Home >  Local News

Wednesday, July 23, 2003

By Lillian Thomas, Post-Gazette Staff Writer

The Kinzua Viaduct had survived many travails before a tornado sent its center section toppling into the floor of the Kinzua Valley.

It was conceived as an attention-getting engineering marvel by Gen. Thomas Kane, who owned a coal company and wanted to draw people to the area as well as move his coal across the deep gorge.

The original bridge was built in 94 days in 1882 by 40 men, who used each completed tower as a platform for the next one. The finished viaduct had 20 towers supporting the 301-foot-high span that ran about 2,100 feet across the gorge and at the time was the tallest viaduct in the world. It was the fourth tallest before its fall.

"This was a unique structure," said Eugene Comoss, chief engineer for the state Department of Conservation and Natural Resources. "The design method was fairly unusual for those days. In trade publications at the time, the design engineer was criticized by his peers. Typically a bridge that high and that wide has cross bracing [braces that resemble the letter X]. He just used horizontal members. Some engineers at the time thought it would fail."

It took 121 years for them to be proved right.

The original bridge was iron; in 1900, that structure was demolished and replaced by a duplicate design of steel.

Passenger service ended in 1949, and the Erie Railroad abandoned the line in 1959 because it was too expensive to maintain. The viaduct was sold for scrap, but Nick Kovalchick, the man who bought it, changed his mind and sold it to the state.

Kinzua Bridge State Park was created in 1963. In 1986, the Knox & Kane Railroad began running a steam locomotive to give tourists a look at the astonishing structure and the view from its span. The park drew up to 100,000 visitors a year.

Last year, though, engineers determined that the bridge was badly deteriorated and vulnerable to high winds. Though it was designed to flex under wind pressure, rust and years had taken their toll.

"After approximately 100 years of aging, a lot of things that would allow it to move were rusted or frozen solid from rust," said Comoss. "The structure loses its flex and becomes more rigid."

The state closed the bridge to rail traffic in June 2002, then later in the summer to pedestrian traffic .

In February, crews started a $10 million renovation project. The towers they had completed all stood firm in the wind, "so at least there's some validation to our work," said Comoss.