Chart Preview tease

YOUR RADIO CHART PREVIEW: Epic's Meghan Trainor retains the #1 spot at Top 40 radio next week, but Big Machine's Taylor Swift has another Greatest Gainer week and is poised to make a move on the top spot soon. Grand Hustle/Def Jam's Iggy Azalea jumps to #3, and two songs you'll recall from Shazam's picks to click in the fall, "Habits" by Island's Tove Lo and "Waves" by Ultra/RCA's Mr. Probz, are on the cusp of big moves. At Rhythm, Def Jam's Jeremih is still on top but has T.I. f/Iggy (Grand Hustle/Columbia) and Iggy f/Rita Ora dogging his heels. Republic's Milky Chance (another Shazam pick) rules on at Alternative as Epic's KONGOS and Nonesuch/Warner Bros.' The Black Keys eye the Top 10. See our preview of all the action on three key Mediabase charts here; it's like traveling into the future for a really specific reason. (9/26p)