The portion of the L train that connects Manhattan and Brooklyn will be shut down entirely for repairs.
Riders will have to find another way to get around starting January 2019.
After several public meetings, transit officials decided to close the L train's East River tunnel for a year and a half to fix damage caused by Hurricane Sandy.
The tube carries tens of thousands of riders every day between the two boroughs.
Service will be suspended between 14th Street-Eighth Avenue in Chelsea and Bedford Avenue in Williamsburg.
The other option would have stretched the repair work out over a three-year period in order to allow limited service.
Transit officials say the one-and-a-half year shutdown is the most sensible choice.
"During the process, it was interesting to me, a public consensus actually formed, and it’s the one that we have, which is to do an 18-month full tunnel closure," said Ronnie Hakim, president of New York City Transit. "Off the comments that we received directly, 77 percent were in favor of the full tunnel closure."
The MTA says it will try to help relieve crowding by boosting train service on nearby lines like the G, J and M trains.