The MTA says normal service was resuming on the E, F, M and R lines for the morning rush hour following last week's derailment.
The agency says all of the subway cars that derailed in a Queens tunnel on Friday were removed from the tracks over the weekend. The derailment injured 19 and stranded hundreds of riders.
A rail snapped and caused six cars of a Manhattan-bound F train to leave the tracks.
The rail that broke was manufactured in the U.S. in November and installed in March. The MTA says the other rails from that shipment will be tracked down and inspected.
The train's operator and conductor were tested for drugs and alcohol, but results were not immediately known. A rail snapped and caused six cars of a Manhattan-bound F train to leave the tracks on Friday. MTA officials are investigating why the rail broke just weeks after being installed.