When the construction of Phase 3 is completed, a new T service will operate from Harlem–125th Street to Houston Street. After Phase 4 opens, T service will run the full length of the line, from Harlem–125th Street to Hanover Square. T service is planned to operate at a frequency of 14 trains per hour during rush hours, with the combined frequency north of 72nd Street with Q service being 28 trains per hour. With the opening of Phase 3, the frequency of Q service is planned to be reduced from 19 to 14 trains per hour.