T riders' morning commute into Boston was snarled Tuesday morning when a power issue impacted the signal system on multiple lines, the MBTA said, causing widespread but mostly brief interruptions to service in and around the city.
There were residual delays hours after the issue, which an MBTA representative said was due to a transformer failure that caused a power surge, affecting signals on every rapid transit line and some stations, including their elevators. The agency stopped all trains "out of an abundance of caution," and signals returned to service within about half an hour.
"The root cause of the transformer failure is under investigation," MBTA spokesman Joe Pesaturo said in a statement.
The issue took place during a winter storm that was expected to drop several inches of snow across the Boston area by the end of the day Tuesday and slowed the morning commute on the area's roads.
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Massachusetts Transportation Secretary and CEO Gina Fiandaca said the issue was at the MBTA's South Boston Power Facility, but it wasn't immediately clear if it was related to the weather.
"Signals were out and power impacts were experienced on all lines with delays," she said, noting that emergency officials were able to respond quickly and the system was using backup power as of the late morning.
The power surge hit about 7:30 a.m., and the agency said soon afterward that it was working on a power issue that was impacting the signal system on multiple lines. The MBTA said it asked trains to stand by at stations.
Many people on Twitter replied to the MBTA, saying that their trains weren't moving across a variety of stations.
Around 20 minutes later, the MBTA said that the power had been restored, but residual delays would linger as service resumed.
Power was restored after about 10 minutes, and signal systems returned about 25 to 30 minutes after that, Pesaturo said. Alerts went out over phones, social media, in stations and on trains.
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Issues continued at Copley Station, where trains were being held in both directions as they traveled through the area as of around 9:30 a.m.
Passengers on a Green Line train told NBC10 Boston that they were stuck for about 10 to 15 minutes right before Copley Station.
"The train stopped all of a sudden, it seemed like we were at a stop, but all the lights were off, so we couldn't really say for sure," Jack Sheehy said. "All the lights were off. The train just like stopped making noise and we just didn't really know what was going on."
Residual delays on the Green Line at Copley Station were over by about 10:45 a.m., according to the T.