CPKC Pittsburgh Avenue Bridge (Milwaukee)

Located on the south side of downtown Milwaukee, this through plate girder bridge carries the former Chicago, Milwaukee, St. Paul & Pacific Railroad (Milwaukee Road) mainline over Pittsburgh Avenue. In the early 20th Century, the City of Milwaukee ordered grade separations at many of the busy railroad lines throughout the City. Inspired by track elevation projects in Chicago, early ordinances were passed for both track elevation and depression in approximately 1904, and the ordinances later expanded to include several other lines throughout the City. In approximately 1914, an ordinance was passed requiring the elevation of the Milwaukee Road mainline from a point near Greenfield Avenue to downtown Milwaukee. Similar to many other grade separation ordinances throughout the United States, the City of Milwaukee dictated the dimensions required for each subway. Work on the elevation project began in 1915, and the project was completed sometime in 1916. The subway at Pittsburgh Avenue (then Reed Street) was completed late in the 1916 construction season.

Currently, the bridge consists of two 24-foot and two 15-foot through plate girder spans, set onto concrete abutments and steel bent piers. Typical of through plate girder spans used for 20th Century grade separations, the floor is constructed using a trough floor design. This design consists of numerous transverse beams/channels, which are filled with asphalt cement and ballast. This design helped to deaden noise and reduce maintenance. The piers are constructed of three large steel columns, connected by a lattice beam at the top and rounded bracing beneath. Wisconsin Bridge & Iron Company fabricated the steel components of the bridge, while labor employed by the Milwaukee Road Bridge & Building Department completed the concrete portions of the bridge. Through plate girder spans were commonly used by railroads, as they were durable and easy to construct. The trough floor design was a popular alteration to the through girder design for this application.Currently, both tracks of the bridge remain in use. Overall, the bridge appears to be in fair to poor condition, with some deterioration noted to the structure. A number of minor repairs were made to the structure in the late 2010s. The author has ranked the bridge as being locally significant, due to the common design.