A northbound A-train was pulling into the station when it hit debris on the tracks, "resulting in a wheel leaving the track."
"The matter is under investigation," Feinberg said in a statement. "The incident caused a loss of power to all four tracks."
A Fire Department spokesperson said three passengers suffered minor injuries in the derailment.
One person was taken to a hospital for evaluation and the other two declined treatment, according to FOX5.
The New York Police Department (NYPD) said the train derailed after someone threw debris from a construction project onto the tracks.
The New York Post reported that good Samaritans grabbed the man and held him until the police arrived.
“He was apprehended by the customers and he is now in custody,” one MTA worker told The Post.
The New York Daily News reported the 30-year-old suspect was "laughing" after tossing the items onto the tracks, causing the derailment.
Police later charged 30-year-old Demetrius Harvard with reckless endangerment, criminal mischief, assault, and criminal trespass, authorities said.
The MTA's chief safety officer, Pat Warren, told reporters during a brief news conference there were 135 people on the A train at the time of the incident.
"The heroic crew of that train were able to stop the train at the time of the incident," he said.
Warren said that officials so far ruled out malfunctioning equipment or crew error.
The derailment caused major delays for trains that use the 14th Street station along the Eighth Avenue line and throughout the system, including the A, C, D, E, and F trains.
Some 125 riders were safely evacuated from another train that was stuck in the tunnel near 34th Street when the power went out, according to transit officials.
The head of subways, Frank Jezycki, said there was "significant damage" to the train car and track components. The derailed car also struck several steel structural columns.
The Associated Press contributed to this report.