The closest I come to that is 1938.
This would be the Pennsylania Railroad from NYC to Washington, then the Southern RR from washington to Lynchburg, then Norfolk and Western from Lynchburg to Bristol. At Bristol it would again become Southern RR.
One train would be the Birmingham Special lv NYC at 12.30 noon, arrive Decatur the next afternoon at 12.07. Coach passengers change in Washington and Chattanooga. Pullman passengers change in Chattanooga.
Another would be the Memphis Special (to become known in 1941 as the Tennessean), lv NYC 12.50 am arrive Decatur 2.15 am the second night. Coach passengers would change in Washington, pullman passengers would not change at all.
Then there was a route from NYC to Cincinnati via the Pennsylvania RR, then Louisville and Nashville from Cincinnati to Decatur. My closest timetable for this is 1935.
One train is the New Orleans Limited from Cincinnati to Decatur, I do not know the Pennsylvania name from NYC to Cincinnati. The schedule was to leave NYC 11 pm arrive Decatur the second morning at 5.30.Pullman passengers would not change but coach passengers would change in Cincinnati.
Another train on this route would be called the Pan American for the Cincinnati to Decatur portion. It would leave NYC 3:55 pm arrive Decatur the next night at 7.17. Change in Cincinnati for both coach and pullman. You could ride a pullman through from NYC to Decatur but it would be much slower than transferring to the Pan American in Cincy It would mean arriving the second morning at 3.
Do not hesitate to PM me if you want more details.