The Long Island Rail Road was experiencing a normal rush-hour Friday morning, according to the MTA's website, which indicated good service on all branches.
This in the wake of disruption Thursday when a cut signal cable led to a shutdown of two tunnels during the afternoon commute.
The cable operated signals in two of the four East River tunnels, and it was inadvertently severed by a contractor excavating in Queens as part of the East Side Access, Long Island Rail Road officials said Thursday.
Donovan said an investigation is underway on how the contractor, Tutor Perini Corp., damaged the cable.
Workers with heavy equipment damaged the cable during construction to realign rail tracks and install more switches near the LIRR Sunnyside yard, Donovan said. The California-based company was awarded the $261-million contract for the Queens work in 2008 to help link LIRR to Grand Central Terminal.
"They were excavating to demolish manholes," Donovan said. "They dug in the wrong area."
A spokesman for Tutor Perini on Thursday referred questions to the Metropolitan Transportation Authority, which operates the LIRR.
The signals were lost at about 3:10 p.m. and became a bigger problem during the afternoon rush, when three of the four tunnels are normally reserved for eastbound trains. At least 45 trains were delayed Thursday night and at least 13 canceled out of 128 peak-hour trains, the LIRR said.
Crews were expected to work overnight to avoid morning delays.