Janesville Rail Bridge

Double Intersection Warren Deck Truss Bridge over Rock River
Janesville, Rock County, Wisconsin

Click the Photo Above to See All Photos of This Bridge!
Name Janesville Rail Bridge
Built By Chicago & North Western Railway
Contractor (1896 Trusses) Lassig Bridge & Iron Works of Chicago
Contractor (1907 Substructure) Bates & Rogers Construction Company of Chicago
Contractor (1908 Superstructure) American Bridge Company of New York
Currently Owned By Union Pacific Railroad
Length 720 Feet Total, 150 Foot Largest Span
Width 2 Tracks, 1 In Use
Height Above Ground 45 Feet (Estimated)
Superstructure Type Double Intersection Warren Deck Truss and Girder
Substructure Type Stone Masonry and Concrete
Date Built 1896, Rebuilt 1907/1908
Traffic Count 2 Trains/Day (Estimated)
Current Status In Use
Historic C&NW Bridge Number W-128
UP Bridge Number 90.52
Significance Regional Significance
Documentation Date June 2014
A brief history of the Union Pacific Harvard Subdivision:


One of the most unique bridges in southern Wisconsin, this massive deck truss bridge crosses the Rock River.
Originally built in 1896 as a single track bridge, the bridge was widened in 1908. Typically, widening steel bridges consisted of adding additional substructures, and adding new spans.
With a large bridge as this, it gets much more complex to widen a bridge. It appears new stone and concrete substructures were added, and a new southbound track constructed. The existing northbound track reused the same substructures, although the new spans were slightly longer to make up for the 1880s vintage parapet abutments.
Currently, the bridge consists of four large riveted Double Intersection Warren Deck Trusses. Parallel but separate spans can be seen for the bridge. These spans, despite being built 12 years apart, are extremely similar. Only minor differences can be noted in the design.
However, the southbound span consists of a deck girder spans on the north end, to balance out the older parapet abutment the northbound span uses. In addition, a through girder span crosses the former Milwaukee Road route. This span was added in 1908, likely to replace a span of similar construction.
The piers for the bridge are all cut ashlar stone, and the appear to have been originally built in 1896, and widened in 1908. The abutments of the bridge are a combination of concrete and stone.
Overall, the bridge appears to remain in good condition. The northbound track has since been removed, and traffic uses only the southbound span now.

Historic Photo
Historic photo of the bridge

The author has ranked this bridge as being regionally significant, due to the large scale example of this design.
The photo above is an overview. The bridge can be accessed from US-51, just downstream.

Rock River Railroad Bridges
Upstream Jeffris Park Trail Bridge
Downstream WSOR Rock River Bridge (S)

Detail Photos from June, 2014


Source Type


Build Date (1896 Spans) Chicago & North Western Railway Historical Society
Build Dates (1908 Spans) American Bridge Company plaque
Contractor (1896 Spans) Chicago & North Western Railway Historical Society
Superstructure Contractor (1908 Spans) American Bridge Company plaque
Substructure Contractor (1908 Spans) Bates & Rogers Construction Company plaque
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

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