The Refrigerated Boxcar

From Wikipedia

A refrigerator car (or "reefer") is a refrigerated boxcar (U.S.), a piece of railroad rolling stock designed to carry perishable freight at specific temperatures. Refrigerator cars differ from simple insulated boxcars and ventilated boxcars (commonly used for transporting fruit), neither of which are fitted with cooling apparatus. Reefers can be ice-cooled, come equipped with any one of a variety of mechanical refrigeration systems, or utilize carbon dioxide (either as dry ice, or in liquid form) as a cooling agent.

Early attempts at refrigerated transport

During the mid-19th century, attempts were made to ship agricultural products by rail. As early as 1842, the Western Railroad of Massachusetts was reported in the June 15 edition of the Boston Traveler to be experimenting with innovative freight car designs capable of carrying all types of perishable goods without spoilage. The first refrigerated boxcar entered service in June 1851, on the Northern Railroad.

This "icebox on wheels" was a limited success since it was only functional in cold weather. That same year, the Ogdensburg and Lake Champlain Railroad (O&LC) began shipping butter to Boston in purpose-built freight cars, utilizing ice for cooling

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 refer required re-icing every 250 miles to 400 miles. Top icing is the practice of placing a 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 40-foot (12 m) reefer required in excess of 10,000 pounds (4,500 kg) 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.

Refrigerator cars required effective insulation to protect their contents from temperature extremes. "Hairfelt" derived from compressed cattle hair, sandwiched into the floor and walls of the car, was inexpensive, yet flawed over its three- to four-year service life it would decay, rotting out the car's wooden partitions and tainting the cargo with a foul odor. The higher cost of other materials such as "Linofelt" (woven from flax fibers) or cork prevented their widespread adoption. Synthetic materials such as fiberglass and polystyrene foam, both introduced after World War II, offered the most cost-effective and practical solution.

In the latter half of the 20th century, mechanical refrigeration began to replace ice-based systems. Soon after, mechanical refrigeration units replaced the armies of personnel required to re-ice the cars.

The sliding plug door was introduced experimentally by Pacific Fruit Express in April 1945. This type of door provided a larger six-foot opening to facilitate car loading and unloading. These tight-fitting doors were better insulated and could maintain an even temperature inside the car. By the mid-1970s, the few remaining ice bunker cars were relegated to "top-ice" service, where crushed ice was applied atop the commodity.

Hopper cars

In 1969, the Northern Pacific Railroad ordered a number of modified covered hopper cars from American Car and Foundry for transporting perishable food in bulk. The 55-foot-long cars were blanketed with a layer of insulation, equipped with roof hatches for loading, and had centerflow openings along the bottom for fast discharge. A mechanical refrigeration unit was installed at each end of the car, where sheet metal ducting forced cool air into the cargo compartments.

The units, rated at 100 short tons capacity (more than twice that of the largest conventional refrigerator car of the day) were economical to load and unload, as no secondary packaging was required. Apples, carrots, onions, and potatoes were transported in this manner with moderate success The Santa Fe Railway leased 100 of the hoppers from ACF, and in April 1972 purchased 100 new units, known as "Conditionaire" cars.

When did the Ice Box first make its way into the kitchens of Florida?

After the railroad started to provide ice!