The Aerial Lift Bridge
Near Duluth, Minnesota
Stand at the base of the Aerial Lift Bridge on a clear morning and watch it rise. The whole upper span, nearly four hundred feet of steel truss, weighing nine hundred tons, lifts straight up on its towers in under a minute to let an ore carrier through, then descends again with the same unhurried precision. People on the Canal Park boardwalk stop and stare every time, even those who have watched it a hundred times before.
The bridge's history is stranger than its present. When it was built in nineteen oh five, it was not a lift bridge at all. It was a transfer bridge, a gondola car hung from the upper truss that swung pedestrians and wagons across the Duluth Ship Canal between the mainland and Minnesota Point.
This was an unusual engineering solution to an unusual problem: the canal was narrow enough that a proper draw bridge would have blocked shipping traffic, but wide enough to make a simple footbridge impossible. The canal itself had a complicated origin. In eighteen seventy-one, Duluth businessmen dug it without federal permission, cutting a channel through the sandbar known as Minnesota Point to give their harbor direct access to Superior Bay.
Wisconsin interests worried about the harbor at Superior won an injunction against the project, but by then the canal was already open. But the ships were already using it, and what is done is done. The canal stayed.
For twenty-four years, passengers swung back and forth across the canal in the gondola car before engineers redesigned the structure in nineteen twenty-nine and converted it to a vertical lift bridge. The new mechanism was faster, stronger, and could accommodate ships with tall superstructures that the old gondola clearance would have snagged. It became one of the most photographed structures in Minnesota, the emblem of a harbor city that never lost its sense of the theatrical.
Today the bridge rises and descends dozens of times a day in shipping season. If you time your visit to Canal Park, you can watch the whole performance, the long horn blast from the approaching vessel, the span rising, the ship sliding through on its way to one of the largest inland ports in the world.
