Aerial Lift Bridge

The Aerial Lift Bridge in Duluth, Minnesota, is an engineering marvel and a historic landmark that has become an iconic symbol of the city. This extraordinary structure, which spans the Duluth Ship Canal, offers more than just a means of crossing; it provides a glimpse into the rich history and innovative spirit of Duluth. Whether you're a history buff, an engineering enthusiast, or simply a curious traveler, the Aerial Lift Bridge is a must-see attraction that promises to leave you in awe.

The Genesis of the Aerial Lift Bridge

The story of the Aerial Lift Bridge begins in the late 19th century when the need for a reliable crossing over the Duluth Ship Canal became evident. The canal, created in 1870-1871, cut through Minnesota Point, a sand spit that extended into Lake Superior. This new waterway allowed ships easier access to the port but also left the residents of Minnesota Point in need of a dependable way to traverse the canal. Various methods, including ferries and a swinging footbridge, were tried but proved inadequate, especially during the harsh winter months when ice impeded travel.

In 1892, a contest was held to find a more permanent solution. John Low Waddell's design for a high-rise vertical lift bridge won the competition, but the War Department's objections halted its construction. However, the idea of a transporter bridge persisted, and by 1905, the Aerial Bridge, designed by city engineer Thomas McGilvray, was completed. This innovative structure featured a gondola that could ferry people, wagons, streetcars, and automobiles across the canal in about one minute.

Transformation into a Vertical-Lift Bridge

As Duluth grew and the demand for vehicular traffic increased, the Aerial Bridge's capacity was soon outstripped. A more efficient design was needed, leading to the bridge's transformation into a vertical-lift bridge in 1929-1930. The redesign, attributed to C.A.P. Turner, was a descendant of Waddell's original concept. The new structure incorporated a lifting platform that could be raised to a height of 135 feet, allowing tall ships to pass beneath with ease. The transformation was a significant engineering feat, involving the modification of support columns and the addition of counterweights to balance the lifting span.

The newly converted Aerial Lift Bridge first lifted for a vessel on March 29, 1930, and has been in continuous operation since. Today, it raises about 5,000 times per year, accommodating the bustling maritime traffic that passes through the Duluth Ship Canal.

A Living Landmark

The Aerial Lift Bridge is not just a piece of infrastructure; it is a living landmark that plays an active role in the daily life of Duluth. The bridge's horn, composed of two Westinghouse Airbrake locomotive horns, is an integral part of the maritime culture. The customary horn-blowing sequence, known as the Captain's Salute (long-short-short), is exchanged between the bridge and passing ships, adding a touch of tradition to the modern operation.

One of the most poignant moments involving the bridge occurs on November 10 each year, the anniversary of the sinking of the SS Edmund Fitzgerald on Lake Superior. The bridge exchanges a special salute with the SS Arthur M. Anderson, the last vessel to have contact with the Fitzgerald. This master salute, consisting of a long-long-long-short-short sequence, honors the memory of the Fitzgerald and its crew, underscoring the bridge's deep connection to the maritime history of the Great Lakes.

Visiting the Aerial Lift Bridge

A visit to the Aerial Lift Bridge is a journey through time and technology. As you stand at the base of this towering structure, you can feel the hum of its machinery and the weight of its history. The bridge's intricate lattice of steel beams and cables is a testament to the ingenuity and determination of the engineers and workers who brought it to life.

For the best experience, take a stroll along the waterfront and watch as the bridge lifts to allow a ship to pass. The sight of the massive span rising gracefully into the sky is both exhilarating and humbling. Don't forget to listen for the horn signals and try to spot the bridge operator in the control house, orchestrating the movements of this mechanical giant.

Nearby, the United States Army Corps of Engineers maintains a maritime museum that offers further insights into the history of the bridge and the port of Duluth. The museum features exhibits on shipbuilding, navigation, and the economic impact of the Great Lakes shipping industry, providing a comprehensive understanding of the region's maritime heritage.

A National Historic Landmark

The Aerial Lift Bridge was added to the National Register of Historic Places on May 22, 1973, recognizing its significance as a pioneering piece of engineering and a vital part of Duluth's history. In 2017, it was designated a National Historic Civil Engineering Landmark by the American Society of Civil Engineers, further cementing its status as an engineering icon.

In conclusion, the Aerial Lift Bridge in Duluth, Minnesota, is more than just a bridge; it is a symbol of innovation, resilience, and community. Its storied past and continued operation make it a fascinating destination for visitors of all ages. Whether you're admiring its architectural beauty, learning about its history, or simply enjoying the view of ships passing beneath, the Aerial Lift Bridge offers an unforgettable experience that captures the spirit of Duluth and the enduring legacy of its maritime tradition.