It was thought that stainless steel would better resist the corrosive deterioration resulting from salting the ice. The one-of-a-kind unit entered service as #13000, but was subsequently redesignated as #1300, and later given #4150 in 1955. The car spent most of its life in express service. Cost was cited as the reason no additional units were ordered. The car was dismantled at Clovis, New Mexico in February 1964. Pacific Fruit Express rebuilt two steel-sided ventilator refrigerator cars in their Los Angeles shops with aluminum car bodies to test durability of lightweight alloys versus that of steel. It was hoped that weight savings (the units weighed almost less than a like-sized all-steel car) and better corrosion resistance would offset the higher initial cost. Alcoa provided the body for number 44739, and Reynolds Aluminum Company provided number 45698. The cars (outfitted with state-of-the-art fiberglass insulation and axle-driven fans for internal air circulation) traveled throughout the Southern Pacific and Union Pacific systems, where they were displayed to promote PFE's post-World War II modernization. Though both units remained in service over 15 years (#45698 was destroyed in a wreck in May 1962, while #44739 was scrapped in 1966), no additional aluminum reefers were constructed. Fruit Growers Express number 38374 was equipped with an experimental aluminum body in the Indiana Harbor, Indiana shops. "Depression Baby" During the 1930s, the North American Car Company produced a one-of-a-kind, four-wheeled ice bunker reefer intended to serve the needs of specialized shippers who did not generate sufficient product to fill a full-sized refrigerator car. NADX #10000 was a -long, all-steel car that resembled the forty-and-eights used in Europe during World War I. The prototype weighed and was outfitted with a ice bunker at each end. The car was leased to Hormel and saw service between Chicago, Illinois and the southern United States. The concept failed to gain acceptance with eastern railroads and no additional units were built. Dry ice The Santa Fe Refrigerator Despatch (SFRD) briefly experimented with dry ice as a cooling agent in 1931. The compound was readily available and seemed like an ideal replacement for frozen water. Dry ice melts at (versus for conventional ice) and was twice as effective thermodynamically. Overall weight was reduced as the need for brine and water was eliminated. While the higher cost of dry ice was certainly a drawback, logistical issues in loading long lines of cars efficiently prevented it