The 7 train is identified by the purple route color on New York City Subway maps.
The 7 service runs along the IRT Flushing Line between 34th Street–Hudson Yards in Manhattan and Flushing–Main Street in Queens. Express service is shown with a diamond symbol, while local service uses a circular route marker. Both versions use the same purple family associated with the Flushing Line.
The color system is based primarily on the Manhattan trunk line or corridor used by a service, not on the train’s entire geographic route. That is why several services can share a color, while a single line can have local and express variants.
The 7 line is especially associated with Queens, Citi Field, and the former international-express nickname. Its western extension to 34th Street–Hudson Yards opened in 2015, bringing subway service to the far west side of Midtown.