Spring Green Rail Bridge

Pratt Through Truss Swing Bridge over Wisconsin River
Spring Green, Sauk County, Wisconsin
near Arena, Iowa County, Wisconsin

Click the Photo Above to See All Photos of This Bridge!
Name Spring Green Rail Bridge
Built By Chicago, Milwaukee, St. Paul & Pacific Railway
Contractor (Truss Spans) Lassig Bridge & Iron Works of Chicago
Contractor (Through Girder Spans) American Bridge Company of New York
Currently Owned By State of Wisconsin
Currently Operated By Wisconsin & Southern Railroad
Length 1,920 Feet Total, 210 Foot Main Span
Width 1 Track
Height Above Ground 25 Feet (Estimated)
Superstructure Type Pratt Through Truss, Through Girder, Deck Girder and I-Beam
Substructure Type Stone Masonry, Concrete and Steel Pile
Date Erected 1899, Rebuilt 1927, 1929 and 1942
Date Fabricated (Approach Trusses) 1895
Original Location (Trusses) Unknown
Date Fabricated (Girders) Unknown
Traffic Count 2 Trains/Day (Estimated)
Current Status In Use
MILW Bridge Number B-256
Significance Regional Significance
In 1850, the Milwaukee and Mississippi Railroad began construction of a line charted to connect 196 miles between Milwaukee, Wisconsin and Prairie Du Chein, Wisconsin.
By the end of the year, the railroad reached from Milwaukee to Elm Grove, and went through Wausautosa. The following year, an extension would be made another 10 miles to Waukesha.
In 1852 and 1853, the railroad built another 42 miles of track to Milton, and 18 miles from Milton to Stoughton, respectively.
Between 1854 and 1856, the railroad was extended through Madison, to Boscobel, an addition of 86 miles.
In 1858, the railroad completed to Prarie du Chein, and opened the opportunity for expansion westwards.
With a successful and mainline completed and fully operational, the M&M was purchased by the Milwaukee and Prairie du Chen Railway in 1861. In turn, the M&PdC was purchased by the Milwaukee and St. Paul Railway in 1867.
The M&StL operated numerous railroads throughout Wisconsin, and was merged into the Chicago, Milwaukee & St. Paul Railway in 1874. Known as the Milwaukee Road, the system expanded rapidly over the upper midwest.
The CM&StP later became known as the Chicago, Milwaukee St. Paul & Pacific Railway in 1915, after completing a transcontinental route.

This route would quickly be downgraded to a secondary mainline, after other routes became preferable.
While this was one of the first railroads completed, the route was sold in 1980 to the State of Wisconsin, who picked Wisconsin & Southern to operate the route. This arrangement is still ongoing in 2018.

Another massive bridge crosses the Wisconsin River near Spring Green.
Built of a mish-mash of spans, the bridge is one of the longest and most unusual over the Wisconsin River.
The previous bridge here used several 1886 truss spans, one of which was known to have been moved to Dunnville, Wisconsin. The bridge was altered in 1927, 1928, 1942 and 2017, putting it in the current configuration, which is as follows:

30 span steel stringer (built 2017)
2-112'6" 5-panel, pin connected Pratt through trusses (built 1895 and moved here 1927)
205' pin connected Pratt through truss swing span (built 1899, strengthened 1937)
2-52'6" through plate girders (built 1927)
1-68' deck plate girder (built 1942)
2-70' deck plate girders (built 1942)
1-75' deck plate girder (built 1927)
1-60' deck plate girder (built 1927)
4 span steel stringer (built 2017)

The substructures on this bridge are constructed of stone, concrete and steel piles.
The two 1895 trusses were fabricated by Lassig Bridge & Iron Works at an unknown location. Identical spans were reused at Merrill, Wisconsin in 1929 and at Jefferson, Iowa in 1930. It is likely that these spans are all related, possibly from the same line.
The 75' and 60' girders each had blueprints at the Milwaukee Road Archives at the Milwaukee Public Library. It is unknown if these are the same spans. The blueprints indicate that the 75' deck girder was altered from an 80' deck girder originally built at Bridge #Z-284 (Kilbuck Creek; west of Monroe Center, Illinois) in 1883, and moved here 1905. The 60' deck girder bridge was converted to a skew span as well, and was originally built at Bridge #I-1090 (Skunk River; Rubio, Iowa) in 1901 before being moved here in 1905. It is unknown if the 1928 rebuild of these spans reused the older steel.
In 2017, original timber west approach and east jump spans would be replaced by modern I-Beam spans on steel piles. These upgrades have brought the bridge to its present configuration.
Overall, the bridge appears to be in fair condition. The trusses are exceptionally light for the traffic this bridge carries, and may be a replacement candidate in the coming years. The swing span has not operated in many years.

The author has ranked this bridge as being regionally significant, due to the unique design and history.
The photo above is an overview from the east bank. The photo below is a photo of a plaque.

Wisconsin River Railroad Bridges
Upstream Sauk City Bridge (West)
Upstream East Channel Sauk City Bridge (East)
Downstream Lone Rock Rail Bridge

Detail Photos from June 2018


Source Type


Build Dates (Swing Span) Milwaukee Road Archives at the Milwaukee Central Library
Build Date (Approach Trusses) Lassig Bridge & Iron Works plaque
Build Date (Girder Spans) Milwaukee Road Archives at the Milwaukee Central Library
Contractor (All Truss Spans) Lassig Bridge & Iron Works plaque
Contractor (Through Girder Spans) Missing American Bridge Company plaque
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

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