Northbrook Railroad Crossing Chicago & North Western Railway Bridge #864 |
| Built By | Chicago & North Western Railway |
| Currently Owned By | Union Pacific Railroad |
| Superstructure Contractor | Fort Pitt Bridge Works of Pittsburgh, Pennsylvania |
| Substructure Contractor | Company Forces |
| Length | 140 Feet Total |
| Width | 2 Tracks |
| Height Above Ground | 25 Feet (Estimated) |
| Superstructure Design | Quadrangular Lattice Through Truss |
| Substructure Design | Concrete |
| Date Built | 1912 |
| Traffic Count | 25 Trains/Day (Estimated) |
| Current Status | In Use |
| Chicago & North Western Railway Bridge Number | 864 |
| Union Pacific Railroad Bridge Number | 18.15 |
| Significance | Moderate Significance |
| Documentation Date | 7/8/2018 |
In the late 19th Century, Chicago grew to the prominent railroad hub in
the central United States. Chicago also served as the dividing point
between the railroads operating in the east and railroads operating in
the Midwest. The Chicago & North Western Railway (C&NW) had constructed a network of railroad lines, radiating north and west from Chicago. Until a freight bypass was constructed in 1889, all freight traffic from Wisconsin was required to enter downtown Chicago. In the early 20th Century, the C&NW invested heavily in rebuilding existing lines, opening new lines and improving operations. In 1903, subsidiary Chicago Northern Railway Company (CNR) constructed 22 miles of double track railroad between the Mayfair-Evanston freight bypass at River Junction (present day Bryn Mawr Avenue), northwards into Lake County, before turning east to reach the existing C&NW mainline at Lake Bluff, Illinois. Further double track extensions came in 1905-1906, when the Chicago & State Line Railway constructed 16 miles between Tower KO (Lake Forest) and the Wisconsin state line; and the Milwaukee & State Line Railway constructed 34 miles between the state line and St. Francis, Wisconsin; where it joined the existing C&NW mainline between Chicago and Milwaukee. Also in 1908, the C&NW constructed a short 2.3 mile double track line between St. Francis, Wisconsin and the existing C&NW mainline between Milwaukee and Madison at Chase (South Milwaukee). The two railroads were formally consolidated into the C&NW in 1909.
Another double track line was constructed beginning in 1911. Subsidiary Des Plaines Valley Railway (DPV), constructed 11 miles of railroad connecting the Proviso Yard, located east of Elmhurst, to the Wisconsin Division mainline near Des Plaines. The following year, an additional 10 miles were completed to Valley, located in present-day Northbrook. In addition, the Milwaukee, Sparta & North Western Railway (MS&NW) constructed a short 8-mile double track line between the existing C&NW mainlines at Butler, Wisconsin and West Allis, Wisconsin in 1911. It is believed that the C&NW double tracked the existing line between West Allis and Chase at this time. The MS&NW was formally merged into the merged into the C&NW in 1912, followed by the DPV in 1913. The route from St. Francis to Proviso formed a second freight bypass of Chicago, allowing freight from Wisconsin to reach the hump yard at Proviso. This cutoff became a critical portion of the C&NW network, providing a bypass of Chicago and a main way to reach the Proviso Yard from all three principal mainlines of the railroad. The line between Butler and West Allis provided a bypass of Milwaukee, improving operations in the area.
The C&NW would become a prominent railroad in the Midwest,
eventually building a system over 11,000 miles long. Portions of this route were relocated in 1954 to accommodate an expansion of O'Hare International Airport. Much of the second track between Gurnee and St. Francis would be removed in 1960. By 1968, deteriorated track conditions between Dempster Street and Valley resulted in the C&NW acquiring and operating the parallel Chicago, North Shore & Milwaukee Railway trackage. In 1988, the C&NW abandoned the tracks between Oakton Street in Skokie and River Junction. In 1995, the
C&NW would be purchased by the Union Pacific Railroad. UP abandoned the Skokie to Valley segment in 2004. Today, UP continues to operate the Milwaukee Subdivision between Proviso and Butler, and it continues to provide a critical freight route around Chicago.
Located near Willow Road in Northbrook, this large truss bridge carries the former C&NW across the former Milwaukee Road, now owned by CPKC. During construction of the line, a temporary bridge was erected at this location. This bridge utilized a 30-foot secondhand girder span, and timber pile trestle spans. As much of the Des Plaines Valley Railway was constructed on a large fill, much of the line was constructed by constructing temporary trestles, and filling them with earth. In 1912, a permanent bridge would be constructed at this location. The bridge consists of a double track 140-foot riveted quadrangular lattice through truss span, set onto concrete abutments. The truss span utilizes a ballast deck, which is integral to the structure, and the truss runs at a skew. The truss span was fabricated by the Fort Pitt Bridge Works, while the abutments were constructed by railroad forces.
The quadrangular lattice through truss design was the standard truss bridge design of the C&NW from the late 1870s through the 1920s. While other railroads preferred more traditional truss designs, the C&NW used this design near exclusively for nearly 50 years. Dozens of examples of C&NW quadrangular lattice spans continue to exist throughout the Midwest. The design offered a resilient design, capable of withstanding derailments. This particular span is representative of a later generation of this design, utilizing solid members, an M-frame portal and a ballast deck. The ballast channel on this bridge consists of steel plates, set onto the floor beams. The sides of the channel are made up by the lower chords of the bridge. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked the bridge as being moderately significant, due to the truss design.
Citations
| Builder and build date | Chicago & North Western Valuation Notes at the Chicago & North Western Historical Society Archives |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |