State safety inspectorates said they had launched an investigation into Friday's recent breakdowns with Muni's new fleet, which focused on the collapse of the last week of the coupler system and the accident involving an elderly woman putting her finger in a door and on the door was pushed tracks as the train left.
The public utilities commission (Public Utilities Commission), which has been mandated with the certification of public transport systems, has already reviewed a video of the recent accident at Embarcadero station on Friday and will next week check the coupling system of the new Muni cars , Last week, Muni discovered two separate failures of so-called shear bolts, the steel rods, which both help to couple the trains together, and were designed to offset the shock of the collision in interconnected cars.
"We know and we are investigating what happened and why," said Constance Gordon, Commission spokeswoman. "We look at both the door problems and the problem of coupling pins on the new SFMTA vehicles."
The accident involving the door was recorded in Muni's own video, which was first investigated by the SF Examiner. It shows an elderly Asian woman approaching the train and trying to open the door with her hand.
A few moments after the woman was caught, the video shows a stationmaster who beckons her to get off the train.
The stationmaster then warns others to leave the train and turn their backs to the woman who had to be hospitalized with serious injuries.
The acting transit director for Muni, Julie Kirschbaum, said on Thursday, NBC Bay Area, that she had a "deep concern" that the operator apparently did not discover the woman and kept the train until she could be released.
"We take this as a deep concern," she said.
The incident is one of two documented cases in which people have trapped fingers in Muni doors. The other incident occurred in December.
Kirschbaum emphasized that although the doors of the new fleet were considered safe by the state regulators, all trains should be retrofitted with additional sensors to make them safer.
Currently, most of the new vehicles are the case Cars have sensors only on the right, while the system's old cars have sensors on the left side of the door.
The new cars from Siemens also have no side mirrors, so the operator needs this rely on video cameras to ensure that no one gets caught in the door.
Kirschbaum said the agency continues to investigate why two shear pins have broken on the new trains. The pins are described as fail-safe devices to spread the force of accidents when two or more cars are connected together.
The discovery of the first failure occurred on Thursday afternoon in a two-wheeled train on the N-Judah Line – after It had ended its daily service.
The driver reportedly heard a crackling noise and the train's computer diagnostics indicated that a problem had been detected.
This resulted in inspections in which a second broken pin was uncovered on a vehicle uncoupled in a muni yard.
All replacement needles were sent out for metallurgical and chemical analysis, she added, adding that it was still not clear what caused the mistakes. Meanwhile, the new cars are driven only as single carriage trains on the N-Judah line.
The cause of the failures is puzzling, she says.
"We have a system that has a lot of tight corners and difficult terrain," said Kirschbaum, "but the vehicle was designed specifically for our system, so we need to understand that better and then repair and continue."