All the substructures of this bridge indicate it was built in 1941. Historic aerial views confirm that the bridge here during the 1930s was a light weight through truss.
I inadvertently stumbled across a pony truss bridge, with the same railroad in Jones County (about half a state away). The pony truss there was abandoned in 1940, and has identical spans to this structure. These pony truss spans are each 6 panels, 113' long and were built by Lassig. These spans are identical in every way.
I suspect these trusses were relocated to this location in 1941, after abandonment. The Milwaukee Road was known for relocating truss spans, and reusing them at all costs.
Does anyone have any input on this? I strongly believe the spans at Jones County would have been relocated here in 1941.