The Sault Ste. Marie Railroad Bridge was originally built in 1887 to facilitate rail traffic crossing St. Marys River and the international border between Sault Ste. Marie, Michigan and Sault Ste. Marie, Ontario. It runs parallel to the Sault Ste. Marie International Bridge.
The bridge carries the CN Manistique Subdivision over the St. Mary's River, which includes the Soo Locks Canals in Michigan, the St. Mary's Falls in Michigan & Ontario, the Sault Ste. Marie Canal in Ontario, and finally the remainder of the river in Ontario.
It consists, from south to north, of a small plate girder bridge overpass spanning West Pier Drive, a lift bridge, a bascule bridge, a nine-span thru-truss bridge, a swing bridge, and finally another plate girder bridge. The earliest part of the bridge where the thru-truss spans, which were completed in 1887. As the Soo Locks were enlarged for larger ships, some of the thru-truss spans were removed and replaced by lift, bascular and swing bridges.