Patented in 1844 by Thomas and Caleb Pratt, the Pratt truss began as a wood bridge design but shifted to wrought iron and then steel as those materials became more available, allowing heavier loads with less frequent repair. Because it was economical to fabricate, simple to assemble, built from standard-sized components, and adaptable to wider spans by joining trusses together, it became the most common bridge type used in the late 1800s and early 1900s. The Illinois Central Railroad bridge across the Little Sioux River was constructed in 1887 by Union Bridge Company, and for nearly 90 years it carried trains, with several crossing each day around 1900. As train traffic declined in the 1950s, the tracks were removed in 1979, the east metal span was demolished in the 1990s, and in 2006 the bridge was rehabilitated, preserving the original west steel span and stone piers, replacing deteriorated wooden trestle approaches with steel piling bents, and providing a river crossing for the trail connection to Little Sioux Park. As a vanishing type of structure, it reflects the importance of railroads to Iowa's development and stands as an example of late 1800s bridge design.