Maintenance work will cancel overnight B/D/F/M service this week

Overnight maintenance work will shut down a large chunk of the Sixth Ave. subway line nightly in Manhattan this week, forcing thousands of straphangers to find another way to get around.

Starting Monday, service will be canceled between 10 p.m. and 5 a.m. on the B/D/F/M lines between 59th Street-Columbus Circle and West Fourth Street. Regular service will resume Friday.

The MTA says as many as 37,500 riders will be affected each night by the shutdown, and should add about 20 extra minutes to their commute.

The agency says the maintenance program, called "Fastrack," lets workers do their jobs more efficiently because they don't have to pause work and get off the track when a train passes by. The next shutdown will take place in September on the No. 4/5/6 lines.