Abstract: A refrigeration system (10) consisting of an insulated railcar (12) that utilizes sublimated carbon dioxide to maintain the integrity of stored products. The insulated railcar (12) includes a divider (22) that partitions the insulated railcar (12) into a lower storage area (26) and an upper bunker (24). The bunker (24) contains a distribution manifold (28) for forming carbon dioxide snow and distributing the formed snow throughout the bunker (24). Sublimation ports (30) along each sidewall (18) and end wall (20) allow the sublimated carbon dioxide to pass to the lower storage area (26) to refrigerate the stored products during transit. A plenum (42) and emission vent (44) is provided at each end of the insulated railcar (12) to vent sublimated carbon dioxide to the exterior atmosphere. The insulated railcar (12) also includes pressure relief ports (32) located substantially below the distribution manifold (28) to vent flash gas generated during the snow forming process.