A Muni train derailed around 7:30 a.m. between Castro and Forest Hill stations on the outbound side, causing no injuries, said San Francisco Municipal Transportation Agency spokesman Judson True.

The second truck, the second set of wheels, of the second car of an L train derailed in the Twin Peaks Tunnel, and passengers were then transported by a light rail vehicle, True said.

He said that the cause of the accident might be a problem with the communication cable in that part of the tunnel, according to the SFMTA report.

Inbound service was not interrupted, but outbound trains only ran from Embarcadero to Castro stations, and West Portal Station and onwards. True said over a dozen shuttles were provided from Castro Station to West Portal Station, stopping at all the usual subway stops.

"We are doing everything to get people to work this morning," True said.

True said that the outbound service should resume today.

"We don't have any estimate now," True said, "but it will take a little while."

Several students were affected by the delays caused by the accident and complained about Muni's reliability.

"I come here from Vallejo every day. It's stressful," said Jasmine Neri, an English major. "You can't rely on public transportation and it's San Francisco so you can't just drive yourself around."

Neri, 19, was trying to get to a 9 a.m. Karate class but had to get on the F car at Powell Station, then take a shuttle bus from Castro Station to West Portal Station, then the regular M train to school.

A medical student from City College of San Francisco, John Gutzat, said he was probably going to miss his first class.

"Its just bodybuilding so it's nothing serious, but I only have three absences before I'm dropped," said the 20-year-old.

"I think it's bad for all the students because some people just know a specific route, and I think Muni should provide different options in case something like this happens again," said Holly Ly, a psychology major, who was trying to get to her 9:35 a.m. law class.