operating and servicing refrigerated railcars, FGE became a major manufacturer of insulated boxcars and mechanical refrigerated cars. Ice The use of ice to refrigerate and preserve food dates back to prehistoric times. Through the ages, the seasonal harvesting of snow and ice was a regular practice of many cultures. China, Greece, and Rome stored ice and snow in caves, dugouts or ice houses lined with straw or other insulating materials. Rationing of the ice allowed the preservation of foods during hot periods, a practice that was successfully employed for centuries. For most of the 19th century, natural ice (harvested from ponds and lakes) was used to supply refrigerator cars. At high altitudes or northern latitudes, one foot tanks were often filled with water and allowed to freeze. Ice was typically cut into blocks during the winter and stored in insulated warehouses for later use, with sawdust and hay packed around the ice blocks to provide additional insulation. A late-19th century wood-bodied reefer required re-icing every to . Top icing is the practice of placing a to layer of crushed ice on top of agricultural products that have high respiration rates, need high relative humidity, and benefit from having the cooling agent sit directly atop the load (or within individual boxes). Cars with pre-cooled fresh produce were top iced just before shipment. Top icing added considerable dead weight to the load. Top-icing a reefer required in excess of of ice. It had been postulated that as the ice melts, the resulting chilled water would trickle down through the load to continue the cooling process. It was found, however, that top-icing only benefited the uppermost layers of the cargo, and that the water from the melting ice often passed through spaces between the cartons and pallets with little or no cooling effect. It was ultimately determined that top-icing is useful only in preventing an increase in temperature, and was eventually discontinued. The typical service cycle for an ice-cooled produce reefer (generally handled as a part of a bice was sporadic) using specially designed field icing cars. The cars were delivered to the shipper for loading, and the ice was topped-off. Depending on the cargo and destination, the cars may have been fumigated. The train would depart for the eastern markets. The cars were re-iced in transit approximately once a day. Upon reaching their destination, the cars were unloaded. If in demand, the