First Coast Railroad

Amelia River Swing Bridge (Nassau County, Florida)
Built 1920 by the Virginia Bridge & Iron Co.
Polygonal Warren through truss bridge over Amelia River on First Coast Railroad (formerly Seaboard Air Line Railway)
Open to traffic

Seaboard Air Line Railway St. Mary's River Bridge (Nassau County, Florida)
Built 1926 by the Mt. Vernon Bridge Co. for the Seaboard Air Line Railway
Deck plate girder bridge over St. Mary's River on First Coast Railroad
Open to traffic