The SAS could get a second line to Queens, given that current plans call for a spur to the 63rd Street line toward 21st Street - Queensbridge. From there the line can continue as an elevated structure above the LIRR between Sunnyside Yards and the Forest Hills - 71st Avenue station where it connects to the local tracks along the Queens Boulevard corridor. This new line would be a turquoise supplementing the south of 55th Street, operating local east of that station to 179th Street, operating express to 21st Street via the 61st Street - Woodside station, and then making all stops to Hanover Square after Lexington Avenue - 63rd Street station. It would operate at all times except late nights.
To accommodate this new service, the would run express east of 71st Avenue at all times except late nights when it operates local in Queens. service along this segment toward 179th Street would remain unchanged.
However, I also have to admit that such a plan would first require that Jamaica Yard be expanded as overcrowding has forced the storage of trains on the express tracks east of 71st Avenue during late nights and weekends.