Federal investigators from Los Angeles are headed back home tonight after wrapping up the initial investigation into the weekend crash of two Muni trains in San Francisco that left dozens hurt.
Before heading out, investigators said they are still focusing on human error as the cause after finding no indication of mechanical or systems failure.
The National Transportation Safety Board said Wednesday that the operator of the San Francisco Municipal Railway train responsible for Saturday's collision told its investigators that he blacked out before the crash. The driver made the same claim to his union earlier in the week.
Witnesses told NBC Bay Area they noticed the driver with his head down the moments before his train smacked into a stopped train at the West Portal Station.
The first video of the crash was also released Wedneday. The videos show the south-bound train stopped inside the West Portal tunnel when a second train crashed into it from behind.
The NTSB says it found no problems with the train's brakes or any other mechanical issues that would have led to the accident. Investigators still are reviewing 61-year-old driver Henry Gray's health history.
Federal investigators reported Sunday that the driver had turned off the train's automatic controls moments before the collision, adding that is not following normal procedures.
Union president Irwin Lum said all Muni drivers are under pressure to keep their trains running on time turn off the controls before entering the West Portal station to speed loading and unloading.
The automatic controls are set to stop trains approaching West Portal in the tunnel until the train ahead leaves the platform, Lum said. But for years, he said, drivers pressured to improve on-time performance would manually move their trains out of the tunnel and directly behind the stopped train ahead.
"Basically it was understood that it was okay based of the fact that passengers were complaining about long waits getting to the platform," Lum said.
The operator was pinned inside his damaged compartment after his westbound train struck the end of the other train at the platform.
He was one of four people who were seriously hurt in the crash.
If it turns out that Muni is liable for the accident, the transit agency could have a significant legal challenge on its hands.
NBC Bay Area has learned some of the injured passengers have already contacted lawyers.
Douglas Saeltzer is an attorney who has multi-million dollar cases now pending against Muni for other reasons. He said cameras on board the light rail train should clearly show if the operator was at fault.
He also said that if a court finds that the city was liable for the West Portal crash, it could cost the transit agency tens of millions of dollars.
"If one or two of the victims have severe injuries that prevent them from ever working again or from taking care of their children," Saeltzer said, "then one case alone could be $5 or $10 million."
Ironically, just last week, the Municipal Transit Agency board decided to start the process of buying accident insurance after it paid $21 million to the family of a four 4-old-girl who was killed in a Muni accident in 2003.
But as it stands, the agency still has not purchased that insurance and legal claims are still paid out of Muni's budget.
Saeltzer said there are circumstances that would help Muni avoid liability in this case. If the train operator suffered some kind of medical emergency, the agency would not be liable but if the operator simply made a mistake, they'd have to pay.
"Muni owns the actions of its employees who are on the job," Saeltzer sais, "and if the operator made a mistake then Muni is responsible for its employee."
Last fiscal year, the MTA paid out nearly $20 million in legal claims and the agency is currently dealing with a $130 million budget shortfall.
