What is the song playing in 500 Days of Summer when Summer and Tom are on the train BACK from the wedding?

Not Sweet Disposition by Temper Trap. That was the song playing on the way to the wedding, but the one on the way back, after they were dancing at the wedding and Summer invites Tom over for a party. They're sitting together on the train and Summer slumps onto his shoulder. The song has a ton of strings, and I don't think there are any lyrics, so I don't know how to look it up! Please help!!!