IAIS Bulger Creek Bridge (Middle)


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Name IAIS Bulger Creek Bridge (Middle)
Chicago, Rock Island & Pacific Railroad Bridge #3805
Built By Chicago, Rock Island & Pacific Railway
Currently Owned By Iowa Interstate Railroad
Superstructure Contractor Unknown
Substructure Contractor Unknown
Length 108 Feet Total
Width 1 Track
Height Above Ground 10 Feet (Estimated)
Superstructure Design Warren Through Truss
Substructure Design Concrete
Date Built 1905
Traffic Count 3 Trains/Day (Estimated)
Current Status In Use
Chicago, Rock Island & Pacific Railroad Bridge Number 3805
Iowa Interstate Railroad Bridge Number 380.50
Significance Moderate Significance
Documentation Date 7/21/2012; 6/30/2013; 11/5/2017

In 1869, the Chicago, Rock Island & Pacific Railroad (Rock Island) constructed 142 miles of new railroad, extending from the end of the existing mainline at Des Moines, Iowa to Council Bluffs, Iowa.  Originally, the line went west to Atlantic, Iowa; before turning northwest and going through Avoca, Iowa and Shelby, Iowa.  At Shelby, the line would turn back southwest, and run through Neola, Iowa and Underwood, Iowa before arriving in Council Bluffs.  In 1880, the Rock Island was reorganized as the Chicago, Rock Island & Pacific Railway.  The Rock Island constructed and acquired a large network of railroads during the late 19th Century, covering much of the central United States.  This line became part of the principal mainline of the Rock Island, and allowed for further development of branch lines throughout central Iowa and eventual expansion west of the Missouri River.  In the late 19th Century, several improvements were made to the line, including revising grades, curves and replacing wooden bridges with stone and iron structures. 

The Rock Island struggled financially throughout much of its history, experiencing repeated bankruptcies and chronic instability.  After World War II, the Rock Island struggled to survive, proposing mergers and deferring maintenance on their routes. The railroad reorganized as the Chicago, Rock Island & Pacific Railroad in 1948. During the early 1950s, the Rock Island undertook a series of improvements in Western Iowa to eliminate harsh grades and shorten the line.  Between 1952 and 1953, the Rock Island constructed the Atlantic Cutoff, which included constructing 34 miles of new railroad between Atlantic and McClelland, Iowa.  West of McClelland, the Rock Island used the Chicago Great Western Railway (CGW) tracks to reach Council Bluffs. The new route saved 10 miles, and much of the old route was abandoned in 1953.  A short segment was retained between Walnut, Iowa and Shelby, which was abandoned in 1966.  An additional revision was made near Adair in 1954, which involved straightening the route.  By the mid-1970s, the railroad was in serious decline.  The railroad secured loans to eliminate slow orders, acquired new equipment, and attempted to restore profitability.  Several sections of this line had fallen into serious disrepair, hampering the Rock Islands ability to maintain efficient operations.  In 1978, the railroad came close to profit, but creditors were lobbying for a complete shutdown of the Rock Island.  During the fall of 1979, a strike crippled the railroad, and by January of 1980, the entire system was ordered to be shut down and liquidated.  Many of the lines and equipment were scrapped.  Profitable sections of railroad were prepared for sale.  

In November 1981, the Iowa Railroad Company (IARR) began operations over the former Rock Island mainline in western Iowa.  In June 1982, the IARR entered into a two-year lease for the entire Rock Island mainline between Bureau, Illinois and Council Bluffs.  In 1983, concerns had grown over the ability of the IARR to provide reliable service to shippers along the line, and several industries came together to form Heartland Rail Corporation, which purchased the line between Bureau and Council Bluffs from the Rock Island trustees.  Iowa Interstate Railroad (IAIS) was chosen to operate the line, and began operations in late 1984.  After years of thin profit margins, IAIS began making significant financial strides in the 1990s and early 2000s, eventually becoming a major railroad in central Iowa.  Increased profit margins and large grants meant IAIS could rebuild deteriorated track, improve bridges and expand operations.  Today, IAIS continues to operate the Council Bluffs Subdivision between Des Moines and Council Bluffs.  Except for a short portion near Shelby, the entirety of the original mainline between Atlantic and Council Bluffs remains abandoned.


Located south of De Soto, this through truss bridge is the middle of three bridges carrying a former Chicago, Rock Island & Pacific Railroad (Rock Island) mainline over Bulger Creek. The first bridge at this location was likely a timber pile trestle, constructed when the line was first built. It is unclear if the original timber bridge was replaced by an iron or steel structure in the 19th Century. During the early years of the 20th Century, the Rock Island invested significant capital into this line, replacing timber bridges with steel and concrete structures. In 1905, the present steel truss bridge was constructed. Currently, the bridge consists of a 108-foot, 6-panel, riveted Warren through truss span, set onto concrete abutments. An unknown contractor fabricated the truss span, while it is believed that the abutments were constructed by railroad company forces. It is possible that American Bridge Company fabricated the span, although there are no plaques to indicate this. Most bridges constructed by the Rock Island during this era were fabricated by this builder. It is unclear if any repairs have been made to the superstructure since it was first constructed.

The truss span follows a standard Rock Island design that was used in the early 20th Century, with heavy members, riveted connections and a traditionally composed floor. Both the top chord and endposts consist of heavily constructed members, built of two U-shaped channels connected by solid plates on the top/exterior and V-lacing on the bottom/interior. The bottom chord is constructed of a solid beam. The vertical members are also constructed of solid beams, while the diagonal members are composed of built-up beams which use V-lacing on both sides. The floor system is composed of heavy plate girder floorbeams placed at the panel points and two heavy plate girder stringers. The portal bracing uses a standard Rock Island design, consisting of a lattice design with four "X"s. At the corners, a triangular heel bracing with a rounded edge connects the bottom of the portal bracing to the endposts. The sway bracing uses a similar design to the portal bracing, with 4 "X"s and plates at the connections. The upper lateral bracing is composed of light V-laced beams, while the lower lateral bracing is constructed of L-shaped bars. The abutments use a standard U-shaped design, and have been repaired with additional concrete.

Warren trusses became popular in the early 20th Century as an alternative to pin-connected Pratt truss spans. Throughout the late 19th Century, the Rock Island primarily preferred using lattice trusses for through truss spans. However, once heavier riveted Warren trusses were introduced around 1900, the Rock Island quickly switched to using this design as the preferred truss bridge configuration. Dozens of similar spans were constructed by the Rock Island between 1900 and 1920. Riveted Warren trusses were economical and simple, while also being far stronger than pin-connected Pratt spans constructed in the 19th Century. Since the initial construction, the bridge has seen only minor alterations, including the encasement of the abutments in a concrete facing. Today, the bridge continues to carry railroad traffic. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. This bridge is likely to be replaced in the coming years, as Iowa Interstate Railroad is seeking to replace all truss bridges on their mainline. The author has ranked this bridge as being moderately significant, due to the truss design.


Citations

Build date Chicago, Rock Island & Pacific Railway Valuation Engineering Field Notes at the National Archives
Railroad History Citation ICC Valuation Information, Compiled by Richard S. Steele

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