This episode's headline: Train Crash Probe; Under the Influence?; House of Cards; Phelps Dodge Plant Closing. The guests include In Washington: JOSEPH NALL, National Transportation Safety Board; Dr. ROBERT DuPONT, Psychiatrist; JOAN CLAYBROOK, Consumer Advocate; BOB CARLILE, American Bankers Association; In Boston: Dr. DAVID GREENBLATT, New England Medical Center; REPORTS FROM NEWSHOUR CORRESPONDENTS: ROD STEVEN (Visnews); SPENCER MICHAELS (KQED); PEGGY GIDDINS (KUAT-TV), in Douglas, Arizona. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor