Your day trip starts at the Amtrak station in Philadelphia, where you'll board your train to Washington D.C., arriving at Union Station in the late morning. If you're hungry, you might want to grab a snack at the station upon arrival, or just head straight to the Hard Rock Cafe for your included 2-course lunch with priority seating.
If you choose to do lunch later, start your hop-on hop-off tour by boarding the double-decker bus waiting outside the train station. This tour provides convenient transportation around the city, allowing you to hop off at the sites that interest you and then get back on the bus when you're ready to move on. Perhaps visit the National Archives, home to the Declaration of Independence, or check out one of the museums of the Smithsonian Institute, such as the National Museum of Natural History or the National Air and Space Museum.
Other attractions you might want to visit include the International Spy Museum, Madame Tussauds, the United States Holocaust Memorial Museum, Arlington National Cemetery, the Vietnam Veterans Memorial, or Ford's Theatre, where President Abraham Lincoln was shot.
In the late afternoon, return to Union Station to walk around a bit before boarding the Amtrak train for the return ride to Philadelphia, where your tour ends.