SAL Train #18. The Cotton States Special leaves Birmngham Teminal Station, going to Atlanta, Georgia on 10/26/1946
The tender looks like it's bottom slopes in, or is rounded. Somewhat like a "Vanderbilt" style?
Seaboard had various styles of tenders. they had the original vanderbilt.and then they had the semi vanderbilt (as shown here) and then they had tenders similar to that of Northern Pacific (shown below)
Interesting! I've never seen much SAL steam photography.