For starters, lets take a page out the IND book with the Fulton Street Line and make the Jamaica Line, a 4 track cut and cover line under Broadway and Jamaica Ave with express stops at Bedford Ave, Marcy Ave, Myrtle Ave, Broadway Junction, eliminate the S-curve between Crescent St and Cypress Hills and combine those two stations as Cypress Hills-Crescent St and make it an express stop, Make Woodhaven Blvd and 121 St express stops and extending line past the Jamaica Center to Laurelton