The 3 Seventh Avenue Express[3] is a rapid transit service in the A Division of the New York City Subway.

Its route emblem, or "bullet", is colored red since it uses the IRT Broadway–Seventh Avenue Line through most of Manhattan.

Overnight service short turns at 34th Street–Penn Station in Midtown Manhattan and does not operate to or from New Lots Avenue.

The 3 train formerly ran to City Hall or South Ferry in Manhattan, and was later rerouted to Flatbush Avenue–Brooklyn College in Brooklyn.

On February 6, 1959, all trains except late nights made express stops in Manhattan as part of the "West Side Improvement" and ran to Flatbush Avenue.

[14] In January 1991, a reduction of service along the Eastern Parkway corridor to remove excess capacity was proposed.

Weekend daytime 3 service would be rerouted to originate and terminate at South Ferry in Manhattan instead of New Lots Avenue in Brooklyn.

Also on this date, 3 trains began to permanently use consists of 10-car trains as a result of equipment sharing between Livonia Yard (the maintenance facility in Brooklyn where subway cars assigned to the 3 are based from) and 240th Street Yard (the maintenance facility in the Bronx where subway cars assigned to the 1 are based from).

[23][24] On November 17, 2019, New York City Transit made adjustments to weekday evening 3, 4, and 5 service in order to accommodate planned subway work.

This change, which was approved by the MTA Board on June 27, 2019, was expected to save the agency $900,000 annually.

[27] One month later, some weekday early morning and late evening trips were rerouted to and from 137th Street–City College as a result of accessibility improvements taking place at 148th Street.