A broken rail caused a train derailment that collapsed a bridge over an interstate highway in Colorado, killing a truck driver and blocking the road for days, federal authorities said Tuesday, based on their preliminary investigation.
Officials will investigate how the rail broke and why warning systems did not alert crews to the condition of the track, the National Transportation Safety Board said in a news release.
The steel bridge built in 1958 collapsed Sunday when 30 cars from a BNSF train hauling coal derailed while crossing over Interstate 25 north of Pueblo.
The 60-year-old driver of a semitrailer truck that was passing beneath the bridge was killed. I-25, the main north-south route through Colorado, is expected to remain closed for several more days as crews clear away piles of coal and other debris.
Broken rails and other track problems are a leading cause of derailments, according to federal accident data.
The NTSB has previously recommended that railroads install more automatic monitoring systems that can detect problems with tracks early on and prevent accidents. The agency repeated its call for those systems in July in response to a fatal Amtrak derailment along BNSF-owned tracks in northern Montana two years ago.
It was not immediately known whether the track where Sunday's derailment occurred had such a system. NTSB spokesperson Sarah Taylor Sulick said that was under investigation.
Representatives of BNSF did not immediately respond to emailed questions.
There is no reason to believe the derailment was sabotage, Sulick said.
"They will be pulling maintenance records. They'll be interviewing people involved. They'll be talking to the railroad. They'll be talking to the state," Sulick said.
Federal investigators late Monday approved cleanup work along I-25 after largely completing their evidence collection where the BNSF coal train derailed.
A nine-mile stretch of I-25 — used by 39,000 to 44,000 vehicles daily — was shut down. Traffic was being detoured around the derailment site and through the town of Penrose, almost 30 miles west of Pueblo.
Meanwhile, the bridge's ownership remained unclear two days after the accident.
Railroad companies typically own the bridges that trains use. However, BNSF said the steel girder bridge that collapsed onto I-25 was owned by the state.
Colorado officials initially said the bridge was the property of the railroad but later backed off that claim.
Officials were still combing through records Tuesday, trying to determine ownership, said Matt Inzeo, of the Colorado Department of Transportation.
Hundreds of tons of coal and mangled railcars that landed on I-25 were expected to be cleared from the road by Wednesday afternoon, officials said. After that, officials will be able to assess how badly the road is damaged and what repairs are needed.
There were more than 12,400 train derailments in the U.S. in the past decade, or more than 1,200 annually, according to Federal Railroad Administration data that's based on reports submitted by railroads.
Pressure for the industry to improve safety has grown in recent months following a February derailment of a train hauling toxic chemicals that triggered evacuations in Ohio and Pennsylvania.
Since 1976, at least 111 railroad accidents have been caused by bridge failures or bridge misalignments, according to an Associated Press review of derailment reports submitted by railroads to the Federal Railroad Administration. That's just over two accidents annually on average.
President Joe Biden had been scheduled to visit a wind energy company in Pueblo the day after the accident but postponed the trip at the last minute to focus on the growing conflict in the Middle East.
Sunday's accident follows a railroad bridge collapse in June along a Montana Rail Link route in southern Montana that sent railcars with oil products plunging into the Yellowstone River, spilling molten sulfur and up to 250 tons of hot asphalt. The accident remains under investigation.