From Michigan to Ontario, the International Bridge consists of a lift bridge for Locks 1 and 2, a dual-leaf Strauss Bascule for Locks 3 and 4, and a swing bridge over the Canadian lock.
Joe Granger posted 23 pictures of the Canadian side with the comment:
A few more high quality photos of some of the spans at the International Bridge between Sault Ste. Marie, Michigan and Sault Ste. Marie, Ontario. The swing span and trusses are from 1888, built jointly by the Soo Line, DSS&A and Canadian Pacific. The Bascule Bridge, the largest ever built, is from 1919, and the lift bridge was built in 1954 to replace another swing span. The red swing bridge is the last surviving emergency swing dam and still is swung twice a year. The bridge is now owned by CN. The bascule span is not opened anymore as the 3 and 4th lock are currently closed until a new lock is built.....whenever congress approves the funding. The project was approved decades ago, but they haven't released the funding.
Twice a day the bridges are closed for a trainIt appears the emergency swing dam swings a plate out over the canal and then the plate is turned from a horizontal to a vertical position to plug the canal.
More postings by Joe: an Oopsie Doodles with the lift span, after an accident with the bascule bridge, one leaf of the bascule being raised., all three movable spans, a video of the lift closing for a train then going back up for a boat, includes some detailed shots of the swing bridges gearing and lock pin, and a set that includes some downstream views of the dam,
Update: Joe Granger posted 6 closeups of the two US RR bridges with the comment: "Some photos of the 1945 Art Deco-ish machinery house and the worlds largest draw bridge (1913) at Sault Ste. Marie"
Canal Dimensions has details concerning the five locks.