Niagara Falls Suspension Bridge

The Niagara Falls Suspension Bridge was the world's first working railway suspension bridge. It spanned 825 feet (251 m) and stood 2.5 miles (4.0 km) downstream of Niagara Falls from 1855 to 1897. Connecting Niagara Falls, Ontario to Niagara Falls, New York (the two cities assimilated the towns at the ends of the bridge by 1892), the bridge carried mixed traffic on its two decks across the Niagara River; trains crossed over the river by way of the bridge's upper deck while pedestrians and carriages used the lower. As the bridge was the result of a collaboration of two companies from two countries, it was also known by its American name, the International Suspension Bridge. The bridge had other names including the Niagara Railway Suspension Bridge and Niagara Suspension Bridge, but the most common and definitive was simply the Suspension Bridge.

The Suspension Bridge was part of Canadian politician William Hamilton Merritt's vision to promote trade within his country and with its neighbor the United States. When Merritt and company invited the engineering community to bid for the bridge project, they encountered heavy criticism. Many bridge builders, and the general public, did not believe a suspension bridge could allow the safe passage of trains. Nonetheless, the bridge companies engaged several well-known civil engineers to build and maintain the bridge. Charles Ellet, Jr. was first hired to construct the bridge. Using a line laid by a kite across the 800-foot (240 m) chasm, he built a temporary suspension bridge in 1848 as the first part of his plan. Not long after, Ellet left the project after a bitter financial dispute with the bridge companies. A three-year hiatus followed before the companies hired John Augustus Roebling to complete the project. Roebling used Ellet's bridge as scaffolding to build the double-decked bridge. By 1854 his bridge was nearly complete, and the lower deck was opened for pedestrian and carriage travel. On March 18, 1855, a fully laden passenger train drove across the upper deck at 5 miles per hour (8.0 km/h), and officially opened the completed bridge.

As a border crossing between Canada and the United States, the Suspension Bridge played significant roles in the histories of the Niagara region and the two countries. Three railway lines crossed over the bridge, connecting cities on both sides of the border. The Great Western Railway, New York Central Railroad, and New York and Erie Rail Road differed in the width of their tracks; the bridge used a triple gauge system to conserve space, overlapping two tracks on top of each other and using a rail of each to form the third track. The railroads brought a large influx of trade and tourists into the region around the Niagara Falls. Growing quickly from the traffic, the small towns at the ends of the bridge were integrated into the Niagara Falls cities. Many tourists flocked to the bridge to view the acclaimed marvel of engineering, as well as tightrope-walking daredevils who performed against the backdrop of the falls. In the time leading to the American Civil War, the Underground Railroad helped slaves in the United States escape across the Suspension Bridge to freedom in Canada. After the war, the bridge became a symbol of inspiration to Americans, encouraging them to rebuild their country and pushing them to quickly industrialize their nation.

Throughout its years of service, the Suspension Bridge stood strong and allowed thousands of passengers and trains to pass over it safely. Its success proved that, contrary to general opinion, a safe and operational railway suspension bridge was tenable, and allayed concerns induced by the 1854 collapse of the Wheeling Suspension Bridge. Slowly decaying, the bridge's wooden structures were replaced with steel and iron versions by 1886, and the renovated bridge was stronger, capable of bearing a heavier load. By the end of the 19th century, the weight of trains had increased greatly and far exceeded the maximum capacity of the bridge. The Suspension Bridge was finally replaced by the Steel Arch Bridge, which was later renamed the Whirlpool Rapids Bridge, on August 27, 1897. When the Suspension Bridge was dismantled, its wire cables were found not to have noticeably degraded, a testament to its strength and design.