Bridging the Florida Keys: The Fascinating History of the Seven Mile Bridges

The Seven Mile Bridges, both the historic Old Seven Mile Bridge and its modern replacement, are enduring symbols of engineering ingenuity and perseverance in the Florida Keys. Their histories include triumphs and tragedies, such as the devastating Moser Channel fire on the Old Bridge.

The Old Seven Mile Bridge

• Part of the Overseas Railroad: Built between 1909 and 1912, the Old Seven Mile Bridge was an integral part of Henry Flagler’s Florida East Coast Railway, connecting Knight’s Key (now Marathon) to Little Duck Key and enabling rail travel to Key West.
• Engineering Marvel: At nearly 6.8 miles long, the bridge was a groundbreaking feat of early 20th-century engineering. Its swing span at Moser Channel was a key feature, allowing large ships to pass through.
• The Moser Channel Fire: On March 2, 1981, tragedy struck when a maintenance truck from Florida Keys Aquatic towing a backhoe headed east across the bridge. The backhoe came loose, jolting the dirt bucket above the bridge’s 15-foot-5-inch clearance. The truck struck an overhead steel girder, rupturing a propane tank and igniting gasoline tanks. The resulting explosion sent flames 200 feet into the air. The bridge tender’s wooden quarters, perched within the swing span framework, were incinerated. Peter Charles Fancher, working a 12-hour shift and one week from retirement, was tragically burned to death. The fire highlighted the structural vulnerabilities of the 72-year-old bridge, which was already one year from closure.

Why the Old Bridge Was Retired

The Old Seven Mile Bridge had become outdated by the 1970s. Its narrow lanes, weight restrictions, and aging infrastructure could no longer safely support modern vehicles. The catastrophic fire at Moser Channel underscored the need for a safer, more robust replacement.

The New Seven Mile Bridge

• Modern Construction: Built between 1979 and 1982, the new Seven Mile Bridge was designed to meet the needs of contemporary traffic. Made entirely of reinforced concrete, it was engineered to withstand hurricanes and heavy use.
• Improved Features: The new bridge, at 6.79 miles long, is wider, taller and sturdier than the original, with two lanes and no need for a swing span, ensuring uninterrupted travel.
• A Scenic Landmark: Renowned for its stunning views of the turquoise waters and surrounding islands, the new bridge is celebrated as one of the world’s most scenic drives.

Preservation of the Old Bridge

Though most of the Old Seven Mile Bridge was retired, a 2.2-mile section connecting Marathon to Pigeon Key was preserved. This segment has been restored as a pedestrian and bicycle path, preserving its historical and recreational value for future generations.

Legacy of the Seven Mile Bridges

The Old Seven Mile Bridge stands as a testament to early 20th-century innovation and the human spirit. The Moser Channel fire, a tragic chapter in its history, marked the end of its era but also reinforced the need for progress. The new bridge carries forward its legacy, providing a vital link for the Keys and symbolizing resilience and connection.