The Kinzua Viaduct was a bridge built by 40 workers in just 94 days from tibular wrought iron columns.
The Kinzua Viaduct was a bridge built by 40 workers in just 94 days from tibular wrought iron columns.
From the late 19th century and well into the 20th century, the Kinzua Viaduct was vital to locomotives traveling through northwestern Pennsylvania to reach McKean County’s supply of coal, timber and oil. The viaduct was built over the Kinzua Gorge to avoid having to construct an additional 8 miles of track over rough terrain.
Construction began in 1881 and upon completion in 1882, it became the highest and longest railroad viaduct in the world, gaining recognition by some as the “eighth wonder of the world.”
Even after it closed to freight traffic in 1959, the viaduct, which is a type of bridge that passes over natural features such as valleys, remained a landmark for decades. Tourists took rides on excursion trains starting in the 1980s, and the viaduct was on track for safety restoration in the 2000s when a worst-case scenario occurred.
The Kinzua Viaduct, located 115 miles northeast of Pittsburgh, was built by 40 workers in just 94 days and built from tubular wrought iron columns. It was operated by the Erie Railroad and measured 301 feet high and 2,053 feet long, according to the Allegheny National Forest Visitors Bureau. However, at the turn of the century, massive locomotives – which were 85 percent heavier – led to the viaduct needing reinforcement, according to the American Society of Civil Engineers.
Reconstruction of the viaduct began on May 24, 1900, and lasted for four months. The revamped viaduct was made from 3,358 short tons of steel and required up to 150 workers to put in about 10 hours of work a day. The middle tower of the viaduct was demolished and only took seven days to reconstruct. The viaduct reopened on Sept. 25, 1900.
The Kinzua Viaduct remained open for decades to both steam and diesel locomotives. By the 1950s, the viaduct had aged to the point where new weight and speed limits were issued – resulting in steam engines having to stop at the viaduct to let one train cross at a time. The last steam engine crossed its tracks in October 1950, according to Explore PA History.
The viaduct was retired in 1959 and remained unused for years. The original plan called for the viaduct to be scrapped, but once its historic value was recognized the viaduct was sold to the Commonwealth of Pennsylvania in 1963 for public recreation use.
The site became a state park in 1970 – known officially as Kinzua Bridge State Park – and was added to the National Register of Historic Civil Engineering Landmarks in 1977. Excursion trains for tourists began to run in 1987 and lasted 15 years before the area was closed due to structural concerns. The last train went over the viaduct in 2002.
During an inspection in 2002, engineers found sections of steel had been rusted through, according to the Pennsylvania Department of Conservation and Natural Resources (DCNR). Engineers were also concerned about the possibility of high winds causing lateral pressure on the viaduct – which could shift the center of gravity and result in the viaduct collapsing. As a result, the DCNR decided to end excursion trains and ban pedestrian traffic.
As it turned out, the engineers were dead on about the risks of high winds. On July 21, 2003, a powerful tornado touched down and wiped out the structure in a flash.
Efforts were made to stabilize the viaduct after it closed. In February 2003, emergency repairs and construction began and were still ongoing in July 2003 when the disaster unfolded.
At about 3 p.m. EDT on that fateful July day, construction workers were continuing the viaduct’s restoration when it began to rain. The construction supervisor told his crew to pack up early for the day due to an incoming storm.
The workers were instructed to head to a nearby motel to ride out the storm, but harsh weather began before many made it down the road from the viaduct.
“As we were leaving, the wind started to pick up and by the time we got to the park entrance, it was blowing hard and trees were falling all around us,” construction crewmember Kenneth Feille wrote in his eyewitness account.
Many became stuck as they attempted to continue down the road toward the motel.
“As we were leaving we came to the end of the road. We got stop [sic] by falling trees, heavy rain. You couldn’t even see in front of you,” construction worker Shawn McVey wrote in his eyewitness account.
Some workers caught in the storm noted their truck rocking back and forth and a nearby guard shack being lifted.
“As soon as it came it was gone. We then ran down over the trees and valley and noticed the viaduct was down,” Kevin Helmandollar, another construction crew member, wrote in his eyewitness account.
What the crew didn’t know was that at about 3:20 p.m. EDT, a tornado formed about 1 mile from the structure and continued for about 2.5 miles. The tornado’s path of damage included the viaduct.
In less than 30 seconds, over a century of history collapsed as the tornado destroyed most of the viaduct with winds over 90 mph. The tornado’s vortex impacted the viaduct from the east and south, causing it to collapse in three phases.
More than half of the spans and 11 supporting towers collapsed from the tornado. Remarkably, three towers were picked up from their foundations, moved slightly and set back down intact, held together by just the railroad tracks. Those three towers eventually collapsed due to the twister’s strong winds. The tornado was rated an F1 with a max wind speed of up to 112 mph. No fatalities or injuries were reported as a result of the tornado.
An investigation attributed the collapse to badly rusted iron base bolts that held the bases of the towers to concrete anchor blocks. The entire structure had oscillated laterally up to five times before the base bolts failed.
Following the collapse, a public discussion took place for years about the future of the site. Rebuilding the viaduct would have cost an estimated $45 million, according to Society for Industrial Archeology. In 2005, the DCNR proposed constructing a new observation deck, known as the skywalk, and a visitor center. The plan included a hiking trail that would take visitors to a spot where they could view the fallen towers.
The skywalk was constructed using six of the steel towers that remained after the tornado, according to the Allegheny National Forest Visitors Bureau. The skywalk, which opened in 2011 to pedestrians, is situated over 200 feet above the valley floor and extends over 624 feet into the Kinzua Gorge.
The portions of the viaduct that were damaged by the tornado remain on the valley floor, according to Penn Live. The hiking trail to the bottom provides visitors with an up-close look at the destroyed viaduct, an opportunity for folks to get a sense of how the wondrous structure and “engineering masterpiece” once towered over the valley.
Produced in association with AccuWeather
