The MTA's FASTRACK maintenance program comes to the N, Q, R and W lines this week.
Repair work started Monday night and takes place for the following three nights.
It is scheduled to run from 9:30 p.m. until 5 a.m. each evening and wraps up Friday morning.
N trains are slated to run only between Ditmars Boulevard and Queensboro Plaza in Queens and between Stillwell Avenue and Court Street in Brooklyn.
The Q will be rerouted to the D and F lines in Manhattan and Brooklyn.
Service on the R and W lines ends early in Manhattan and Queens each night.
For travel alternatives, visit the MTA's website.