- 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
Along the former Chicago & North Western mainlines, there are numerous road bridges utilizing former railroad bridge parts. This structure is no different.
Built sometime after 1918, the bridge has served traffic on Webster Street for quite some time. The bridge features a pretty basic double intersection Warren Pony Truss, which has been converted to road use. Unlike many of the similar trusses, this bridge has laced members.
From a basic inspection, one can assume that the bridge was extensively rebuilt for road use. Improvements likely included the removal of the original railroad deck and many structural steel components. Empty rivet holes and hacked off members can be seen.
One of these improvements was the construction of outriggers, to strengthen the deck. In addition, blocks with bolts through it, which can be described as tension blocks, hold the truss lines to a rebuilt floor. The floor is built out of metal floor beams and wooden stringers. None of this floor is original to the truss.
As for the original location and build date of the bridge, it is likely that the truss dates to the 1880s. However, the original location of the bridge has not yet been determined.
It is possible that it could have originally been located somewhere close by, such as a crossing of Linn Creek. However, other similar crossings have shown that the spans could have come from anywhere.
The bridge overall contains the truss, which features riveted connections. In addition, the bridge is approached by trestle spans and rests on wooden piers, which sit on concrete blocks.
The author has ranked the bridge as being moderately significant, due to the unique design and interesting history. The road has been closed for quite some time, since at least 2014, due to deterioration throughout the timber components of the bridge.
The photo above is an overview. The bridge can be accessed from the road which it carries.