- 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
06/26/21
This standard bridge crosses over Iowa Highway 146 north of Grinnell.
Featuring concrete substructures and a single through girder span, the bridge was built in 1915.
Overall, the bridge remains in good condition.
The author has ranked this bridge as being locally significant, due to the common design.
The photo above is an overview. The bridge can be accessed from the road below.