The president of San Francisco's transit workers union says a light-rail operator blacked out just before his San Francisco Municipal Railway train crashed into a parked train Saturday, injuring 47 passengers.
Union president Irwin Lum told The Associated Press on Monday that a "medical condition" was to blame for the driver's loss of consciousness.
Federal investigators reported Sunday that the driver, who has not been named, had turned off the train's automatic controls moments before the collision.
Lum said that drivers 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 the 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 OK based on 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 in the front of the train, and part of it was pushed into him," said San Francisco Fire Lt. Ken Smith.
The operator wasn't following normal procedures, a National Transportation Safety Board investigator said Sunday.
The driver had put the train into manual mode before the 2:50 p.m. crash at the West Portal Station. If the train had been on automatic mode when it pulled into the station the crash wouldn't have happened, said Ted Turpin, the lead investigator for the NTSB, which is spearheading the investigation.
The driver never engaged the emergency brake and an investigation has so far turned up no mechanical problems on the train, Turpin said.
The L-Taraval train was traveling at 20 to 23 mph when the crash happened on the outbound platform of the station.
Investigators said it appears the operator of the L-Taraval train switched from auto to manual while he was still inside the tunnel, and 24 seconds later he struck the K-Ingleside line, Turpin said at a Sunday news conference.
It is not Muni procedure to switch to manual at that point. The drivers are supposed to wait until they are in the station, he said.
Elena Wong was on the stopped train and says passengers went flying on impact.
"It felt like a movie. Glass shattered everywhere. There were emergency noises going off. Two people were lying on the ground crying. There was blood a on girl. When she turned around she was completely covered in blood," Wong said.
Wong was on of the passengers who was treated and released Saturday night.
"I was sitting. I went flying forward and hit a metal bar and then went flying back --- absolute shock," Wong said as she left the hospital.
A woman who said she saw the crash told NBC Bay Area reporter Monte Francis that she noticed the L train operator who hit the stopped train had his head down at the time. She said he could have been passed out, or asleep or not paying attention. She said that part was not clear, but said he was not looking straight ahead as he "barreled into the stopped train."
Another woman told Francis she saw the driver making gestures as if to say he could not stop the train.
The NTSB also said Sunday that the L-Taraval train has been inspected and no brake or other mechanical problems were found. Investigators are also looking at the signal system to make sure everything was working that controlled the train. In addition they are reviewing video footage from cameras that were in the station and on the train.
Turpin said they are also looking into cell phone records to see if the operator was talking on his phone or texting when the crash happened.
"We always gather cell phone information," he said.
The driver, who was drug tested after the crash, started as a bus driver with Muni in 1979. He has been a light rail operator since 2007.
The San Francisco Municipal Transportation Agency is providing information to the NTSB for its investigation. Other agencies investigating the crash are the California Public Utilities Commission and the Federal Transit Authority.
SFMTA Director Nathaniel Ford said Muni officials are concerned about the people who were injured. Once the investigation is complete Muni will make any necessary changes to ensure this doesn't happen again, he said.
"We do not take these situations lightly," Ford said. "We are in the midst of a very in-depth investigation."
The on-scene phase of the investigation generally lasts between three to five days, NTSB spokesman Peter Knudson said. The full investigation could take up to a year.
Light rail vehicles resumed service at the West Portal Station about five hours after the crash.
Several people, including the operator of the L-Taraval train, suffered serious injuries. At least 40 others were transported to hospitals with minor-to-moderate injuries, Muni spokesman Judson True said. No deaths were reported.
The four people most seriously injured in the crash remained in stable condition at San Francisco General Hospital, said Judson True, spokesman for the San Francisco Municipal Transportation Agency.
Scott Aguiar, a cafe manager, said the crash was the hot topic in the quiet little shopping district.
"People are talking about how Muni is probably going to raise the fares again because of the upcoming lawsuits from the crash," he said.
The Muni crash is the latest in a series of mass transit accidents nationwide in recent months.
NBC Bay Area reported the crashes are leading to new concerns among federal officials over the safety of what are considered an aging transit systems.
Bay City News Contributed to this report.