By Jerold Chinn : sfbay -excerpt
Despite a computer glitch that led a Muni 3-Jackson trolley bus to crash into a parked vehicle late Monday morning, transit officials say the trolley buses are safe.
Initial reports said Monday’s crash, which occurred near Jackson and Scott streets, was caused by failing brakes. However, a memo obtained by The San Francisco Examiner states the incident was actually caused by a malfunctioning computer system on the bus that was unable to communicate with the brakes.
John Haley, director of transit for the San Francisco Municipal Transportation Agency, wrote in the memo to Mayor Ed Lee and the directors of the SFMTA board that when the operator applied the foot break, it should have sent a signal to the traction motor to decelerate, but it did not.
Haley continued to cite in the memo that when the operator activated the parking brake valve, it should have also activated the same traction motor to reduce power, but that did not happen either…
One Muni operator who spoke to the Examiner under anonymity said it’s not uncommon to lose steering and the ability to break while in restrictive mode. According to the operator, this has happened at least 10 times and is a “danger for you and your passengers.”
Other operators reiterated the same story, reported the Examiner. Brake failures are another problem operators said they experience on the trolley buses.
However, Rose said if a trolley bus has battery power, steering should continue to work. He countered that the bus does not lose the brakes in restrictive mode, which transit officials confirmed with SFMTA mechanics Friday morning.
The transit agency looked at recent incidents involving restrictive mode and found that none of them involved a collision or put passengers at risk, said Rose….(more)