The Milwaukee Road did a mass-abandonment in 1980, shedding off its entire Pacific Extension and also numerous lines in the Midwest. It was a desperate measure to shed off weaker lines and retreat to a financially solvent core system. Among the lines that were axed was the former E/W main across IA that went through Cedar Rapids. So the bridge was probably torn out within a short time following its 1980 abandonment date.
It was built in 1905 and widened in 1912-13. The first bridge (1881-1905) across Cedar River was about a mile further south and the right-of-way sloped down the east side of the river. The grade and the piers can still can be seen today.
Probably lost to the MILW needing money in its last days. Steel has scrap value.
Was this bridge lost to flooding in 1985, or lost to "progress?"
See the ruins before IA-100 is built over them