By Chris Lisinski, State House News Service
STATE HOUSE, BOSTON, Feb. 21, 2014 (State House News Service) – A “failed joint” in a feeder cable caused last week’s power outage that upended the morning commute on three of the MBTA’s four subway lines, officials said Wednesday, somewhat contradicting the T’s earlier suggestion that its own infrastructure did not appear to be the problem.
Six days after the incident that prompted major delays on the Blue, Green and Orange Lines, the MBTA said its power department determined that a joint in the roughly seven-mile-long feeder cable was to blame.
“The MBTA is working diligently to address a power infrastructure issue that caused a recent disruption,” T spokesperson Joe Pesaturo said in a statement. “Teams have pinpointed the cause — a failed joint in a feeder cable located underground, only accessible by manhole — and are replacing the damaged cable section. By leveraging backup systems utilizing energy from other parts of the power grid, service has continued safely through alternate feeder cables in the interim.”
Pesaturo said MBTA engineers will test the repaired cable before it returns to service, adding that the T “remain(s) committed to maintaining and upgrading critical system infrastructure to provide reliable public transit services to our riders and thank them for their patience.”
Last week, while investigators were still working to determine the cause of the feeder cable failure, MBTA General Manager Phil Eng said the incident initially appeared to occur “outside of our infrastructure.” But Pesaturo confirmed Wednesday that the issue “was not related to any external factors.”
“Teams continue working to uncover the specific internal factors within this cable section that led it to fail,” he said.
The cable’s failure tripped circuit breakers as a failsafe to prevent a large issue from erupting, Eng said last week, and it took workers a few hours to restore power. Six other feeder cables remain operational, providing enough electricity to keep trains moving.