A loss of power at the 81st subway station at the tail end of the morning rush on Friday was restored in the late morning.
Service, as a result, was also back on the A, B, C and D lines.
Straphangers are warned to expect residual delays.
Service was suspended on those lines in both directions between 59th and 125th streets in Manhattan.
The MTA recommended commuters use the 1, 2, 3, 7, R and Q trains or the M10 bus along Central Park West/ 8Ave. as an alternate.MTA.info