Kate Shelley High Bridge

Landmark Deck Truss Bridge over Des Moines River
West of Boone, Boone County, Iowa

Click the Photo Above to See All Photos of This Bridge!
Name Kate Shelley High Bridge
Built By Chicago & North Western Railway
Contractor (Superstructure) American Bridge Company (Lassig Branch)
Contractor (Masonry) Widell Company of Mankato, Minnesota
Engineer (Chief) E.C. Carter of Chicago
Engineer (Consulting) George S. Morison New Bedford, Massachusetts
Currently Owned By Union Pacific Railroad
Length 2,685 Feet Total, 300 Foot Main Span
Width 2 Tracks
Height Above Ground 185 Feet Total
Superstructure Type Baltimore Deck Truss and Deck Girder
Substructure Type Steel Tower and Stone Masonry
Date Built 1899 to 1901
Date Rehabilitated Winter 2001
Date Bypassed August 2009
Traffic Count 0 Trains/Day (Bridge Is Closed)
Current Status Closed to All Traffic
C&NW Bridge Number 615
Significance National Significance
Documentation Date July 2012 (Photo 1); March 2013 (Photos 2-10, 23-28); October 2017 (Photos 11-20, 29-35); January 2018 (Photos 21-23, 36-46)
A brief history of the Chicago & North Western Iowa Division mainline, now part of the Overland Route:


The most astonishing accomplishment of engineering the State of Iowa ever received was the construction of the Boone Viaduct from 1899 to 1901.
The structure was constructed by American Bridge Company of New York, after Union Bridge Company, the original contract holder, became part of American Bridge Company.
Engineers included E.C. Carter of Chicago, Illinois as Chief Engineer; and George S. Morison of New Bedford, Massachusetts as Consulting Engineer.
Rising a staggering 185 feet above the water of the Des Moines River, the 2,685 foot long Baltimore Deck Truss and Deck Girder is the cornerstone of the former Chicago & North Western system, rivaled only by its successor upstream, and the Fort Dodge High Bridge.

Not only is the bridge one of the most significant in Iowa, it also is the most well known. This structure, and its Successor are considered to be the largest double tracked railroad bridges in the world.
The bridge is set on stone substructures. Cut stone blocks make up the foundations of the towers, and quarried stone from Mankato, Minnesota makes up the abutments.
Steel Caissons, which go nearly 40 feet below the surface support the towers which support the main span.
The steel towers consist of simple steel rods, tied together with X-Frame bracings to hold the deck girders, which alternate lengths.
The main span is a 5 panel, pin connected Baltimore Deck Truss, supported on heavier towers.

The bridge was named for Kate Shelley, a heroine who ran down the railroad tracks on a stormy July 1881 night near Moingona.
The Bridge Over Honey Creek, near the Shelley Household, collapsed under the weight of a train, and Shelley knew that another train would be coming soon.
She ran over a mile, and crossed the Des Moines River Bridge in the dead of night to save the train.
In saving the train, she quickly became a national hero. Because of this, when the new alignment opened in 1901, and included the Boone Viaduct, Shelley's name quickly became attached.

American Bridge Company did an extensive rehabilitation of the center truss in 2001, although it became clear the span would not be able to serve the usefulness of a heavy mainline any longer.
In 2007, a new high bridge would be built to bypass the old one, which had become way too spindly for the railroads liking, and more than one train had fallen off.
The new bridge consists of 26 deck girder spans, and precast concrete approaches on either side.
Today, the bridge sits dormant downstream of its successor. It is listed on the National Register of Historic Places. In an emergency, the old bridge could become active again within hours, and still is maintained and holds tracks on the deck.

As stated in a Report of the Historic American Engineering Record:
"The Boone Viaduct has an approximately 300' long, 60' deep deck channel span composed of two deck Pratt trusses with the panels divided into five sub-divided panels by means of sub-verticals which support the middles of the top-chord sections.
There are four lines of plate girders, two under each track, of a uniform depth of 7'. Beginning on the east end there are two 75' plate-girder spans on a rocker bent; then six 45' plate girder spans, alternating with six 75' plate-girder spans. The 45' plate-girder spans carried on and form the tops of towers consisting of four columns each, rigidly braced together on all sides. The 75' plate-girders span the opening between consecutive towers.
This bridge is one of the last projects of noted bridge engineer George Morison, who died two years after the structure was built. The bridge was the longest and heaviest viaduct of its time, and may be the longest extant double-track railroad viaduct in the world. It is listed in the National Register of Historic Places.
This document was prepared as part of the Iowa Historic Bridges Recording Project performed during the Summer of 1995 by the Historic American Engineering Record (HAER). The project was sponsored by the Iowa Department of Transportation. (IDOT)."

The photo above is an overview from March 2013, the photo in the middle is a caisson of the bridge, and the photo below is an overview of construction operations in 1900 (C&NWHS).
For the photos below, Photos 34 Through 42 were donated by the Chicago & North Western Historical Society. 43 Through 58 are Historical American Engineering Record Photos from 1995.
The author has ranked this bridge as being nationally significant, due to the unique design and landmark status.

Des Moines River Railroad Bridges
Upstream New Kate Shelley High Bridge
Downstream Moingona Railroad Bridge

These Pictures Start at varying points in the Series
Detail Photos

Historical and Historic American Engineering Record Photos


Source Type


Build Date Chicago & North Western Railway Historical Society Archives
Contractors and Engineers Chicago & North Western Railway Historical Society Archives
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

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