BNSF Rock River Bridge (Oregon)

Oregon, Ogle County, Illinois

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Name	BNSF Rock River Bridge (Oregon) Chicago, Burlington and Quincy Railroad Bridge #98.18
Built By	Chicago, Burlington & Quincy Railroad
Currently Owned By	BNSF Railway
Superstructure Contractor	McClintic-Marshall Construction Company of Pittsburgh, Pennsylvania (Trusses) American Bridge Company of New York (Deck Girders)
Length	532 Feet Total, 132 Foot Main Spans
Width	1 Track
Height Above Ground	20 Feet (Estimated)
Superstructure Design	Pratt Through Truss and Deck Plate Girder
Substructure Design	Stone Masonry and Concrete
Date Built	1904
Traffic Count	20 Trains/Day (Estimated)
Current Status	In Use
Chicago, Burlington & Quincy Railroad Bridge Number	98.18
BNSF Railway Bridge Number	98.18
Significance	Moderate Significance
Documentation Date	3/27/2015; 3/19/2023

In 1868, the Ogle and Carroll County Railroad (O&CC) began construction on 16 miles of new railroad, extending from Rochelle to Oregon, Illinois. In early 1869, the Chicago and Iowa Railroad Company (C&I) began construction on a 45-mile section of new railroad to connect Aurora, Illinois with the line at Rochelle. The O&CC merged into the C&I in 1871. The Aurora to Rochelle segment would be completed in 1871, and the portion to Oregon completed in 1873. At Aurora, the railroad connected to the Chicago, Burlington & Quincy Railroad mainline. The CB&Q had begun to construct and acquire a large network of railroads through the Midwest. Because the CB&Q was affiliated with the railroads owned by James J. Hill in Minnesota, a connection between the two systems was desired. Between 1883 and 1886, the Chicago, Burlington & Northern Railroad (CB&N) constructed 330 miles of new railroad, extending from Oregon, Illinois to Savanna, Illinois; then north along the Mississippi River through La Crosse, Wisconsin; to St. Paul, Minnesota. The CB&N and C&I would both be sold to the CB&Q in 1899. By the early 20th Century, traffic had significantly increased on the northern portion of the line. Double tracking projects were begun in 1910, with the entirety of the Savanna to La Crosse line double tracked by 1916. North of La Crosse, short sections were double tracked in the 1910s, but the majority was constructed between 1927 and 1929. This route served as a principal mainline for the CB&Q, providing a connection to the transcontinental lines of the Northern Pacific Railway and Great Northern Railway. In 1970, the CB&Q was merged with the Northern Pacific Railway and the Great Northern Railway to form Burlington Northern Railroad (BN). In 1996, BN merged with Atchison, Topeka & Santa Fe Railway to form BNSF Railway. BNSF currently operates the Aurora Subdivision between Aurora and La Crosse, and the St. Croix Subdivision between La Crosse and St. Paul. The line continues to serve as a critical mainline for BNSF, and makes up a portion of the northern BNSF transcontinental route.

Located in Oregon, this through truss bridge carries the BNSF Railway across the west channel of the Rock River. The first bridge here likely utilized a wooden or light iron truss. In 1892, the bridge would be reconstructed with a new steel through truss bridge, set onto stone substructures. This bridge consisted of four 132-foot, 6-panel, pin-connected Pratt through truss spans, which utilized a lightweight design standard for CB&Q bridges of the era. By 1904, this bridge had become too light for traffic, and a new bridge would be constructed. It is likely that the four spans of the old bridge were reused on a branch line or an overpass. Currently, the bridge consists of two 132-foot, 6-panel, pin-connected Pratt through truss spans, approached by two 67-foot deck plate girder spans on either end. The bridge uses stone abutments and piers from the previous bridge, and new concrete piers were added in 1904. McClintic-Marshall Construction Company fabricated the truss spans, while American Bridge Company fabricated the approach spans. The trusses utilize a design standard to the CB&Q during the late 1900s and early 1910s, using a combination of pinned and riveted connections, heavy members and the standard CB&Q portal. This particular portal bracing design utilizes a shallow lattice design, with angular heel bracing. As this portal design was a CB&Q standard, it was used on truss bridges from the 1890s until the 1930s. The Pratt through truss design was the most common railroad truss bridge design in the late 19th Century, before it was superseded by riveted Warren designs in the early 20th Century. The CB&Q continued to use pin connected trusses until approximately 1905, when the railroad switched to using riveted designs. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked this bridge as being moderately significant, due to the truss design.

Citations

Builder and build date	CB&Q - Allen Moore collection - BRHS Archives
Railroad History Citation	ICC Valuation Information, Compiled by Richard S. Steele