Muni trains entering West Portal Station have slowed over the last few days due to an equipment issue with the subway’s automatic train control system.
The San Francisco Municipal Transportation Agency posted about the delays on Wednesday on its website explaining that the control system was damaged during work being performed last weekend inside the Twin Peaks Tunnel by the project contractor, the SFMTA wrote.
Work was being performed during the late-night weekend closure of the tunnel so the contractor, Shimmick Construction, can “perform routine tasks” as required in the contract with the SFMTA. A final late-night weekend shutdown will occur again this weekend.
Shimmick Construction came under scrutiny in August when worker Patrick Ricketts died after a steel beam fell on him during Twin Peaks construction work. Prior alleged workplace violations were uncovered — including a worker fatality and a history of fines from regulators — that had gone unreported by the company during the bidding process.
Crews completed the majority of the work inside the tunnel late last month.
While the contractor was working inside the tunnel last weekend, the SFMTA wrote that crews used equipment that damaged parts of the automatic train control system. The system controls the train inside the subway.
Last Saturday, trains experienced problems with the control system when trains began to stop randomly before entering the station.
In order to get trains moving, operators have to reduce the speed of trains through West Portal and Forest Hill stations. Trains can move at normal speeds once at Forest Hill Station, which has slowed subway service.
The transit agency said it had made numerous attempts to fix the issue, including replacing the parts of the control system and is now working with the manufacturer, Thales Group.
Officials said if the delays persist, the transit agency will have staff positioned at West Portal Station to make mechanical and electrical adjustments to keep trains moving through the subway.
The SFMTA hopes to have a fix by this week.