Shuttle buses briefly replaced service along a section of the MBTA's Red Line on Thursday morning.
The MBTA said just before 6:30 a.m. that shuttles would be replacing service between Harvard and Park Street because of a power problem at Charles/MGH.
Riders were told to expect delays as shuttles were being dispatched.
Around 15 minutes later, the MBTA said that shuttles were being phased out and that service was resuming with delays.
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