Shuttle buses are replacing the subway along parts of the M, J, 7, 4 and 5 lines this weekend.
The 100-year-old Myrtle Viaduct, which takes M trains between Bushwick in the Queens, has been demolished and rebuilt. The Fresh Pond Bridge work at the terminal end of the line near Maspeth was done in September.
Transit officials say the project was done on-time and on budget.
During the two phases of the $163 million dollar project, a new 310-foot concrete structure on the Myrtle Viaduct between Myrtle Avenue and Central Avenue stations was constructed, 310 feet of newly constructed low vibration tracks to reduce noise for nearby properties were installed, along with 700 feet of new third rail.
Hundreds of feet of track ties and replacement of all local signal equipment and cables was also part of this project and others.
Work to upgrade the signal system along the 7 train has been going on for years and the MTA has moved the timeline again. Crews hope software and hardware will be operational b y the end of 2018.