A bolt in the tracks appears to be the cause of a San Francisco Municipal Railway cable car accident Wednesday morning that hospitalized seven people on board, a Muni spokesman said.

A bolt was found stuck in the trackway, which caused the inbound Powell-Hyde cable car to stop suddenly at Powell and Washington streets around 10:15 a.m.

Five passengers and two cable car operators were transported to the hospital with minor injuries. Three other passengers were treated at the scene for minor injuries, as well, according to police.

Police said one of the passengers fell out of the cable car when it suddenly stopped.

Bus shuttles are in place for riders on the Powell-Mason and Powell-Hyde cable car lines, Rose said.

Regular cable car service was expected to resume around 1:30 p.m., he said.

Rose said investigators were looking into where the bolt was from and how it got into the track.