This weekend — late evening Friday, October 6 through early Monday morning, October 9 — 4 trains will not be serving Brooklyn in either direction. This means there will be no service at the 4/5 platforms at Borough Hall, as 5 trains do not serve Brooklyn on weekends. 2 and 3 trains should be running normally (except that 2 trains will be running on a reduced schedule during and, for those going to or from stations within Brooklyn, 2 and 3 trains will be serving all 4 train stops between Borough Hall and Franklin Avenue-Medgar Evers College, and 3 trains will serve all stops between Franklin Avenue and New Lots Avenue. For those traveling to or from JFK, A train servce between here and JFK will be interrupted in both directions. You will need to use the J train station at Sutphin Boulevard-Archer Avenue-JFK and transfer between the A and the J at Broadway Junction.
The following work week — Monday morning, October 9 through Friday evening, October 13 — late nights Monday to Tuesday through Thursday to Friday there will be no Brooklyn bound service at Court Street or at the N/R platforms at Jay Street-MetroTech, as Brooklyn bound N trains will be re-routed to the Q line between Canal Street in Manhattan ad DeKalb Avenue in Brooklyn, and R trains will not be running in either direction. These same late nights there will be no Manhattan bound service at High Street, as A trains will be re-routed to the F line between Jay Street-MetroTech in Brooklyn and Canal street in Manhattan, and C trains will not be running in either direction late at night. This means there will be extra Manhattan bound service at York Street in DUMBO. On these same late nights, for those traveling to or from JFK, it will be necessary to transfer between the A nd J at Broadway JUnction and use the Sutphin Boulevard-Archer Avenue-JFK J train station.
Always check MTA Info for last minute changes in planned service or unplanned service changes that may affect local service or service on other parts of your trip, or for planned service changes that affect stations to or from which you may be traveling. You can also get real time service alerts: register here.