South St. Paul Swing Bridge

Through Truss Swing Bridge over Mississippi River
South Saint Paul, Ramsey County, Minnesota
South Saint Paul, Dakota County, Minnesota

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Name South St. Paul Swing Bridge
Built By St. Paul Bridge and Terminal Railway
Contractor (1910 Truss/West Approach) American Bridge Company of New York
Contractor (East Approach) Wisconsin Bridge & Iron Company of Milwaukee
Contractor (Swing Span) Unknown
Currently Owned By Union Pacific Railroad
Length 1,277 Feet Total, 399 Foot Main Span
Width 1 Track
Height Above Ground 15 Feet (Estimated)
Superstructure Type Warren Through Truss, Pratt Through Truss and Deck Girder
Substructure Type Concrete
Date Built 1910, East Approach Rebuilt 1925; Swing Span Rebuilt 1956
Traffic Count 20 Trains/Day (Estimated)
Current Status In Use
UP Bridge Number 349.76
Significance Moderate Significance
In 1885, the Minnesota and Northwestern Railroad began construction on 129 miles of railroad between St. Paul, Minnesota and Manly, Iowa.
In 1887, this line became a part of the Chicago, St. Paul and Kansas City Railway. By 1893, the CStP&KC was merged into the Chicago Great Western Railway.
CGW had a moderate amount of trackage throughout Minnesota, Iowa, Missouri and Illinois. The CGW linked Kansas City, Des Moines, Chicago and St. Paul at the time of creation.
In 1901, the Mason City & Fort Dodge Railway continued construction on the route with a 10 mile line into Mason City, which the Rock Island would later use as well.
In 1902, 47 miles of railroad between Manly and Hayfield, Minnesota were sold back to the Mason City & Fort Dodge.
While the CGW and MC&FD remained separate on paper, the two were closely tied. By 1940, the CGW took full ownership of the MC&FD.

The CGW was never a strong railroad. As a result, it was purchased by the Chicago & North Western Railway in 1968. This segment of line remained somewhat important for the C&NW, particularly north of Hayfield.
The first abandonment consisted of a short segment of line between Waltham and Austin, Minnesota in 1977.
However, the parallel Rock Island route was a straighter and all around better route. When the Rock Island fell bankrupt, the C&NW purchased the Saint Paul-Kansas City line, rendering this route,as well as the parallel Minneapolis & St. Louis route, useless.
By 1981, the route between Manly and Austin would be abandoned. In 1982, the route between Randolph and Waltham would follow.
The final abandonment came in 1984, and included a section between Roseport and Randolph.
Currently, the Manly-Mason City and St. Paul-Roseport sections are operated as the Union Pacific Albert Lea Subdivision.

This swing bridge crosses the Mississippi River near Pigs Eye Island in South Saint Paul.
Originally built in 1910, the bridge has seen some alterations since original construction.
When originally built, the bridge consisted of a large through truss swing span, and a 7-panel, pin connected Pratt Through Truss. In addition, the bridge also had a number of deck girder approaches. The entire structure was set onto concrete substructures.
The bridge was upgraded in 1925, 1956 and 1982. Authorization for Expenditure (AFE) reports give a 1956 date for the rebuilding of the swing span, which had been undercut by flooding.
It is unknown why the original swing span was replaced, although flooding or a derailment are possibilities. Other alterations have occurred to the bridge, including the replacement of a pier damaged by a boat in 2017.
Currently, the bridge remains in service. Overall, it appears to be in good condition.

The author has ranked this bridge as being moderately significant, due to the truss design. A higher rating was withheld due to the lack of a historic swing span.
The photo above is an overview. The photo below is the portal on the approach truss. Unfortunately, the east approach is not currently accessible.

Mississippi River Railroad Bridges
Upstream Robert Street Lift Bridge
Downstream Rock Island Swing Bridge

These Pictures Start at Varying Points in the Series

Detail Photos


Source Type


Build Date "Climbing the Mississippi River Bridge by Bridge, Volume Two: Minnesota" by Mary Costello
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

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