Yes, you can take an Amtrak train from Washington, D.C. to San Diego. However, there is no direct route; you'll need to make at least one transfer, typically in Chicago and possibly again in Los Angeles. The journey can take over 70 hours, so be prepared for a lengthy trip. It's advisable to check the Amtrak schedule and book tickets in advance for the best options.
"Can you switch to an earlier Amtrak train?"
You could try going by Amtrak. San Francisco has about 5 to 7 (somewhere around there) Amtrak stations, and San Diego has one too. I'm not sure about the route since there's more than enough stations in San Francisco, though.
Amtrak is not a good option since you will have to go up to Washington, DC and then catch another train to come back down to New Orleans.
It is about an hour north....best way to get there is either take Interstate 5 north by car to Oceanside, or take the Amtrak from the train station near the airport to the base. There is also a San Diego commuter train called the coaster, but I don't know if it reaches Oceanside easily...
To travel by train from Savannah to Charleston, you can take an Amtrak train from the Savannah Amtrak station to the Charleston Amtrak station. The journey typically takes around 2-3 hours, and you can check the schedule and purchase tickets on the Amtrak website or at the station.
You will have to take Amtrak to either New Carollton, MD or Washington, DC.
Amtrak is the only train option.
To travel by train from Washington, DC to Charlottesville, you can take an Amtrak train from Union Station in DC to Charlottesville's Union Station. The journey takes about 2.5 to 3 hours, and tickets can be purchased online or at the station.
24 hours from Orlando to Philadelphia on the Amtrak train
Depends on the Amtrak train: Northeast Regional trains average about 4 hours (=/-) Acela Express trains average about 3 hours (=/-) (I checked the Amtrak Northeast Corridor timetable)
Amtrak is not an efficient way to travel between Atlanta and Miami. You have to take a train to Washington, DC and then change to the train to your destination. It takes about two days. The Greyhound bus takes about 16 hours.
The closest Amtrak station to Winchester is Martinsburg, WV. The Capitol Limited runs between Washington DC and Martinsburg.