Train spotting at BWI Thurgood Marshall rail station. Many varieties operating along the Northeast corridor ranging from the AEM7s to it's successors the ACS Sprinters. Including one retired AEM7 given to MARC as a handmedown. Three of MARC's Bombardier Multilevel carriages on the express tripper. Two Acela Express trains heading to Boston, Massachusetts. This was during evening peakhour, so plenty of airplanes were takingoff and taxiing into Runway 15.