The 4 Lexington Avenue Express is a rapid transit service in the New York City Subway's A Division. Its route emblem, or "bullet", is colored green since it uses the IRT Lexington Avenue Line in Manhattan.
4 trains operate between Woodlawn in the Bronx and Utica Avenue in Crown Heights, Brooklyn via Jerome Avenue Local in the Bronx, Lexington Avenue Express in Manhattan, and Eastern Parkway Express in Brooklyn at all times except nights. During nights, they serve all stops except Hoyt Street and are extended to/from New Lots Avenue in East New York, Brooklyn via Livonia Avenue to replace the 3. Limited rush hour 4 trains also extend to and from New Lots Avenue for storage at the Livonia Avenue Yard.