This image of Southern Railway PS-4 Pacific No. 1406, by Shelby Lowe, comes from the collection of Tom Rock of T.D.R. Productions. Date and location are unspecified. No. 1406 belonged to the last group of five PS-4s, delivered in 1929; note the eight-wheel tender in contrast to the twelve-wheel tender of No. 1404. The grate area of the PS-4 class totaled 71 square feet. Their evaporative heating surface was 3690 square feet, and their superheating surface 905 square feet. The PS-4 was a refinement of the USRA heavy Pacific design, the principal modification being a reduction of the driver diameter from 79 to 73 inches.