It's been nearly 30 years since Stephen Flaherty and Lynn Ahrens wrote the music and lyrics for the musical “Ragtime,” an American epic tracking the intertwining lives of three families in New York at the turn of the 20th century. Staged at Lincoln Center’s Vivian Beaumont Theater, the musical is in its third run on Broadway — and earned 11 Tony nominations, including for best revival. It's resonating the most with audiences this time, they said. “Three is the charm,” Ahrens said. “When we originally did it on Broadway, which was 1998, I think a lot of people, if not...