7 injured after SF Muni trains collide along Embarcadero

SAN FRANCISCO, Calif., - Seven people were injured when two Muni light rail trains crashed into each other in San Francisco Wednesday afternoon. 

San Francisco Fire Department confirmed four people were transported to the hospital in stable condition and three others reported being in pain. 

The crash happened around 1:40 p.m. near Brannon Street and Embarcadero. Officials say the Muni trains were damaged in the crash. 

A passenger who was on board one of the involved trains said the impact of the crash knocked passengers over out of their seats.

"The train was getting ready to pull off slowly and all of a sudden we got a big jolt like somebody ran into the back of the train. It knocked some people off their seat, but I caught the bar. It didn't knock me off my seat," said rider Spencer Haynes. 

If you look at the video of the aftermath of the crash, you can see the damage to the light rail vehicle that appears to have rear-ended the train in front. Both San Francisco Municipal Transportation Agency and SFPD are investigating this incident. 

They said it's too early to say what caused the crash, but SFMTA did say the light-rail vehicles are more or less computer controlled when they are underground, but once they emerge from the tunnels and travel on the street level, the operators take over, because it's a more dynamic environment with cross traffic and pedestrians. 

"We have signals that keep the trains separated, and then we have operator training about how to follow those signals on the surface. So we have multiple systems in place and the question for us is to figure out what happened here," said Tom Maguire, an SFMTA spokesperson.

Police said both Muni operators remained on scene and are cooperating with investigators. 

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This story is developing, KTVU will update it as more information is made available.