L&N Railroad Bridge. The railroad bridge over the Green River stands a quarter mile to the southwest. Constructed 1857-59 by engineer Albert Fink, the bridge was at the time the largest iron bridge in the United States, with a total length of 1,800 ft. Stonemasons John W. Key & sons built the piers from local limestone. (Reverse) The L&N railroad bridge became vital in the Civil War. Two battles were fought here for control of this major link. Confederate General Simon B. Buckner ordered Key to destroy two spans to prevent Union use. Bridge repaired by Union and later reengineered.