Photo courtesy of Don DeLay. A Peter Arnold photo taken in May 1974, one year after the ICC allow discontinuance of in-transit icing of reefers.
SFRD 3436 is a class Rr-52 ice bunker reefer, one of 220 built new by the Santa Fe Wichita Shops in 1952-53, series 3280-3499. Notice the "conventional" hatch covers which open inboard of the car roof.
These cars differed in only a few details from the Class Rr-47 cars and, according to the Santa Fe reefer book, were virtually identical to the ARA rebuilds of the Rr-49, -50 and -51 classes.
By 1968 there were 195 cars in this class on the roster. That dropped to 137 in 1971 and just 28 in 1974. The remaining Rr-52 cars were retired in that same year and were among the last ice bunker refrigerator cars in revenue service on the Santa Fe.
There are several photo examples of Rr-52 reefers in the book, Santa Fe Refrigerator Cars: Ice Bunker Cars 1884-1979.
Bob Chaparro