I'm writing a book, and I've struck out with regard to finding information. I'm curious as to the route a train would have taken from New York City to Georgia in the early 1940s.
Would it have left from Penn Station? Grand Central? What bridge/tunnel would have crossed to get into New Jersey?
The layout of tracks was more-or-less the same in 1940 as it is today. Funnily enough, the train Amtrak runs on this route, the Crescent (which continues on to New Orleans) ran in the 1940s too, run by the Southern Railway. That wasn't the only train running from NYC to Atlanta at the time, but they all did have the same route out of New York.
The reason for that was, as today, that there was only one railroad station in New York that was able to run trains from the city itself south--all other railroads in New Jersey had to end in Hoboken or Jersey City. Grand Central only can run trains north, so the only option was Penn Station, which also meant using the Pennsylvania Railroad's route from Penn Station, through the North River Tunnels, to Newark, and down the line to Washington DC. That's because the North River Tunnels from NJ to Penn Station is the only rail crossing of the Hudson River until you go upstate. This is the same route Amtrak uses today.
So the train would've left Penn Station, gone through the North River Tunnels, to Newark, and then south from there, just as Amtrak does today.
For more information, I'd suggest you check out railroad.net's forums--they have lots of people with more detailed historical route information, historical timetables, etc.