Click the photo to view the full-size version
| Name | BNSF Sevenmile Creek Bridge Chicago, Burlington and Quincy Railroad Bridge #372.35 |
| Built By | Chicago, Burlington & Quincy Railroad |
| Currently Owned By | BNSF Railway |
| Superstructure Contractor | American Bridge Company of New York (Lassig Plant) (Spans #2-#6) Unknown (Span #1) Unknown (Spans #7, #8 and #9) |
| Substructure Contractor | Unknown |
| Length | 374 Feet Total, 75 Foot Largest Span |
| Width | 2 Tracks |
| Height Above Ground | 50 Feet (Estimated) |
| Superstructure Design | Deck Plate Girder and Steel Stringer |
| Substructure Design | Concrete, Steel Tower and Steel Pile |
| Date Built | 1901, West End Reconstructed c. 1960 Using Spans Fabricated c. 1910 |
| Original Location | Unknown (Span #7) Unknown (Span #8) |
| Traffic Count | 25 Trains/Day (Estimated) |
| Current Status | In Use |
| Chicago, Burlington & Quincy Railroad Bridge Number | 372.35 |
| BNSF Railway Bridge Number | 372.35 |
| Significance | Moderate Significance |
| Documentation Date | 11/12/2016 |
In May 1854, the Burlington and Missouri River Railroad (B&MR) began constructing a new mainline across southern Iowa, with the goal of connecting the Mississippi River at Burlington, Iowa to the Missouri River near Omaha, Nebraska. In 1857, the first 34 miles between Burlington and the Skunk River near Rome, Iowa were completed. In 1859, an additional 41 miles between the Skunk River and Ottumwa, Iowa were completed. The railroad ceased progress during the Civil War, and eventually continued west in 1866. That year, an additional 24 miles were completed between Ottumwa and Albia, Iowa. Work continued in 1867, when an additional 46 miles were completed to Woodburn, Iowa. Between 1867 and 1868, the Chicago, Burlington & Quincy Railroad (CB&Q) constructed a bridge across the Mississippi River to connect this line to their lines in Chicago. In 1868, an additional 34 miles opened west to Afton, Iowa; followed by an additional 59 miles west to Red Oak, Iowa in 1869 and an additional 32 miles to the Pacific Junction, Iowa in 1870. In 1872, the B&MR was leased by the CB&Q; and was fully absorbed by the company in 1875. In the 1870s, the line would be extended into Nebraska, and in 1880, a bridge was constructed across the Missouri River at Plattsmouth.
This line formed a critical backbone for the CB&Q, connecting Chicago to territories west of the Missouri River. By the late 1870s, the need for a second track on this route had become apparent. A second track was constructed between Chillicothe, Iowa and Albia in 1879, including a new alignment around the south side of Albia. In 1880, a second track was constructed between Burlington and West Burlington, Iowa; as well as between Albia and Russell, Iowa. In 1885, a second track was constructed between Russell and Chariton, Iowa; followed by between Ottumwa and Chillicothe the following year. A large segment of second track opened between West Burlington and Mt. Pleasant, Iowa in 1889. By the turn of the 20th Century, several sections of this line required extensive upgrades in addition to a second track. In 1900, a second track was completed from Mt. Pleasant to Ottumwa and from Chariton to Creston, Iowa. A new alignment was constructed between Fairfield, Iowa and Batavia, Iowa; and between Agency, Iowa and Ottumwa in 1900. In 1901, the line was double tracked between Chariton and Creston. The 1901 work involved constructing a second single track alignment between Indianola Junction and Lucas, Iowa; between Woodburn and Osceola, Iowa and between Murray, Iowa and Creston. Between 1902 and 1905, the Creston to Pacific Junction segment was double tracked. In 1904, a realignment between Nodaway, Iowa and Emerson, Iowa opened to traffic; followed by a large realignment between Malvern, Iowa and Pacific Junction in 1905.
Throughout the 20th Century, this line remained critical to the CB&Q. The CB&Q invested significant capital into maintaining this line, replacing bridges, revising grades and changing the alignment in spots. One of the most prominent changes came in 1949, when the westbound track near Frederic, Iowa was straightened, to eliminate a segment of curvy original mainline. In 1970, CB&Q merged with Northern Pacific Railway and Great Northern Railway to form Burlington Northern Railroad (BN). Several segments of this line were single tracked in the mid to late 20th Century. In 1996, BN merged with Atchison, Topeka & Santa Fe Railway to form BNSF Railway, the current owner of this line. Today, this line remains a critical piece of railroad infrastructure. BNSF currently operates a portion of the Ottumwa Subdivision between Burlington and Creston; and a portion of the Creston Subdivision between Creston and Pacific Junction.
Located along Kansas Street west of Murray, this large deck plate girder viaduct carries a former Chicago, Burlington & Quincy Railroad mainline over Sevenmile Creek. Originally, the CB&Q ran on a different alignment, turning southwest from Murray and crossing Sevenmile Creek approximately 3,000 feet south of the present structure. Between 1900 and 1901, the CB&Q constructed a new alignment and double tracked the line between Murray and Creston. As part of the project, a new double track bridge was constructed on a more northerly alignment. As part of the project, a new double track viaduct was constructed across Sevenmile Creek. This viaduct initially consisted of seven deck plate girder spans with a timber pile trestle approach at either end. As the approach embankments settled, the bridge was rebuilt in 1913 with new concrete piers and abutments at either end, and the timber pile trestle spans were filled. Further alterations were made in approximately 1950, when the west end was rebuilt with a 32-foot deck plate girder span and a secondhand 32-foot steel stringer span, set onto timber pile substructures. The most recent alteration to the bridge came in approximately 1970, when the west end was further rebuilt by shortening the western 75-foot span and installing an additional secondhand 32-foot deck plate girder span, giving the bridge its present configuration.
Currently, the bridge consists of one 40-foot deck plate girder span (span #1), a 75-foot, a 30-foot, a 49-foot, a 30-foot and a 56-foot deck plate girder spans (spans #2-#6), two 32-foot deck plate girder spans (spans #7 and #8) and a 30-foot steel stringer span (span #9). The bridge is supported by concrete abutments, a concrete pier (pier #1), two steel towers and two steel pile piers (piers #4 and #5). The main portion of the bridge follows a standard design, with two heavy plate girders for the main spans and two lighter plate girders for the tower spans. The ends of the 75-foot spans are tapered, giving the spans a "fish-belly" appearance. As part of the c. 1970 reconstruction, the western 19 feet of span #6, including the original tapered end, were removed. The approach spans (spans #1, #7 and #8) also use a standard design, with shallow girders covered by an open deck (span #1) and a ballast deck (spans #7 and #8). The west span (span #9) uses a standard mid-20th Century design, with shallow beams and a ballast deck. The piers consist of a rectangular concrete structure (pier #1) and steel piles capped with concrete (piers #4 and #5). The towers are constructed using heavily constructed V-laced beams and a transverse plate girder at the top, and are supported by square pedestals. These pedestals appear to have been reinforced with concrete reinforcements. The east abutment uses a standard U-shaped design, while the west abutment uses a more modern design.
American Bridge Company fabricated spans #2 through #6 at their Lassig Plant in Chicago, while the east span (span #1) was fabricated by an unknown firm with a square plaque. Spans #7 and #8 were fabricated by unknown contractor(s) in approximately 1910 for use at an unknown location, while span #9 was also fabricated by an unknown contractor. It is unclear if the substructures were constructed by railroad company forces or by an unknown contractor. It is known that other projects along this line used company forces to construct concrete bridges, and it is likely that the c. 1970 substructures were also constructed by company forces. Railroads often reused steel and iron spans, as it provided a cost effective way to upgrade bridges without requiring significant amounts of new material. Deck girder viaducts were popular for tall and long bridges, as the design provided the most economical solution. Deck plate girder spans were also popular for railroad use, as they were durable and easy to construct. Since the c. 1970 alterations, the bridge has seen no significant changes, and remains in use as part of a heavily used BNSF Railway mainline. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked this bridge as being locally significant, due to the common design. A number of similar viaducts were constructed along the CB&Q in Iowa.
Citations
| Build date and builder (spans #2 through #6 superstructure) | American Bridge Company plaque |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |