Anybody able to guess a route ?

Hi folks !
When I was about 5 years old around 1956, my mom took me to visit my uncle, a U.S. Army Serviceman at Fort Bragg, North Carolina. Leaving from Boston, I'm guessing that we took one of New Haven's or New York Central's runs out of South Station to NYC or D.C. From that point on, I have very spotty memories. I know that we got to D.C., saw the Lincoln Memorial in daylight, and I remember the large terminal there. I also recall a very long night train (long as in numbers of cars) out of D.C. in which we had a sleeping berth.
Could anybody knowledgeable with various schedules of the day hazard a guess as to what railroads we travelled on between Boston and Fort Bragg ? Would the actual train be too hard to figure out as well, or where there many possibilities of different routings on a trip like this in 1956 ? Any help would be appreciated as being a buff, I would like to mentally know that I travelled on a road that 52 years later I don't really recall.
(P.S. We should have returned by train as well, as on the way home late at night in the middle of a snowstorm in New Jersey, in a car driven by an in-law, we got in a bad accident and were lucky that we weren't all killed. Car was crushed after it was run over by a semi tractor-trailer. We were all expelled into the snowy street, which actually saved us.)
Thanks.

Fort Bragg is located close to Fayetteville, N. C, which was always primarily a feifdom of the Atlantic Coast Line. Both ACL and its primary competitor, the Seaboard (Air Line), routed their passenger services to the north via Richmond and the Richmod, Fredericksburg and Potomac. Combining two schedules on the Washington-Richmond portion of the trip would account for the long train.

New Haven and the Pennsylvania enjoyed a similar dominance on Boston-Washington traffic via the Hell Gate Bridge. The alternatives, a routing Boston-Albany-New York-Washington using Boston and Albany/New York Central and/or Baltimore and Ohio NewYork-Washington, are possible in theory, but highly unlikely. NYC used Grand Central Terminal while Pennsy used its namesake (New Haven could serve both), and while B&O used Penn Station for it's "Royal Blue" New York-Washington service for a time, it would have departed from Jersey City by 1956.

Thanks 2nd trick op. With D.C. as the start of either an Atlantic Coast Line or Seaboard company trip heading south, would one have more dominance in D.C. as opposed to the other ? (Better fare, schedule, ticket office, etc.) I'm guessing that the tickets were probably bought in D.C. I know that it was a night train and that it probably left D.C sometime in the evening.

As 2nd trick op implies, it's almost certain that you took a joint New Haven-PRR through train between Boston and Washington. From Washington to Fayetteville you were on the ACL, but I'm not sure exactly which train it would have been. The through ACL trains stopping at Fayetteville originated at New York on the PRR, but evidently you stopped over in Washington and then got an ACL night train. If so, in 1956, ACL #75, the "Havana Special", carried a Washington-Orlando sleeper that you'd occupy in Washington at 9:30 PM, and would have arrived in Fayetteville about 9:20 AM. Otherwise, I don't see any sleeper service that would match your description, but I may have missed something.

Thanks BaltOhio. That would make perfect sense, as I have one memory only on that train. That is looking out the window in our compartment and seeing a long stretch of cars on a left hand curve at night. Even back then, I was a train buff, so for me not to recall anything else about the trip tells me one thing- I was asleep. The timing on the 9:30 - 9:20 "Havana" would fit right into the scheme of things. Any idea what the consists would be on the Havana in '56- heavyweight or streamlined cars, ACL EMD E units with the purple scheme ? (Too late for steam ?) I'll ask this on the ACL forum also.