Cutting the sleepers out in Atlanta would require that they be maintained and stored there and switching be done to add them on. Not an easy thing at Brookwood. Amtrak gets little mileage out of that because they are not reused but just dropped and left.
Given that they are going to make the effort to do switching, better might be to run a split train - NYC to NOL and NYC to FLA via ATL and have the sleepers go to Florida. Then there will be an economic gain as they can get revenue.
In either case, it will probably take a new Atlanta station to do this.
They're not "dropped and left"; they're turned around and sent our that evening. Remember, there are four Crescent consists...in general, you've got two on each side of Atlanta at any given time. Let's say that you've got equipment sets A, B, C, and D. Currently, A leaves NYP on day 1, arrives in ATL on the morning of day 2, arrives in NOL late on day 2, leaves NOL on day 3, arrives back in ATL on the evening of day 3, and arrives in NYP again on day 4. B does this on days 2-5, C on days 3-6, and D on days 4-7.
What would happen is that B would drop its sleepers on the morning of day 3 and A would pick them up that evening heading back north. C would drop its sleepers and B would pick them up. D would drop its sleepers and C would pick them up. A would drop its sleepers and D would pick them up...and so on. The cars would be in ATL for about 12 hours, not 2-3 days.
On new services: I think Amtrak is going to settle on a service option in the PIP, but it'll take a few years to make happen. As it is, the RVR-Norfolk service was
announced, but it has about a two-year implementation period on the heels of a slab of EISes (which do make for an interesting read in some parts, though I must confess that the actual "environmental" parts bore me to death). These things tend to take
forever to make happen because of all of the agreements which need to happen to make the services actually come about. Thus, even if Amtrak announced tomorrow that it was running a train ATL-SAV, you probably wouldn't see it until 2014 (late 2013 if a bunch of GA politicians were twisting arms with the RRs and were bound and determined to make it happen in a hurry). An extra train on an existing route is a bit easier.
And on running the Crescent ATL-SAV...I'm wondering what that timetable would look like, at least as far as how long it would take to get to SAV. Depending on the time, you might end up with a
bad set of Florida times (I'm thinking early, early morning for Orlando) unless you hold the train in ATL for a few hours.