This photo is from the Southern booklet "Southern Railway System Has the Right Car For Your Frieght" It is from my collection.

Southern's 40 - foot aluminum containers are versatile. They can be moved by rail as wheeled trailers if that will make the service more convenient for the customers. The rail - highway transfer cranes handle them with ease, wheels and all, or they may be ramp unloaded if desired. In any case, shippers enjoy the advantages of rail - highway service - lower transportation costs, lower handling costs with less chance of damage, fast flexible, dependable delivery. Southern's rail - highway specialist, whose combined total of years of experience in rail and highway transportation runs into the hundreds, work to make certain that these advantages pay off for you.