The Kinzua Bridge or the Kinzua Viaduct (, ) was a railroad trestle that spanned Kinzua Creek in McKean County in the U.S. state of Pennsylvania. The bridge was 301 feet (92 m) tall and 2,052 feet (625 m) long. Most of its structure collapsed during a tornado in July 2003. Billed as the "Eighth Wonder of the World", the wrought iron original 1882 structure held the record for the tallest railroad bridge in the world for two years. In 1900, the bridge was dismantled and simultaneously rebuilt out of steel to allow it to accommodate heavier trains. It stayed in commercial service until 1959, when it was sold to a salvage company. In 1963 the Commonwealth of Pennsylvania purchased the bridge as the centerpiece of a state park. Restoration of the bridge began in 2002, but before it was finished a tornado struck the bridge in 2003, causing a large portion of the bridge to collapse. Corroded anchor bolts holding the bridge to its foundations failed, contributing to the collapse. Before its collapse, the Kinzua Bridge was ranked as the fourth-tallest railway bridge in the United States. It was listed on the National Register of Historic Places in 1977 and as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers in 1982. The ruins of the Kinzua Bridge are in Kinzua Bridge State Park off U.S. Route 6 near the borough of Mount Jewett, Pennsylvania.
Original construction and service
In 1882, Thomas L. Kane, president of the New York, Lake Erie and Western Railway (NYLE&W), was faced with the challenge of building a branch line off the main line in Pennsylvania, from Bradford south to the coalfields in Elk County. The fastest way to do so was to build a bridge across the Kinzua Valley. The only other alternative would have been to lay an additional 8 miles (13 km) of track over rough terrain. When built, the bridge was larger than any ever attempted and over twice as large as the largest similar structure at the time, the Portage Bridge over the Genesee River in western New York. The first Kinzua Bridge was built by a crew of 40 from 1,552 short tons (1,408 t) of wrought iron in just 94 working days, between May 10 and August 29, 1882. The reason for the short construction time was that scaffolding was not used in the bridge's construction; instead a gin pole was used to build the first tower, then a traveling crane was built atop it and used in building the second tower. The process was then repeated across all 20 towers. The bridge was designed by the engineer Octave Chanute and was built by the Phoenix Iron Works, which specialized in producing patented, hollow iron tubes called "Phoenix columns". Because of the design of these columns, it was often mistakenly believed that the bridge had been built out of wooden poles. The bridge's 110 sandstone masonry piers were quarried from the hillside used for the foundation of the bridge. The tallest tower had a base that was 193 feet (59 m) wide. The bridge was designed to support a load of 266 short tons (241 t), and was estimated to cost between $167,000 and $275,000. On completion, the bridge was the tallest railroad bridge in the world and was advertised as the "Eighth Wonder of the World". Six of the bridge's 20 towers were taller than the Brooklyn Bridge. Excursion trains from as far away as Buffalo, New York, and Pittsburgh would come just to cross the Kinzua Bridge, which held the height record until the Garabit viaduct, 401 feet (122 m) tall, was completed in France in 1884. Trains crossing the bridge were restricted to a speed of 5 miles per hour (8.0 km/h) because the locomotive, and sometimes the wind, caused the bridge to vibrate. People sometimes visited the bridge in hopes of finding the loot of a bank robber, who supposedly hid $40,000 in gold and currency under or near it.
Reconstruction and service By 1893, the NYLE&W had gone bankrupt and was merged with the Erie Railroad, which became the owner of the bridge. By the start of the 20th century, locomotives were almost 85 percent heavier and the iron bridge could no longer safely carry trains. The last traffic crossed the old bridge on May 14, 1900, and removal of the old iron began on May 24. The new bridge was designed by C.R. Grimm and was built by the Elmira Bridge Company out of 3,358 short tons (3,046 t) of steel, at a cost of $275,000. Construction began on May 26, starting from both ends of the old bridge. A crew of between 100 and 150 worked 10-hour days for almost four months to complete the new steel frame. Two Howe truss "timber travelers", each 180 feet (50 m) long and 16 feet (5 m) deep, were used to build the towers. Each "traveler" was supported by a pair of the original wrought-iron towers, separated by the one that was to be replaced. After the middle tower was demolished and a new steel one built in its place, the traveler was moved down the line by one tower and the process was repeated. Construction of each new tower and the spans adjoining it took one week to complete. The bolts used to hold the towers to the anchor blocks were reused from the first bridge, which would eventually play a major role in the bridge's demise. Grimm, the designer of the bridge, later admitted that the bolts should have been replaced. The Kinzua Viaduct reopened to traffic on September 25, 1900. The new bridge was able to safely accommodate Erie's heavy 2-8-2 Mikados. The Erie Railroad maintained a station at the Kinzua Viaduct. Constructed between 1911 and 1916, the station was not staffed by an agent. The station was closed sometime between 1923 and 1927.
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