Edit: On the discharge north of ALX bit, Charlie and I were talking, and at one point Amtrak was very flexible because once you dropped the LD trains, you might well be down to only a few of what we'd call Regionals south of PHL (PHL-NYP had extra coverage due to the presence of the Clockers). The change is likely due to the sheer, massive number of both Regionals and Acelas now operating there...though I'll refer to the point I've made about selling a carefully controlled number of seats and whatnot NYP-WAS (not unlike the CHI/MSP or CHI-STL sales on the Eagle).
Just as a data point to augment this discussion, in 1969 there were 12 to 13 daily trains other than LDs between Philly and DC. Of these 4 were through trains from Boston, including the overnight
Federal (except Saturday) and two were
Congressionals and one
Keystone. The rest, except one no name number 108, had names. The Boston trains were the
Senator, the
Patriot, the
Colonial and the
Federal. This in comparison to 21
Regionals on weekdays today of which variously 9 run through to Boston and a couple to Springfield on weekdays (including the
Vermonter). The
Acelas are in addition to all those. So effectively service has almost tripled in number of trains and possibly a little more than doubled in terms of cars since 1969.
On the LD front towards Florida there were a total of 6 trains south of Philly compared to 3 today (though RF&P claims there were only 5!) - 2 Miami/St. Pete trains viz. the
Silver Star and the
Champion. One Miami train - the
Silver Meteor and one Tampa train - the
Gulf Coast Special. Additionally, the moral equivalent of today's
Palmetto - the
Everglades ran on a significantly longer schedule than today's
Palmetto does between New York and Savannah. And there was the
Palmland which ran to Columbia SC. The Silver Meteor and the Champion were R/D between New York and Washington DC, and the four deep Florida trains had higher fares than the corridor trains.
On the
Southern there were 4 trains compared to 1 today though one could argue that the Lynchburg train is a truncated
Pelican - the
Crescent/Southerner (New Orleans via Birmingham southbound, via Montgomery northbound), the
Birmingham Special (Birmingham via Roanoke, Chattanooga), the
Pelican (Bristol VA, via Roanoke), and the
Peachtree (New Orleans southbound via Montgomery and the
Southerner (New Orleans northbound via Birmingham). BTW looks like the railways specialized in trying to confuse their customers and perhaps even themselves.