CPKC Walnut Creek Bridge (Rathbun, East)

Located near County Road J29, this through plate girder bridge is the eastern crossing of Walnut Creek along the former Chicago, Milwaukee, St. Paul & Pacific Railroad (Milwaukee Road) mainline in Rathbun. The first bridge at this location was likely a timber truss bridge, constructed when the line was first built. In the mid-1890s, the Milwaukee Road made significant improvements to this line, replacing the first generation of bridges with new steel structures. In 1895, the original bridge was replaced with a 75-foot through plate girder span, fabricated by the Lassig Bridge & Iron Works of Chicago, Illinois. In 1903, two deck plate girder spans set onto concrete substructures were added at the west end to replace a timber pile trestle approach. As trains became heavier in the 20th Century, the Milwaukee Road undertook another improvement project along this line through the 1930s, replacing many of the 1890s bridges with heavier structures of a similar design. In 1939, a new through plate girder span was installed on a new concrete abutment, giving the bridge its present configuration. It is likely that the 1895-era span was reused at another location, possibly on a branch line. Currently, the bridge consists of a 75-foot type "C4" through plate girder span, approached by two 45-foot standard deck plate girder spans on the west end. The entire bridge is set onto concrete substructures, which were constructed in 1903 and 1939.

The main span follows a standard design, with two heavy plate girders, square girder ends and a standard floor. Type "C4" girder spans were a standard Milwaukee Road design, and differed from type "C3" spans in the use of two heavier stringers instead of the four lighter stringers seen on "C3" spans. The approach spans also follow a standard design, with two heavy plate girders per span and an open deck. The west abutment follows a standard Milwaukee Road design, with sloped wing walls, while the east abutment appears to be more modern and use smaller wing walls. The piers both consist of large rectangular structures. Bethlehem Steel Company fabricated the main span, while an unknown contractor fabricated the approach spans. It is believed the west abutment and piers were constructed by railroad company forces, while it unclear if the east abutment was constructed by railroad company forces or by an unknown contractor. Girder spans were popular for railroad use, as they were durable and easy to construct. During the early 20th Century, the Milwaukee Road used company labor almost exclusively to construct concrete bridges and culverts, as the company found this arrangement to be more cost effective than constructing masonry by contract. Since the 1939 reconstruction, the bridge has seen no significant alterations, and remains in regular use. Overall, the bridge appears to be in fair condition, with some spalling noted to the east pier. It appears that the west pier may have been encased in concrete at some point. The author has ranked this bridge as being locally significant, due to the common design.