Does anyone know how common reefer traffic was on the Southern Division (Memphis to Birmingham) in the 40s and 50s? I've seen an ice dock on the track chart for East Thomas Yard (haven't seen Yale Yard yet), so that would seem to imply the division saw reefer traffic.
According to Marvin Clemons' (excellent) Birmingham Rails, the Frisco's famous fast freight, Train #138 (I may be a bit off on the number) would receive perishable traffic from the ACL.
No idea about the '40s and '50s, but in the '60s and '70s the Frisco received substantial reefer traffic off Union Pacific at Kansas City for Memphis and Birmingham, along with reefers bound for points on Seaboard Coast Line. It wouldn't surprise me if such arrangements predated the diesel era.
