UP Montrose Avenue Bridge (Irving Park)

View an article describing the design of this bridge

Located in the Irving Park neighborhood of Chicago, this concrete encased beam bridge carries the Metra Union Pacific Northwest Line over Montrose Avenue. In the late 19th Century, the numerous grade crossings throughout the city represented a hazard to the general public. In response, the City of Chicago passed numerous ordinances, requiring the elevation of freight railroads within city limits. By the 1910s, many of the major railroads within the city had been elevated. At street crossings, subways were constructed to carry railroads over the roadway. An ordinance was passed on December 29, 1913, requiring the elevation of the Chicago & North Western Railway line between a previous track elevation project at Kostner Avenue and Foster Avenue. With the requirements, the city allowed for a lenient completion date of July 1st, 1927. Work did not begin until 1916, with the majority of the construction completed in 1917. The entire project was finished by early 1918. Typical of 20th Century track elevations, the line was constructed with concrete retaining walls, and was generally constructed for three tracks.

The bridge at Montrose Avenue uses a typical design for this track elevation project, with two concrete encased beam spans, approached by a slab span on either end. The main spans of the bridge are 40 feet in length, while the approach spans of the bridge are 28 feet in length. The entire bridge is set onto concrete substructures, and the bridge runs at a heavy skew. The piers of the bridge utilize a typical design for the era, utilizing concrete columns connected by arches. This particular design was standard for most railroads throughout the United States, and provided a decorative aesthetic to bridges in urban areas. Designed by C&NW bridge engineer William H. Finley, the main spans of the bridge use concrete encased beam spans, which were constructed offsite. These spans concentrate the loading in the internal steel beams, while the main function of the concrete is to protect the steel structure. The approach spans are constructed monlithically with the abutments, which was an innovative design at the time of construction. Concrete walkways are cantilevered from both faces of the bridge, and the structure was originally constructed for six tracks. Overall, the bridge appears to remain in fair condition, with some minor deterioration noted on the substructures. However, the superstructure appears to be in better condition than similar bridges of a similar age, with very little deterioration noted. Today, the bridge continues to carry four tracks. The author has ranked the bridge as being locally significant, due to the common design.