Sauk City Rail Bridge (West)

Lost Pratt Pony Truss Bridge over Wisconsin River
Sauk City, Sauk County, Wisconsin
Rural Dane County, Wisconsin

Click the Photo Above to See All Photos of This Bridge!
Name Sauk City Rail Bridge (West)
Built By Chicago, Milwaukee & St. Paul Railway
Contractor (Swing Span) Lassig Bridge & Iron Works of Chicago
Contractor (Girder Spans) Wisconsin Bridge & Iron Company of Milwaukee
Currently Owned By State of Wisconsin
Length 455 Feet Total, 120 Foot Truss Spans
Width 1 Track
Height Above Ground 25 Feet (Estimated)
Superstructure Type Pratt Pony Truss, Deck Girder and Through Girder
Substructure Type Concrete and Timber Pile
Date Erected 1910 and 1943
Date Fabricated (Swing Span) 1892
Original Location (Swing Span) Bridge #D-562; Portage, Wisconsin
Date Fabricated (Trusses) Ca. 1899
Original Location (Trusses) Unknown
Date Fabricated (Girders) 1897
Original Location (Girders) Bridge #Z-1586; Chautauqua, Iowa
Date Removed 2002 and 2018
Traffic Count 0 Trains/Day (Bridge is Mostly Removed)
Current Status Mostly Removed
MILW Bridge Number B-428
Significance Regional Significance
In 1881, the Chicago, Milwaukee & St. Paul Railway built a short branch line from their existing line at Mazomanie, Wisconsin northwards towards Prairie Du Sac.
The line was a branch line meant to serve the river towns of Sauk City and Prairie Du Sac.
The CM&StP became the Chicago, Milwaukee, St. Paul & Pacific in 1915, with the nickname of the Milwaukee Road.
In 1941, the line was extended to serve the Badger Ammunitions Plant north of Prairie Du Sac.

The line was purchased in 1982 from the Milwaukee Road by the Wisconsin Western Railroad, which would eventually be purchased in 1985 by the Wisconsin & Calument, a short line railroad which operated many other lines in the Madison Area.
The WICT was purchased by Wisconsin & Southern in 1992, who operated this line until March 2002, when the northern truss span crossing the Wisconsin River began to shift.
The maintenance to stabilize the bridge failed, and the span was blown up.
A similar situation happened in late 2016, after trail talks finally succeeded. The remainder of the bridge was removed, and a new bridge will be constructed for trail use.

Located in Sauk City, this mostly demolished bridge once crossed the main channel of the Wisconsin River.
Originally built in the 1880s as a wooden truss swing bridge, this route has served as a spur into Sauk City.
In 1910, a secondhand pin connected Whipple Through Truss bridge was relocated from Sabula, Iowa, and the remainder of the bridge was also reconstructed.
In addition to the Whipple Truss, a 123' counterbalanced deck plate girder swing span was relocated from Bridge #D-562 (Portage Canal; Portage, Wisconsin). This girder span was originally fabricated in 1892.
On the east end, two girders would be relocated from Bridge #Z-1586; Chautauqua, Iowa. These spans were originally fabricated in 1897.

Historic Photo
Historic photo of the bridge

At this time, the bridge was still connected to a long structure over the back channel.
During World War II, an ammunition manufacturing facility opened north of Prairie du Sac. As a result, the 1881 vintage Whipple Through Truss would be replaced by a pair of secondhand pony truss spans.
These two pin connected Pratt Through Truss spans were likely fabricated by Lassig Bridge & Iron Works in approximately 1899, at unknown locations.
The relocation of these two spans gave the bridge its final configuration. From east to west:

1-123' Deck Girder draw span (Built 1892 at Bridge #D-562; Moved here 1910)
1-97'6" Pratt Pony Truss (Built ca. 1900 at an unknown location; Moved here 1942)
1-112'10" Pratt Pony Truss (Built ca. 1900 at an unknown location; Moved here 1942)
2-55' Type "B" Through Girders (Built 1897 at Bridge #Z-1586; Chautauqua, Iowa; Moved here 1910)

The substructures consisted of concrete piers, except a timber pier between the two trusses.
Unfortunately, in 2002, pier #2 became undermined. A controlled explosion removed the failing pier and the western truss span.
The bridge remained out of service until 2016, when plans were made to repair the bridge and convert it to trail use. However, in 2017, pier #4 began to shift several feet, similar to how pier #2 did. As a result, the other pony truss and two through girders were removed in 2018.
After the removal, the bridge has only its deck girder swing span left, which has not operated in many decades. A new trail bridge is proposed, which will remove the remaining historic portions of this bridge.

The author has ranked this bridge as being regionally significant, due to the extensive relocation history of this bridge.
The photo above is an overview in early 2018, before the bridge was demolished.

Wisconsin River Railroad Bridges
Upstream Merrimac Rail Bridge
East Channel Sauk City Rail Bridge (East)
Downstream Spring Green Rail Bridge


Source Type


Bridge History Milwaukee Road Archives at the Milwaukee Central Library
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

Widget is loading comments...

© Copyright 2010- John Marvig and Contributors. All Rights Reserved