Turns out the bolt that brought a San Francisco cable car to a screeching halt on Wednesday, came from the cable car system. Muni officials confirmed the bolt had shaken loose from a screw plate on a switch near Washington and Powell streets. The bolt lodged inside the track causing car No. 25 to come to a sudden halt.
The morning accident injured seven people, including the cable car’s two operators. Muni said the operators were hospitalized and released. Muni described the injuries to the other passengers as minor.
Muni’s Director of Transit Operations, John Haley, said the bolts in the cable car line’s 41 switches are visually inspected daily. But following the accident he said the agency planned to change its procedures.
“What we will do now, in addition to visually checking them,” said Haley, “at least once a week we will tighten up all the bolts.”
Haley said the underground cables which propel the cars are wrapped in sensors that trigger an alarm back at the cable car barn when an obstruction is detected on the tracks. Haley said the alarms are normally triggered two or three times a day, prompting Muni workers to shut down the lines. But on Wednesday, he said the alarm failed to sound.
“The incident yesterday wasn’t picked up by the sensors,” said Haley, “because the bolt was jammed above where the sensors are.”
In addition to Muni’s investigation into the incident, California’s Public Utilities Commission sent inspectors to examine the tracks. A spokesman for the agency, which has jurisdiction over all public rail transit, said no decision had been made on whether the P.U.C. would compile its own report.
“If a report is created and finalized, it goes to the rail transit/guideway agency,” wrote CPUC spokesman Christopher Chow, “including any necessary corrective action plan requirements or any other actions that might be deemed appropriate by the results of the investigation.”
Cable car accidents have cost San Francisco millions of dollars in legal settlements over the years. In 1995, the city paid $4 million to a Canadian tourist who had part of his leg amputated after a cable car he was riding in was struck by an empty cable car that had broken loose and coasted down a hill.
Muni said car No. 25 which involved in Wednesday’s incident had been taken out of service temporarily for repairs. Despite the accident, many passengers said they would continue to ride the city’s rolling wooden ambassadors.
“I’ve always thought for as many cable car rides as I see every day and long as they’ve been doing it,” said rider Michele Brown, “ it doesn’t seem like it happens very often.”