A 1 p.m. Acela train to DC from Penn Station yesterday was apparently the “Homeland” express to the White House Correspondents’ Dinner. Spies said Claire Danes (who plays CIA agent Carrie Mathison) and Navid Negahban (a k a baddie Abu Nazir) were riding on the same train, heading to tonight’s event. A spy said Danes was with her husband, Hugh Dancy, and their newborn baby, Cyrus, and she made sure the family was seated in a “quiet car.” We hear the actress is sitting at a CBS table at the gala. Others heading from New York to the dinner emceed by Conan O’Brien include Barbra Streisand, who already accepted an award from Bill Clinton this week and is a guest of Mayor Bloomberg.