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| Name | CN East Boyer River Bridge Illinois Central Railroad Bridge #WA449.1 |
| Built By | Illinois Central Railroad |
| Currently Owned By | Canadian National Railway |
| Superstructure Contractor | American Bridge Company of New York |
| Length | 187 Feet Total, 79 Foot Main Span |
| Width | 1 Track |
| Height Above Ground | 20 Feet (Estimated) |
| Superstructure Design | Through Plate Girder and Steel Stringer |
| Substructure Design | Steel Pile |
| Date Built | 1966 |
| Traffic Count | 2 Trains/Day (Estimated) |
| Current Status | In Use |
| Illinois Central Railroad Bridge Number | WA449.1 |
| Canadian National Railway Bridge Number | 449.1 |
| Significance | Minimal Significance |
| Documentation Date | 12/30/2018 |
Between 1857 and 1870, the Dubuque and Sioux City Railroad (D&SC) had acquired and constructed a mainline across central Iowa, extending from the Mississippi River at Dubuque, Iowa to the Missouri River at Sioux City, Iowa. The D&SC had operated under lease from the Illinois Central Railroad (IC) since 1867, and connected to the IC system by using a bridge across the Mississippi River at Dubuque. This line provided several opportunities for the construction of branch lines. By the late 19th Century, the IC desired to enter the Council Bluffs, Iowa/Omaha, Nebraska markets. In 1890, the Omaha Bridge & Terminal Railway (OB&T) began construction on a line extending between Council Bluffs, Iowa and Omaha, Nebraska. A new bridge was constructed across the Missouri River between 1893 and 1894, with the goal of breaking the Union Pacific Railroad (UP) monopoly of traffic crossing the Missouri River at Omaha. Between September 1898 and January 1900, the Fort Dodge and Omaha Railroad (FD&O) constructed a 131-mile railroad line, extending from the existing D&SC mainline at Tara, Iowa to Council Bluffs, Iowa. The FD&O and OB&T were both leased by the D&SC/IC in 1899.
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 secondary mainline for the company, connecting Chicago to the Missouri River at Omaha. 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 bridge across the Missouri River was placed out of service in approximately 1980, although the tracks remain today. 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 Omaha Subdivision between Tara and Council Bluffs.
Located in Denison, this through plate girder bridge carries a former Illinois Central Railroad mainline over the East Boyer River. Since the railroads first arrived in the area, the Boyer River had been troublesome, often flooding, washing out tracks and requiring larger bridges to be constructed. The first bridge at this location consisted of a 75-foot and two 30-foot through plate girder spans, set onto concrete substructures. This bridge was built in 1899, using spans fabricated by American Bridge Works. In 1966, the river channel was improved, and a new bridge constructed. The old bridge was completely removed, and it is likely that the previous spans were reused elsewhere, possibly along this line. Currently, the bridge consists of a 79-foot through plate girder span, flanked by a 48-foot steel stringer span on either end. In addition, a 12-foot steel stringer span approaches the south end and the bridge is set onto steel pile substructures. The superstructure follows a standard design for the mid to late 20th Century, with welded joints, heavy plate girders and an open floor. The one exception is the 12-foot span, which has more rivets and appears more similar to a 1930s or 1940s design. It is unclear if the 12-foot span was reused from another location, or is original to this location. The substructures use a standard modern design, with steel H-piles and concrete caps. American Bridge Company fabricated the superstructure, while it is believed the substructures were constructed by railroad company forces. Through plate girder spans were popular for railroad use, as they were durable and easy to construct. Since the initial construction, the bridge has seen no significant alterations, and remains in regular use. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked the bridge as being minimally significant, due to the common design and newe age.
Citations
| Build date and builder (superstructure) | American Bridge Company plaque |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |