- 1857: 44 miles completed from Clinton to Wheatland, Iowa by the Chicago, Iowa and Nebraska Railroad
- 1858: 20 miles completed from Wheatland to Lisbon, Iowa by the Chicago, Iowa and Nebraska Railroad
- 1859: 17 miles completed from Lisbon to Cedar Rapids, Iowa by the Chicago, Iowa and Nebraska Railroad
- 1861: 41 miles completed from Cedar Rapids to Belle Plaine, Iowa by the Cedar Rapids and Missouri River Railroad
- 1861: 41 miles completed from Cedar Rapids to Chelsea, Iowa by the Cedar Rapids and Missouri River Railroad
- 1862: 29 miles completed from Chelsea to Marshalltown, Iowa by the Cedar Rapids and Missouri River Railroad
- 1864: 29 miles completed from Marshalltown to Nevada, Iowa by the Cedar Rapids and Missouri River Railroad
- 1865: 29 miles completed from Nevada to Boone, Iowa by the Cedar Rapids and Missouri River Railroad
- 1867: 150 miles completed from Boone to Council Bluffs, Iowa by the Cedar Rapids and Missouri River Railroad
- 1867: 6 miles completed from Missouri Valley to California Junction, Iowa by the Cedar Rapids and Missouri River Railroad
- 1884: CI&N and CR&MR officially acquired by Chicago & North Western Railway
- 1887: 6 miles completed from Beverly to Otis, Iowa bypassing Cedar Rapids by the Linn County Railway
- 1887: Linn County Railway acquired by Chicago & North Western Railway
- 1891-98: Second track constructed between Clinton and Cedar River
- 1898-1900: Second track constructed between Cedar River and Mashalltown
- 1898-1901: New alignment completed between Boone and Ogden, Iowa; including the Des Moines River Bridge
- 1900-02: Second track constructed between Marshalltown and Council Bluffs
- 1933: Old route via Moingona between Boone and Ogden abandoned
- 1995: Chicago & North Western purchased by Union Pacific Railroad
- 1995-Present: Union Pacific operates the Clinton Subdivision between Clinton and Boone
- 1995-Present: Union Pacific operates the Boone Subdivision between Boone and Missouri Valley
- 1995-Present: Union Pacific operates the Omaha Subdivision between Missouri Valley and Council Bluffs
01/14/22
The most unique railroad bridge in Ames is this structure, which carries the Union Pacific mainline across the South Skunk River.
The bridge was originally built in 1900 as a replacement for a single track bridge. It is likely that the girders were fabricated in approximately 1898. Two spans were replaced in 1949 with a larger span, possibly due to scouring of the center pier or the need for channel improvements.
In response, American Bridge Company was contracted to rebuild the structure. A large deck girder span was installed, along with I-Beams on either side. On the west end, a single deck girder remained of the original bridge.
The bridge currently sits on both concrete and stone substructures. The concrete substructures are of a design commonly seen on 50s bridges.
The author has ranked the bridge as being locally significant, due to the common design but unique history.
The photo above is an overview. The structure can be accessed from the pedestrian trail underneath.
| Upstream | Ellsworth Railroad Bridge |
| Downstream | UP S. Skunk River Bridge (Cambridge) |