The 7 train is the main numbered service of New York City’s Flushing Line. It runs between 34th Street–Hudson Yards in Manhattan and Flushing–Main Street in Queens, crossing the East River through the Steinway Tunnel.
The service is often associated with Queens because much of its route follows Roosevelt Avenue and connects major communities including Long Island City, Sunnyside, Woodside, Corona, and Flushing. The 7 also serves the Mets–Willets Point station, which provides access to Citi Field and the USTA Billie Jean King National Tennis Center.
Most 7 trains operate locally, while the peak-direction 7 Express skips some stops in Queens. That express designation is a service pattern, not a separate numbered route. The line opened in stages during the early twentieth century and reached Flushing in 1928.