Just east of Freeburg, MO. Built in 1902 and stretches a whopping 1,776 feet. Planned to be a future section of the Rock Island Trail, which would be pretty cool.
"The Chicago Rock Island & Pacific Railroad completed construction on this massive bridge in 1903. Officially the largest railroad bridge in the state of Missouri, it exceeds 1800 feet in length and sails 110 feet above the Gasconade River and valley. Rail traffic was heaviest during World War II, when an armed guard kept watch from a small shack at the bridge's western end. After this period, the frequency of trains slowly diminished until the railroad's poor financial state caused the end of regular service in August of 1979. The final train is said to have crossed in December of that year. The bridge's official number was 1146." Source: bridgehunter.com/mo/osage/gascondy/
Song called "The Impossible" by Tony Anderson.