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The Kinzua Bridge or the Kinzua Viaduct ( or ) was a railroad trestle that spanned Kinzua Creek in McKean County in the U.S. state of Pennsylvania. Before its collapse in 2003, the bridge was tall and long. The bridge was originally built from iron in 1882 and was billed as the "Eighth Wonder of the World", holding the record as 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 and was sold to the Government of Pennsylvania in 1963, becoming 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 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. == First 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 coal fields in Elk County. The fastest way to do so was to build a bridge to cross the Kinzua Valley. The only other alternative to building a bridge would have been to lay an additional of track over rough terrain.〔 When built, the bridge was larger than any that had been 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 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 wide.〔 The bridge was designed to support a load of ,〔 and was estimated to cost between $167,000 and $275,000. On completion, the bridge was the tallest and longest 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, tall, was completed in France in 1884. Trains crossing the bridge were restricted to a speed of 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.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Kinzua Bridge」の詳細全文を読む スポンサード リンク
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