Thanks to "Glee," we've gotten used to songs introduced on a TV show immediately charging up (and then down) the sales charts. However, the success of the songs from ABC's new drama "Nashville" seems different: The songs stick around.

Maybe it's because "Nashville" -- which follows the travails of country singers, including fading star Rayna Jaymes (Connie Britton) and up-and-comer Juliette Barnes (Hayden Panettiere) -- keeps the songs around for more than one episode. Maybe it's because the music is being helmed by well-respected, Grammy-beloved producer T-Bone Burnett, who's been attracting first-rate talent for the show's music, including alt-country queen Lucinda Williams and indie-rocker Dan Auerbach of the Black Keys.

The first song launched from the show is a cover of The Civil Wars' "If I Didn't Know Better," done by Sam Palladio and Clare Bowen, who portray songwriting newcomers Gunnar Scott and Scarlett O'Connor on the show. The song hit the Top 5 on the iTunes country chart when it was released, and now, a month after it aired on the show, it is still climbing on the country charts. The show has spawned five hits on Billboard's country singles charts, which all look like they have some staying power.