CN Boone River Bridge

Webster City, Hamilton County, Iowa

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Photo showing previous bridge during 1903 raising

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Name	CN Boone River Bridge Illinois Central Railroad Bridge #W354.8
Built By	Illinois Central Railroad
Currently Owned By	Canadian National Railway
Superstructure Contractor	American Bridge Company of New York
Substructure Contractor	Unknown W.D. Faus of Webster City, Iowa (1903 Reconstruction)
Length	437 Feet Total, 79 Foot Largest Spans
Width	1 Track
Height Above Ground	40 Feet (Estimated)
Superstructure Design	Deck Plate Girder
Substructure Design	Stone Masonry and Concrete
Date Built	1948
Traffic Count	3 Trains/Day (Estimated)
Current Status	In Use
Illinois Central Railroad Bridge Number	W354.8
Canadian National Railway Bridge Number	354.8
Significance	Local Significance
Documentation Date	7/22/2012; 3/26/2013; 3/28/2021

In 1857, the Dubuque and Pacific Railroad (D&P) began construction of a new mainline across central Iowa, which sought to link to the existing Illinois Central Railroad (IC) at Dubuque, Iowa. In May 1857, the first 29 miles were completed between Dubuque and Dyersville, Iowa. In March 1860, the line was completed an additional 49 miles from Dyersville to Jesup, Iowa. In 1860, the D&P was sold to the Dubuque and Sioux City Railroad (D&SC). The D&SC completed an additional 22 miles to Cedar Falls, Iowa in 1861; followed by an additional 43 miles to Iowa Falls, Iowa in 1866. By 1867, the IC had garnered interest in this line, and leased the D&SC. The following year, a bridge across the Mississippi River at Dubuque was completed to link this line and the IC line towards Freeport, Illinois. In August 1869, the Iowa Falls and Sioux City Railroad (IF&SC) completed an additional 49 miles from Iowa Falls to Fort Dodge, Iowa. In October 1870, an additional 135 miles were completed west to the Missouri River at Sioux City, Iowa. The IF&SC was also affiliated with the D&SC and IC; and was fully merged into the D&SC in 1888.

By the late 19th Century, the IC had developed and operated a sprawling railroad network in the central United States. This line served as a principal mainline for the company, connecting Chicago to the Missouri River at Sioux City. In the 20th Century, the IC had become a respected railroad, connecting several major cities in the central United States. The D&SC was fully merged into the IC in 1946. In 1972, the IC merged with the Gulf, Mobile & Ohio Railroad (GM&O) to form the Illinois Central Gulf (ICG). The entire IC system in Iowa, as well as the line between Dubuque and Chicago, were sold to the Chicago Central & Pacific Railroad (CC&P) in 1995. In 1988, the ICG was reorganized as the Illinois Central Railroad (IC). In 1996, the CC&P was repurchased by IC and in 1998, IC was purchased by the Canadian National Railway (CN). Today, CN operates the Dubuque Subdivision between Dubuque and Waterloo, Iowa; the Waterloo Subdivision between Waterloo and Fort Dodge, and the Cherokee Subdivision between Fort Dodge and Sioux City.

Located on the north side of Webster City, this large deck plate bridge carries a former Illinois Central Railroad mainline over the Boone River. This crossing has a lengthy history, dating back to when the railroad began construction Webster City in 1867. The first bridge consisted of two 125-foot covered wooden through truss spans with iron tension rods, set onto stone piers and approached by timber pile trestle spans. This bridge was periodically renewed with similar structures. In 1890-91, the bridge was heavily by adding two 136-foot, 7-panel, pin-connected Pratt through truss spans at the west end. At this time, an additional stone pier and new west abutment were constructed. These two spans were lightly constructed, with built-up members and a decorative crested portal bracing. It is believed that they were fabricated by the Pencoyd Iron Works, which completed a handful of structures for the IC in 1891. In 1900, the original wooden trusses were replaced with a 157-foot, 9-panel, pin-connected Pratt through truss span and a new concrete east abutment. This span was reportedly fabricated in 1879, and had similar features to the west spans. While the span had features similar to Union Bridge Company spans, it is unclear if this firm was responsible for fabricating the span. In 1903, a significant project was undertaken to raise the bridge and eliminate a large sag through Webster City. The bridge was raised 16 feet by adding concrete to the tops of the existing stonework substructures and encasing the remaining stone in concrete. By the 1940s, the truss span was no longer suitable for heavy locomotives, and plans were made to replace the structure. Work on the present bridge began in 1947, and was completed in 1948. The original truss spans were cut up and the new girder spans installed with minimal interruption to traffic.

Currently, the bridge consists of two 79-foot, three 69-foot and one 68-foot deck plate girder spans, set onto a combination of stone and concrete substructures. The superstructure follows a standard design, with heavy plate girders and an open deck. The substructures use a variety of designs. Piers #1, #3 and #5 were constructed in 1947, and use a unique column design, which is connected by a transverse arch at the top. Pier #2 was constructed in 1867 and pier #4 was constructed in 1890, and both were encased with concrete in 1903. Both piers consist of large rectangular shapes. The east abutment was constructed in 1900 and altered in 1903, and follows a standard elongated U-shape. The west abutment was constructed in 1890 and altered in 1903, and follows a standard design with sloped wing walls extending diagonally from the bridge. American Bridge Company fabricated the superstructure, and the spans were erected by employees of the IC. The original stone and concrete piers and abutments were constructed by unknown contractors, and local contractor W.D. Faus completed the concrete additions and encasements in 1903. It is unknown if piers #1, #3 and #5 were constructed by an unknown contractor or by railroad company forces. Deck plate girder spans were popular for railroad use, as they were durable and easy to construct. Since the 1948 reconstruction, the bridge has seen no significant alterations, and remains in regular use. Overall, the bridge appears to be in fair condition, with significant spalling throughout the substructure. The author has ranked the bridge as being locally significant, due to the common design and newer age.

Prior to the construction of this bridge, it is believed that a grade crossing existed at this location. Between late 1902 and 1904, the IC invested significant capital into the line through Webster City, significantly raising the tracks to eliminate a large sag through the town.

Citations

Build date and builder (superstructure)	American Bridge Company plaque
Builder (1903 substructure reconstruction)	Webster City Freeman; November 24, 1903
Railroad History Citation	ICC Valuation Information, Compiled by Richard S. Steele