Early-morning exercisers and commuters near Tempe Town Lake were stunned to see a massive fire and thick smoke billowing from a rail bridge that has been a fixture in the city for more than 100 years.
Calls to 911 poured in shortly after 6 a.m. Wednesday as the Salt River Union Pacific Bridge turned into a fiery disaster scene. While the sequence of events was not yet clear Wednesday night, the cascade of dangers included a derailment, a fire and a bridge collapse.
Tim McMahan, a spokesman for the railroad, said a freight train had derailed and eight to 10 rail cars were on fire. The south side of the bridge collapsed and rail cars tumbled into an empty park below.
At a news conference later that day, Tempe Fire Chief Greg Ruiz said no one was injured in the fire. The train conductor was treated for smoke inhalation and one firefighter was transported to a hospital for dehydration and later released.
The bridge collapsed just feet from Tempe Beach Park and the town lake corridor, which are popular exercise and gathering spots.
“We’re very fortunate,” Ruiz said. “This was a very dangerous event.”
The cause is under investigation, but here’s what we know so far:
What was the train carrying?
Tempe’s Ruiz said he was told the Union Pacific train was made up of 95 cars.
Debris was seen falling into the water during the fire, but no cars ended up in the lake.
Three tank cars were on the ground under the bridge, according to Union Pacific. Two of the cars contained cyclohexanone, a colorless industrial chemical that is used as a solvent and in metal degreasing. A third car contained a rubber material, he said. Those three cars were not involved in the fire.
Union Pacific’s McMahan said Wednesday morning that none of the train cars were reported to be leaking, though at a news conference Wednesday afternoon the Tempe fire chief said there was a leak of cyclohexanone. He said the car was not leaking into the lake, but into a dry area.
Officials were working on containing the leak, he said.
Recent derailment on same bridge
The Salt River Union Pacific Bridge was built in 1912 and survived as floods destroyed the previous three truss bridges constructed at the same location. The bridge is primarily used by cargo trains.
About a month ago, on June 26, a Union Pacific train derailed 12 cars along the same bridge, damaging the rail ties. The line re-opened the following morning, according to Union Pacific. Tempe’s Ruiz said fire and medical personnel responded to that incident and “put out the fire that occurred with the rail ties. No rail cars were on fire during that event,” he said.
Tempe Fire Assistant Chief Andrea Glass described the June 26 incident as “very minor,” with a few rail ties on fire and slight damage to the rail itself.
It doesn’t appear the city alerted residents about the June 26 derailment. Three hours after the derailment, Tempe Police said on Twitter that Rio Salado Parkway would be closed for “railroad repair” for up to two days. The department didn’t mention the train had derailed.
Tempe Mayor Corey Woods was asked at a news conference Wednesday about the June derailment and whether he was concerned about two derailments happening within a month on the same bridge.
Woods, who was sworn in as mayor earlier this month, said he only became aware of the June derailment on Wednesday morning.
He said was still “actively learning about the earlier derailment” and couldn’t speak to that issue yet.
What caused the derailment?
Tempe Fire Department spokesman Brandon Siebert said the derailment may have led to the bridge collapse and the cars catching fire based on early 911 calls, he said. Callers described seeing “a derailment,” he said.
The National Transportation Safety Board will be investigating the derailment and are in the fact-gathering stage, said Terry Williams, a spokesman. The federal agency investigates civil aviation accidents as well as significant accidents for other modes of transportation.
“We are still in the very early stages of this investigation,” he said. “We would not be able to comment on anything that may have caused this accident.”
The Arizona Corporation Commission, which regulates railroad crossings in the state, sent a hazmat inspector, track inspector and a mechanical inspector to the accident on Wednesday, spokesman Nick Debus said.
The FBI will also be involved in the investigation, said Tempe Police Chief Sylvia Moir, adding that there is nothing early on that indicates the derailment was criminal.
Tempe Police are asking anyone who witnessed or may have information about the train derailment to call the department’s non-emergency number at (480) 350-8311.
Why did the bridge collapse?
A bridge failure, like the one at Tempe Town Lake, is very rare, said Anthony Lamanna, a bridge expert and programs chair of the Del E. Web School of Construction at Arizona State University.
Lamanna said the details of the accident will remain unknown until the NTSB investigation, but said “there’s a lot of potential reasons” for the collapse.
“Something caused it. Was it the train? Was it the train derailing? Was it the bridge failure that caused the train to derail?”
Lamanna said metal can fatigue over time, so that could have been an issue. Also, railroad tracks can sometimes fail in hot temperatures when the metal expands and sometimes tracks can buckle.
Union Pacific said the bridge was last inspected on July 9, though the results of that inspection were not available Wednesday.
Because the bridge is privately owned by the railroad company, Lamanna said he expects it would have been well maintained for business reasons and any issues would have been caught during an inspection.
But older bridges are susceptible to problems. Lamanna said bridges of that era were not designed with the back-ups and redundancies seen in modern bridges. Instead of multiple supporting beams, there may just be one, he said, so that if something happens, the span could collapse.
Is the water contaminated?
Ruiz of Tempe Fire said the fire department has fielded numerous questions about the derailment’s impact on water quality.
He said city officials are working with multiple agencies at the local, county, state and federal level to ensure concerns are addressed “as the situation continues to develop.”
He said he did not have specifics on any immediate impact.
Will the bridge be rebuilt?
The Tempe mayor was asked Wednesday whether the iconic bridge would be rebuilt, and who would pay for cleanup and rebuilding.
Woods said he can’t speak for Union Pacific but, “I think they would probably take a hard look at rebuilding it.”
As for who would pay for cleanup and rebuilding, he said, he “assumes” the company would pay those costs.
“We’ll have to have a conversation about that,” he said.
ASU’s Lamanna expects the bridge will be beyond repair because of the fire’s detrimental impact on the steel and the bridge’s structural damage, both of which will have to be thoroughly inspected.
“My educated guess would be that it’s very likely they’re going to have to replace the bridge,” he said.
Is Tempe Beach Park open yet?
Tempe Beach Park is closed until further notice as are surrounding roadways.
Woods, the Tempe mayor, asked people to stay away while cleanup is ongoing and the investigation is underway.
“We’re going to find out exactly what happened,” he said. “And we’re going to get the job done.
Reporters Alison Steinbach, Paulina Pineda and BrieAnna J. Frank contributed to this story.
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