August 2007

Mount Jewett PA - Kinzua Bridge

Our destination was the historic Kinzua Bridge that once spanned the Kinzua Gorge carrying coal mined south of the gorge to areas in the north.  It lies just north of U.S. 6 in PA and the entrance to the park is just east of Mt. Jewitt PA.  When built in 1882, Kinzua Viaduct was the highest railroad bridge in the world. It was constructed as an alternative to laying an additional eight miles of track over rough terrain along the line leading to McKean County’s coal, timber and oil lands.  Built of iron, the original viaduct was 301 feet high, 2,053 feet long, and weighed 3,105,000 pounds.  By 1900, it became necessary to rebuild the entire structure with steel to accommodate heavier trains.  That May, about 100 to 150 men working ten-hour days completed the job in 105 days.  The new steel viaduct had the same measurements, but now weighed 6,715,000 pounds.  Freight traffic discontinued in June of 1959.  In 1963, Governor William Scranton signed a law that created Kinzua Bridge State Park.  The park officially opened in 1970.  In 1977, Kinzua Viaduct received national recognition when it was placed on the National Register of Historic Civil Engineering Landmarks.  Beginning in 1987, excursion trains traveled from Kane, PA through Allegheny National Forest, stopping on Kinzua Viaduct before returning to its point of origin.  Although the bridge received periodic inspections, it was not until a February 2002 DCNR inspection that engineers decided that the structure needed a full-scale inspection.  In June, DCNR barred excursion trains from the bridge.  As the inspection continued, engineers found that sections of steel were rusted through.  In August, the bridge was closed to all traffic, including pedestrians.  Engineers determined that high winds could create lateral pressure on the bridge.  The wind hitting the bridge could shift the center of gravity, increasing the weight on one side. Such an event could send the whole bridge crashing to the bottom of Kinuza Gorge.  Beginning in February, 2003, W. M. Brode Co. of Newcomerstown, Ohio, a national leader in railroad bridge construction and repair, began working to restore Kinzua Viaduct.  On Monday, July 21, 2003, at approximately 3:15 p.m., an F1 tornado (wind speed 73 – 112 mph) struck the side of Kinzua Viaduct.  Eleven towers from the center of the bridge were torn from their concrete bases and thrown to the valley floor.  Fortunately no one was seriously injured. 

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