Built in 1903 by American Bridge Company to replace the Patterson Viaduct, the Baltimore & Ohio railroad bridge runs over Ilchester Road and Patapsco River into the Ilchester Railroad Tunnel. The bridge is comprised of two parts. The west side (crossing the road) is constructed using a riveted plate pony girder. The east side uses a Pratt through truss span to cross the Patapsco River. At the east end of the bridge, the rail line continues into a brick-faced arch railroad tunnel (Ilchester Railroad Tunnel). Initially carrying two rail tracks, the bridge’s total length is 266 feet. It was constructed from 604,228 pounds of structural steel. The bridge is still in use today (carrying a single track and renamed the Patapsco River Bridge), run by CSX Railroad.