Witnesses described a chaotic scene following the crash, which occurred just before 3 p.m. when an L Taraval smashed into the back of a K Ingleside train near the station’s boarding platform, said Muni spokesman Judson True.

The impact of the crash shattered the front window of the L train and crumpled its steel nose. The shattered windshield, apparently made of safety glass, stayed in place. Both trains were headed in the outbound direction.

The most seriously injured was the driver of the L train, who was conscious when paramedics arrived, said Deputy Fire Chief Pat Gardner. Three riders were also seriously injured, authorities said.

About 20 people suffered moderate injuries and were taken to local hospitals in ambulances, Gardner said. The remaining injuries were not serious, and the victims were able to walk to a Muni bus, which took them to the hospital.

“This is probably one of the largest we’ve ever seen (in recent years),” Gardner said of the crash, referring to the sheer number of people injured.

It was the latest in a spate of mass transit accidents around the country.

Last month, a Metro commuter train slammed into the rear of another subway train near Washington, D.C., killing nine riders and injuring scores of others. In May, 49 people were injured when a Boston trolley car crashed into another.

Those accidents, as well as the violent collision of a commuter train with a freight train last September in Chatsworth (Los Angeles County), which killed 20 people, have prompted federal safety investigators to raise concerns about the nation’s aging rail cars, tracks and signal systems.

Witnesses of Saturday’s Muni crash said several people with head and neck injuries were loaded onto gurneys and taken away in ambulances.

Linda Burke, a 58-year-old West Portal resident, and her husband 59-year-old Mike Burke, were walking home from watching “Harry Potter and the Half-Blood Prince” at a nearby theater and were across the street when the crash occurred.

They said the K train appeared to be stopped when the rear train slammed into it.

“It sounded like a bomb or an explosion; we looked up and said, ‘What the heck was that?” Linda Burke said. “There was this huge plume of dark smoke that came out from the back of the street car (that was hit).”

She said there was screaming and yelling; some passengers fell to the floor of the Muni trains. People came running from nearby businesses to help, including one who handed out napkins to bleeding victims.

The Burkes said the sound of the collision and the resultant damage suggested the K train had been going faster than it usually would have in the station.

“He must have been flying the way the front end caved in,” said Mike Burke.

West Portal resident Dan Dudum, 48, was two doors down inside the Philosophers Club, a bar.

“It shook the building – all of a sudden the building went like that,” he said, gesturing with his hand from side to side, “and I said, ‘Hey, something’s not right here.’”

“I didn’t know what it was, but it was loud,” Dudum said, adding that firefighters arrived seven minutes after the crash.

Muni personnel in yellow fluorescent vests swarmed the scene afterward, investigating the accident alongside more than 10 police officers and 40 firefighters and paramedics who blocked off the area with yellow police tape. Dozens of people stopped near the station – located at the end of the neighborhood’s commercial district – to gawk at the crash.

True said officials have not determined why the trains collided.

“We will look at everything from mechanical issues to human error,” he said, adding that the train’s speed will be part of the investigation.

West Portal resident Laurel Paul, who was in the nearby public library when the accident occurred, said she and her son rushed outside after hearing the crash.

“There was a huge crowd gathering outside the station,” she said. “I’ve been riding Muni since the 1970s, and I’ve never seen a train crumpled in the front with a shattered windshield.”

The crash forced Muni to halt service in both directions in the area and prompted authorities to shut down the intersection of West Portal Avenue and Ulloa Street. Claremont Street, located a block off West Portal Avenue, is also shut down.

Buses are providing service between the West Portal and Castro stations and between West Portal and the western side of the city.

from: sfgate.com