Train enthusiasts open their yards to share train layouts featuring cities, towns and landscaped gardens, as well as holiday lights and decorations. Presented by Arizona Big Train Club, the annual Christmas open-house tours take place at 14 homes and a medical center. Sa-Su, 5:30-8:30 p.m. Greater Phoenix area; map available at azbigtrains.org. Donations appreciated to support maintenance of railroads at Ryan House and Cardon Children’s Medical Center at Banner Health.