Photo: Chelsea Guglielmino/Getty Images What if the Underground Railroad’s most famous conductor dropped an album? Harriet Tubman: Live in Concert , out March 25, is a 240-page answer to a question Bob the Drag Queen can’t stop thinking about; the debut author, who uses he/him and she/her pronouns, is already working on a stage adaptation. Longtime fans have been hearing about the Drag Race winner and Traitor ’s self-described obsession with Harriet Tubman for years. “I’ve listened to multiple