Overview
- A $1.5 million Parsons review spanning more than 15,000 hours found no single root cause and called for continued analysis, a conclusion board members described as frustrating but candid.
- Nine major interruptions between West Oakland and Civic Center included three in the Transbay Tube, with documented insulator flashovers on Sept. 29, Oct. 20, Nov. 25 and Dec. 8.
- Contributing factors cited included power fluctuations, equipment sparks and insulator failures, with dust, humidity, puddles and stray items like aluminum cans or Mylar balloons increasing arcing risks.
- BART has begun cleaning and replacing insulators, removing debris, restoring Transbay Tube crossbonds removed in 2020 and activating additional sensors, with targeted high-pressure washing underway in San Francisco tunnels.
- Officials provided no timeline for a final determination, and the agency faces a projected $350–$400 million deficit as emergency funds near exhaustion.