WASHINGTON — The Washington Area Metro Transit Authority showcased their new 8000-series train and zero-emissions bus at the Fleet of the Future Expo on the National Mall. Attendees can walk through and explore the train and bus model, which highlight new features the fleet will bring to the Washington Metro. The 8000-series trains are the second subway system in the country to have open passageways between train cars, and developer Hitachi Rail said the cars will finish construction by late 2025. The Expo ends April 3.