Oskaloosa Rail Bridge

• 1867: 16 miles completed from Ackley to Eldora, Iowa by the Eldora Railroad and Coal Company
• 1868: 27 miles completed from Eldora to Marshalltown, Iowa by the Iowa River Railway
• 1868: Eldora Railroad and Coal Company sold to the Iowa River Railway
• 1869: Iowa River Railway sold to the Central Railroad Company of Iowa
• 1871: 65 miles completed from Northwood to Ackley, Iowa by the Central Railroad Company of Iowa
• 1871: 81 miles completed from Marshalltown to Albia, Iowa by the Central Railroad Company of Iowa
• 1878: Central Railroad Company of Iowa sold to Central Iowa Railway
• 1882: 98 miles completed from Oskaloosa to the Mississippi River across from Keithsburg, Illinois by the Chicago, Burlington & Pacific Railroad
• 1882: CB&P sold to the Central Iowa Railway
• 1883: 83 miles completed from Keithsburg to Peoria, Illinois by the Central Iowa Railway Company
• 1886: Mississippi River Bridge completed at Keithsburg by the Keithsburg Bridge Company
• 1889: Central Iowa Railway sold to the Iowa Central Railway
• 1895: Minneapolis & St. Louis Railway reorganizes as the Minneapolis & St. Louis Railroad
• 1901: Iowa Central Railway controlled by the Minneapolis & St. Louis Railroad
• 1901: Keithsburg Bridge Company sold to the Iowa Central Railway
• 1912: Iowa Central Railway sold to the Minneapolis & St. Louis Railroad
• Ca. 1920: Minneapolis & St. Louis Railroad reorganizes as the Minneapolis & St. Louis Railway
• 1960: Minneapolis & St. Louis purchased by the Chicago & North Western Railway
• 1962: Beacon, Iowa to Eddyville, Iowa segment abandoned, operations begin over parallel Rock Island tracks
• 1971: Oskaloosa, Iowa to Keithsburg, Illinois segment abandoned
• 1976: Keithsburg, Illinois to Middle Grove, Illinois segment abandoned
• 1988: Hampton, Iowa to Ackley, Iowa segment abandoned
• 1990: Rockwell, Iowa to Sheffield, Iowa segment abandoned
• 1995: C&NW purchased by Union Pacific Railroad
• 2001: Eddyville, Iowa to Albia, Iowa segment abandoned
• 2001: Sheffield, Iowa to Hampton, Iowa segment abandoned
• 2006: Ackley, Iowa to Marshalltown, Iowa segment sold to the Iowa River Railroad
• 2008: Middle Grove, Illinois to Peoria, Illinois segment abandoned
• 2011: Steamboat Rock, Iowa to Marshalltown, Iowa abandoned and purchased by Marshall and Hardin Counties
• 1995-Present: Union Pacific operates the Oskaloosa Subdivision between Marshalltown and Eddyville
• 2006-Present: Iowa River Railroad operates between Ackley and Steamboat Rock
• 2011-Present: Iowa River Rail Trail being developed between Steamboat Rock and Marshalltown

Located just north of Oskaloosa, this unique deck truss bridge crosses the South Skunk River.
Built in 1901 to replace a previous, lighter bridge; this bridge a single unique deck truss span. Like many truss bridges along this route, this structure contains a unique design, which is considered to be a Schaub Variant truss.
The main truss has 6 panels with riveted connections. The bridge also features unique subpanels in four panels. The substructures of the bridge are made of concrete, and the approaches built of trestle approach. This railroad is the only route that had trusses of this design, making it a relatively unique design. However, this is the only bridge known to utilize the design on a deck truss.

Diagram of this style bridge

The Schaub variant truss is a take on the traditional Warren design, developed by Julius Schaub in 1901. While the original design featured a combination of pin and riveted connections, this bridge utilizes purely riveted connections.
The Schaub design offered a savings of material and a reduction of traditional stresses in truss members. Schaub considered it to be an ideal link between long pin connected spans and short riveted spans.
Overall, the bridge appears to be in fair to good condition, with little serious deterioration.

The author has ranked this bridge as being regionally significant, due to the unique truss design and large size.
The photo above is an overview.