Excessive heat on the train tracks derailed a BART train near Concord earlier this week, officials said.
About 50 passengers had to be evacuated around 5:30 p.m. Tuesday after a Bay Area Rapid Transit train derailed near Hastings Drive and David Avenue.
According to firefighters, several people reported minor injuries. One person who complained of back pain was taken to hospital, BART officials said.
The train derailed amid a Bay Area heatwave that sent temperatures soaring into triple digits.
“Our initial assessment is that heat played the primary role in the partial derailment by causing a bend in the rail,” BART said in a statement.
Temperatures on the track exceeded 140 degrees — about 35 degrees above ordinary rail operating temperature — BART spokesman Chris Filippi told the San Francisco Chronicle. Tracks can become misaligned when rail temperatures reach or exceed 20 degrees above neutral operating temperatures, Filippi said.
Derailments caused by excessive heat are rare but not unheard of. A 19-car freight train derailed in Tulare County after extreme heat caused the track to buckle in 2017. Officials reported similar causes when a freight train derailed in Big River near the California-Arizona border in 2020.
The transit system could not confirm whether this was the first heat-related derailment, the Chronicle reported. There is no mention of heat contributing to derailments on BART tracks, according to agency records, which date back to 2005.
Railroads across the country could become more vulnerable as the frequency and intensity of heat events increase, according to a 2019 study in Transport Policy. The study found that by 2100, railways across the country could suffer $25 billion to $60 billion in damage due to heat and climate change.
After the BART train derailment, transit officials began running single-track trains between Pleasant Hill and Concord. The scene was cleared Wednesday morning after about 70 BART employees worked through the night to clear the way for morning commuters, the transit system said in a statement.