   #copyright

Refrigerator car

2007 Schools Wikipedia Selection. Related subjects: Railway transport

   A World War II-era wood-sided, ice bunker "reefer" of the American
   Refrigerator Transit Company (ART), one specially-designated for the
   transport of dairy products, circa 1940.
   Enlarge
   A World War II-era wood-sided, ice bunker "reefer" of the American
   Refrigerator Transit Company (ART), one specially-designated for the
   transport of dairy products, circa 1940.

   A refrigerator car (or "reefer") is a refrigerated boxcar, 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. Milk cars (and other types of "express"
   reefers) may or may not include a cooling system, but are equipped with
   high-speed wheelsets and other modifications that allow them to travel
   with passenger trains.

   Reefer applications can be divided into four broad groups: 1) dairy and
   poultry producers require refrigeration and special interior racks; 2)
   fruit and vegetable reefers tend to see seasonal use, and are generally
   used for long-distance shipping (for some shipments, only ventilation
   is necessary to remove the heat in transit created by the ripening
   process); 3) manufactured foods (such as canned goods and candy) as
   well as beer and wine do not require refrigeration, but do need the
   protection of an insulated car; and 4) meat reefers come equipped with
   specialized beef rails for handling sides of meat, and brine-tank
   refrigeration to provide lower temperatures (most of these units are
   either owned or leased by meat packing firms).

History

Background

   Illinois Central Railroad #14713, a ventilated fruit car dating from
   1893.
   Enlarge
   Illinois Central Railroad #14713, a ventilated fruit car dating from
   1893.

   Following the end of the American Civil War, Chicago, Illinois emerged
   as a major railway centre for the distribution of livestock raised on
   the Great Plains to Eastern markets. Getting the animals to market
   required herds to be driven distances of up to 1,200 miles (2,000 km)
   to railheads in Kansas City, Missouri, whereupon they were loaded into
   specialized stock cars and transported live ("on-the-hoof") to regional
   processing centers. Driving cattle across the plains also led to
   tremendous weight loss, and a number of animals were typically lost
   along the way.

   Upon arrival at the local processing facility, livestock were either
   slaughtered by wholesalers and delivered fresh to nearby butcher shops
   for retail sale, smoked, or packed for shipment in barrels of salt.
   Certain costly inefficiencies were inherent in the process of
   transporting live animals by rail, particularly the fact that about
   sixty percent of the animal's mass is inedible. The death of animals
   weakened by the long drive further increased the per-unit shipping
   cost. Meat packer Gustavus Swift began looking for a way to ship
   dressed meats from his packing plant in Chicago to the East.

Early attempts at refrigerated transport

   An advertisement taken from the 1st edition (1879) of the Car-Builders
   Dictionary for the Tiffany Refrigerator Car Company, a pioneer in the
   design of refrigerated railroad cars.
   Enlarge
   An advertisement taken from the 1st edition (1879) of the Car-Builders
   Dictionary for the Tiffany Refrigerator Car Company, a pioneer in the
   design of refrigerated railroad cars.

   A number of attempts were made during the mid-1800s to ship
   agricultural products via rail car. 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 of New York (or NRNY, which later became part of the Rutland
   Railroad). This "icebox on wheels" was a limited success in that it was
   only able to function 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 to cool the contents.

   The first consignment of dressed beef to ever leave the Chicago
   stockyards did so in 1857, and was carried in ordinary boxcars
   retrofitted with bins filled with ice. Placing the meat directly
   against ice resulted in discoloration and affected the taste, however,
   and therefore proved to be impractical. During the same period Swift
   experimented by moving cut meat using a string of ten boxcars which ran
   with their doors removed, and made a few test shipments to New York
   during the winter months over the Grand Trunk Railway (GTR). The method
   proved too limited to be practical.
   The interior of a typical ice-bunker reefer from the 1920s; the wood
   sheathing would give way to plywood within twenty years. Vents in the
   bunker at the end of the car, along with slots in the wood floor racks,
   allowed cool air to circulate around the contents during transit.
   Enlarge
   The interior of a typical ice-bunker reefer from the 1920s; the wood
   sheathing would give way to plywood within twenty years. Vents in the
   bunker at the end of the car, along with slots in the wood floor racks,
   allowed cool air to circulate around the contents during transit.

   Detroit's William Davis patented a refrigerator car that employed metal
   racks to suspend the carcasses above a frozen mixture of ice and salt.
   He sold the design in 1868 to George H. Hammond, a Detroit meat-packer,
   who built a set of cars to transport his products to Boston using ice
   from the Great Lakes for cooling. The loads had the unfortunate
   tendency of swinging to one side when the car entered a curve at high
   speed, and the use of the units was discontinued after several
   derailments. Finally, in 1878, Swift hired engineer Andrew Chase to
   design a ventilated car that was well-insulated, and positioned the ice
   in a compartment at the top of the car, allowing the chilled air to
   flow naturally downward. The meat was packed tightly at the bottom of
   the car to keep the centre of gravity low and to prevent the cargo from
   shifting. Chase's design proved to be a practical solution to providing
   temperature-controlled carriage of dressed meats, and allowed Swift and
   Company to ship their products all over the United States and
   internationally.

   Swift's attempts to sell Chase's design to the major railroads were
   unanimously rebuffed, as the companies feared that they would
   jeopardize their considerable investments in stock cars, animal pens,
   and feedlots if refrigerated meat transport gained wide acceptance. In
   response, Swift financed the initial production run on his own, then —
   when the American roads refused his business — he contracted with the
   GTR (a railroad that derived little income from transporting live
   cattle) to haul the cars into Michigan and then eastward through
   Canada. In 1880, the Peninsular Car Company (subsequently purchased by
   ACF) delivered to Swift the first of these units, and the Swift
   Refrigerator Line (SRL) was created. Within a year the Line’s roster
   had risen to nearly 200 units, and Swift was transporting an average of
   3,000 carcasses a week to Boston, Massachusetts. Competing firms such
   as Armour and Company quickly followed suit. By 1920 the SRL owned and
   operated 7,000 of the ice-cooled rail cars; the General American
   Transportation Corporation would assume ownership of the line in 1930.
   A builder's photo of one of the first refrigerator cars to come out of
   the Detroit plant of the American Car and Foundry Company (ACF), built
   in 1899 for the Swift Refrigerator Line.
   Enlarge
   A builder's photo of one of the first refrigerator cars to come out of
   the Detroit plant of the American Car and Foundry Company (ACF), built
   in 1899 for the Swift Refrigerator Line.

   Live cattle and dressed beef deliveries to New York ( short tons):
            (Stock Cars)  (Refrigerator Cars)
     Year   Live Cattle      Dressed Beef
     1882      366,487           2,633
     1883      392,095          16,365
     1884      328,220          34,956
     1885      337,820          53,344
     1886      280,184          69,769

   The subject cars travelled on the Erie, Lackawanna, New York Central,
   and Pennsylvania railroads.

   Source: Railway Review, January 29, 1887, p. 62.
   A circa 1870 refrigerator car design. Hatches in the roof provided
   access to the ice tanks at each end.
   Enlarge
   A circa 1870 refrigerator car design. Hatches in the roof provided
   access to the ice tanks at each end.

   19th Century American Refrigerator Cars:
     Year   Private Lines   Railroads      Total
     1880     1,000 est.        310     1,310 est.
     1885     5,010 est.        990     6,000 est.
     1890     15,000 est.      8,570    23,570 est.
     1895     21,000 est       7,040    28,040 est.
     1900     54,000 est.     14,500    68,500 est.

   Source: Poor's Manual of Railroads and ICC and U.S. Census reports.

The "Ice Age"

   The use of ice to refrigerate and thus preserve food dates back to
   prehistoric times. Through the ages, the seasonal harvesting of snow
   and ice was a regular practice of many ancient cultures: China, Greece,
   and Rome (to name a few) all stored ice and snow in caves or dugouts
   lined with straw or other insulating materials. Rationing of the ice
   allowed the preservation of foods over the hot periods, a practice that
   was successfully employed for centuries. For most of the 1800s, natural
   ice (harvested from ponds and lakes) was used to supply the various
   refrigerator car lines. 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 months and stored in
   insulated warehouses for use during the rest of the year, where sawdust
   and hay was packed around the ice blocks to provide additional thermal
   protection. A late-19th century model wood-bodied reefer required
   re-icing every 250 to 400 miles.
   Top icing of bagged vegetables in a refrigerator car.
   Enlarge
   Top icing of bagged vegetables in a refrigerator car.

   By the turn of the century, artificially-produced ice became more
   common. The Pacific Fruit Express (PFE), for example, maintained 7
   natural harvesting facilities, and operated 18 artificial ice plants.
   Their largest plant (located in Roseville, California) produced 1,200
   short tons of ice each day; Roseville’s docks could accommodate up to
   254 cars at a time. At the industry’s peak, 13 million short tons of
   ice was produced for refrigerator car use every year.

"Top Icing"

   Top icing is the practice of placing a 2- to 4-inch layer of crushed
   ice over the 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). In
   practice, 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 reefer required in excess of 10,000 pounds 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 altogether.

   Men harvest ice on Michigan's Lake Saint Clair, circa 1905. The ice
   would be cut into blocks and hauled by wagon to a specially-designed
   cold storage warehouse, and held until needed.

   Ice blocks (also called "cakes") are manually placed into reefers from
   a covered icing dock. Each block weighed between 200 and 400 pounds;
   crushed ice was typically used for meat cars.

   An early version of a field icing car loads a Merchants Despatch
   Transportation Co. reefer (bearing the herald of the GM&O) in Norfolk,
   Virginia on April 19, 1955.

   The "business end" of a mechanical ice loading system services a line
   of Pacific Fruit Express refrigerator cars. Each car will require
   approximately 5½ short tons (5 metric tons) of ice.
   Workmen top off a reefer's top-mounted bunkers with crushed ice.
   Enlarge
   Workmen top off a reefer's top-mounted bunkers with crushed ice.

   The typical service cycle for an ice-cooled produce reefer (generally
   handled as a part of a block of cars):
    1. The cars were cleaned with hot water or steam.
    2. Depending on the cargo, the cars might have undergone 4 hours of
       "pre-cooling" prior to loading, which entailed blowing in cold air
       through one ice hatch and allowing the warmer air to be expelled
       through the other hatches. The practice (which dates back almost to
       the inception of the refrigerator car) saved ice and resulted in
       fresher cargo.
    3. The cars' ice bunkers were filled, either manually from an icing
       dock, via mechanical loading equipment, or (in locations where
       demand for ice was sporadic) using specially-designed field icing
       cars.
    4. The cars were delivered to the shipper for loading, and the ice was
       topped-off.
    5. Depending on the cargo and destination, the cars may have been
       fumigated.
    6. The train would depart for the eastern markets.
    7. The cars were re-iced in transit approximately once a day.
    8. Upon reaching their destination, the cars were unloaded.
    9. If in demand, the cars would be returned to their point-of-origin
       empty; if not in demand, the cars would be cleaned and (if
       possible) used for a dry shipment.

   This engraving of Tiffany’s original "Summer and Winter Car" appeared
   in the Railroad Gazette just before Joel Tiffany received his
   refrigerator car patent in July, 1877. Tiffany's design mounted the ice
   tank in a clerestory atop the car's roof, and relied on a train's
   motion to circulate cool air throughout the cargo space.

   A Pullman-built "shorty" reefer bears the Armour Packing Co.   ·
   Kansas City logo, circa 1885. The name of the "patentee" was displayed
   on the car's exterior, a practice intended to "...impress the shipper
   and intimidate the competition...," even though most patents covered
   trivial or already-established design concepts.

   A rare double-door refrigerator car utilized the "Hanrahan System of
   Automatic Refrigeration" as built by ACF, circa 1898. The car had a
   single, centrally-located ice bunker which was said to offer better
   cold air distribution. The two segregated cold rooms were well-suited
   for less-than-carload (LCL) shipments.

   A pre- 1911 "shorty" reefer bears an advertisement for Anheuser-Busch's
   Malt Nutrine tonic. The use of similar "billboard" advertising on
   freight cars was banned by the Interstate Commerce Commission in 1937,
   and thereafter cars so decorated could no longer be accepted for
   interchange between roads.

   Refrigerator cars required effective insulation to protect their
   delicate contents from temperature extremes. " Hairfelt" derived from
   compressed cattle fur, sandwiched into the floor and walls of the car,
   was inexpensive but 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 odour in the process. The relatively higher cost
   of other less sensitive materials such as "Linofelt" (woven from flax
   fibers) or cork prevented their widespread adoption. Synthetic
   materials such as fibreglass and polystyrene, both introduced after
   World War II, offered the most cost-effective and practical solution.

Mechanical refrigeration

   In the latter half of the 20th century mechanical refrigeration began
   to replace ice-based systems. The mechanical refrigeration units proved
   their worth in replacing the "armies" of personnel that were no longer
   needed to re-ice the cars periodically. In the 1960s the "plug" door
   was introduced as an option that provided a larger opening to better
   facilitate loading and unloading of cargo. These tight-fitting doors
   were better insulated and could therefore maintain a more even
   temperature inside the car. By the mid-1970s those few ice bunker cars
   that were still active were relegated to "top-ice" service wherein
   crushed ice was applied on top of the commodity itself once loaded.

   A cutaway illustration of a conventional mechanical refrigerator car,
   which typically contains in excess of 800 moving parts.

   A modern refrigerator car: note the grill at the lower right (the car's
   "A" end) where the mechanical refrigeration unit is housed.

   State-of-the-art mechanical refrigerator car designs place the
   removable, end-mounted refrigeration unit outside of the freight
   compartment in order to facilitate access for servicing or replacement.

   A modern mechanical refrigerator car, outfitted for high-speed service,
   bears the colors and markings of Amtrak Express, Amtrak's freight and
   shipping service.

Cryogenic refrigeration

   Cryogenic refrigerator cars, such as those owned and operated by
   Cryo-Trans, Inc., are still used today to transport frozen food
   products, including french fries. Today, Cryo-Trans operates a fleet in
   excess of 515 cryogenic railcars.
   Enlarge
   Cryogenic refrigerator cars, such as those owned and operated by
   Cryo-Trans, Inc., are still used today to transport frozen food
   products, including french fries. Today, Cryo-Trans operates a fleet in
   excess of 515 cryogenic railcars.

   The Topeka, Kansas shops of the Santa Fe Railway built five
   experimental refrigerator cars employing liquid nitrogen as the cooling
   agent in 1965. A fine mist of liquified nitrogen was released
   throughout the car if the temperature rose above a pre-determined
   level. Each car carried 3,000 pounds (1,360 kg) of refrigerant and
   could maintain a temperature of minus 20 degrees Fahrenheit (−30 °C).
   During the 1990s, a few railcar manufacturers experimented with the use
   of liquid carbon dioxide (CO[2]) as a cooling agent. The move was in
   response to rising fuel costs, and was an attempt to eliminate the
   standard mechanical refrigeration systems that required periodic
   maintenance. The CO[2] system can keep the car's load frozen solid for
   periods as long as 14 to 16 days, if necessary.

   Several hundred " cryogenic" refrigerator cars were placed into service
   transporting frozen foodstuffs, though they failed to gain wide
   acceptance (due, in part, to the steadily-rising cost of liquid carbon
   dioxide). Since cryogenic refrigeration is a proven technology and
   environmentally friendly, the rising price of fuel and the increased
   availability of carbon dioxide from Kyoto Protocol-induced capturing
   techniques may lead to a resurgence in cryogenic railcar usage.
   Cryo-Trans, Inc. (founded in 1985) has since dedicated 200 of its
   refrigerated cars to wine transportation service.

Experimentation

Aluminium and stainless steel

   In 1946, the Pacific Fruit Express procured from the Consolidated Steel
   Corporation of Wilmington, California two 40-foot aluminium-bodied
   ventilator refrigerator cars, in order to compare the durability of the
   lightweight alloy versus that of steel. It was hoped that weight
   savings (the units weighed almost 10,000 pounds less than a like-sized
   all-steel car) and better corrosion resistance would offset the higher
   initial cost. One of the aluminium car bodies was manufactured by Alcoa
   (PFE #44739), while the other was built by the Reynolds Aluminium
   Company (PFE #45698).

   The cars (which were outfitted with state-of-the-art fibreglass
   insulation and fans driven by the car's axles 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 efforts. 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 aluminium reefers were ever
   constructed, cost being the likely reason. Also in 1946, the
   Consolidated Steel delivered the world's only reefer to have a
   stainless steel car body to the Santa Fe Refrigerator Despatch. The
   40-foot car was equipped with convertible ice bunkers, side ventilation
   ducts, and axle-driven circulation fans. 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. That number conflicted with a
   Santa Fe passenger car, and was given #4150 in 1955.

   #4150 spent most of its life in express service. Cost was cited as the
   reason no additional units were ever ordered. The car was dismantled at
   Clovis, New Mexico in February, 1964.

"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 22- foot-long,
   all-steel car that resembled the forty-and-eights used in Europe during
   World War I. The prototype weighed in at 13½ tons and was outfitted
   with a 1,500- pound ice bunker at each end. The car was leased to
   Hormel and saw service between Chicago, Illinois and the southern
   United States. However, the concept failed to gain acceptance with the
   big eastern railroads and therefore 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
   minus 109 degrees Fahrenheit (versus 32 degrees above zero 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 from
   gaining acceptance over conventional ice. Worst of all, it was found
   that dry ice can adversely affect the colour and flavor of certain
   foods if placed in too close a proximity to them.

Hopper cars

   In 1969, the Burlington Northern 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, were equipped with roof hatches for loading, and
   had centerflow openings along the bottom to allow for fast discharge of
   the contents. A mechanical refrigeration unit was installed at each end
   of the car, where sheet metal ducting forced the cool air into the
   cargo compartments.

   The units, which were rated at 100 short tons load carrying capacity
   (more than twice that provided by the largest conventional refrigerator
   car of the day) were obviously economical to load and unload, as no
   secondary packaging was required. Apples, carrots, onions, and potatoes
   were transported in this manner with some success. Oranges, on the
   other hand, tended to burst under their own weight, even after wooden
   baffles were installed to better distribute the load. The Santa Fe
   Railway leased 100 of the hoppers from ACF, and in April, 1972
   purchased 100 new units. The cars' irregular, orange-colored outer
   surface (though darker in shade than the standard AT&SF yellow-orange
   used on reefers) tended to collect dirt easily, and proved difficult to
   clean as well. Santa Fe eventually relegated the cars to more typical,
   non-refrigerated applications.

Timeline

     * 1842: The Western Railroad of Massachusetts experiments with
       innovative freight car designs capable of carrying all types of
       perishable goods without spoilage.
     * 1851: The first refrigerated boxcar enters service on the Northern
       Railroad of New York.
     * 1857: The first consignment of refrigerated, dressed beef travels
       from Chicago stockyards to the East Coast in ordinary box cars
       packed with ice.
     * 1866: Horticulturist Parker Earle ships strawberries in iced boxes
       by rail from southern Illinois to Chicago on the Illinois Central
       Railroad.
     * 1868: William Davis of Detroit, Michigan develops a refrigerator
       car cooled by a frozen ice-salt mixture, and patents it in the U.S.
       The patent is subsequently sold to George Hammond, a local meat
       packer who goes on to amass a fortune in refrigerated shipping.
     * 1876: German engineer Carl von Linde develops one of the first
       mechanical refrigeration systems.
     * 1878: Gustavus Swift (along with engineer Andrew Chase) develops
       the first practical ice-cooled railcar; soon thereafter, Swift
       forms the Swift Refrigerator Line (SRL), the world's first.
     * 1880: The first patent for a mechanically-refrigerated railcar
       issued in the United States is granted to Charles William Cooper.
     * 1884: The Santa Fe Refrigerator Despatch (SFRD) is established as a
       subsidiary of the Atchison, Topeka and Santa Fe Railway to carry
       perishable commodities.
     * 1885: Berries from Norfolk, Virginia are shipped by refrigerator
       car to New York.
     * 1887 Parker Earle joined F.A. Thomas of Chicago in the fruit
       shipping business. The company owned 60 ice-cooled railcars by
       1888, and 600 by 1891.
     * 1888: Armour & Co. ships beef from Chicago to Florida in a car
       cooled by ethyl chloride-compression machinery. Florida oranges are
       shipped to New York under refrigeration for the first time.
     * 1889: The first cooled shipment of deciduous fruit from California
       is sold on the New York market.
     * 1898: Russia's first refrigerator cars enter service. The country's
       inventory will reach 1,900 by 1908, grow to 3,000 just two years
       later, and top out at approximately 5,900 by 1916. The cars were
       utilized mainly for transporting butter from Siberia to the Baltic
       Sea (a 12-day journey).
     * 1899: Refrigerated fruit traffic within the U.S. reaches 90,000
       short tons per year; Transport from California to NY averaged 12
       days in 1900.
     * 1901: Carl von Linde equips a Russian train with a mobile, central
       mechanical refrigeration plant to distribute cooling to cars
       carrying perishable goods; similar systems will be used in Russia
       as late as 1975.
     * 1905: U.S. traffic in refrigerated fruit reaches 430,000 short
       tons. As refrigerator car designs become standardized, the practice
       of indicating the "patentee" on the sides is discontinued.
     * 1907: The Pacific Fruit Express begins operations with more than
       6,000 refrigerated cars, transporting fruit and vegetables across
       the United States from Western producers to Eastern consumers. U.S.
       traffic in refrigerated fruit hits 600,000 short tons.
     * 1913: The number of thermally-insulated railcars (most of which
       were cooled by ice) in the U.S. tops 100,000.
     * 1920: The Fruit Growers Express (or FGE, a former subsidiary of the
       Armour Refrigerator Line) is formed using 4,280 reefers acquired
       from Armour & Co.
     * 1923: FGE and the Great Northern Railway for the Western Fruit
       Express (WFE) in order to compete with the Pacific Fruit Express
       and Santa Fe Refrigerator Despatch in the West.
     * 1925–1930: Mechanically-refrigerated trucks enter service and gain
       public acceptance, particularly for the delivery of milk and ice
       cream.
     * 1926: The FGE expands its service into the Pacific Northwest and
       the Midwest through the WFE and the Burlington Refrigerator Express
       Company (BREX), its other partly-owned subsidiary. FGE purchases
       2,676 reefers from the Pennsylvania Railroad.
     * 1928: The FGE forms the National Car Company as a subsidiary to
       service the meat transportation market; customers include Kahns,
       Oscar Mayer, and Rath.
     * 1930: The number of refrigerator cars in the United States reaches
       its maximum of approximately 183,000 units.
     * 1931: The SFRD reconfigures 7 reefers to utilize dry ice as a
       cooling agent.
     * 1936: The first all-steel reefers enter service.
     * 1937: The Interstate Commerce Commission bans "billboard" type
       advertisements on railroad cars.
     * 1946: Two experimental aluminium-body refrigerator cars enter
       service on the PFE; an experimental reefer with a stainless-steel
       body is built for the SFRD.
     * 1950: The U.S. refrigerator car roster drops to 127,200.
     * 1957: The last ice bunker refrigerator cars are built.
     * 1958: The first mechanical reefers (utilizing diesel-powered
       refrigeration units) enter revenue service.
     * 1960s: The flush, "plug" style sliding door is introduced as an
       option that provides a larger door to ease loading and unloading of
       certain commodities. The tight-fitting doors are better insulated
       and allow a car's interior to be maintained at a more even
       temperature.
     * 1969: ACF constructs a number of experimental centre flow hopper
       cars which incorporate mechanical cooling systems and insulated
       cargo cells; the units are intended for shipment of bulk
       perishables.
     * 1971: The last ice-cooled reefers are retired from service.
     * 1980: The U.S. refrigerator car roster drops to 80,000.
     * 1990s: The first cryogenically-cooled reefers enter service.
     * 2001: The number of refrigerator cars in the United States "bottoms
       out" at approximately 8,000.
     * 2005: The number of reefers in the United States climbs to
       approximately 25,000, the result of significant new refrigerator
       car orders.

Specialized applications

Express service

   An REA express reefer is positioned at the head end of Santa Fe train
   No.8, the Fast Mail Express, in 1965.
   Enlarge
   An REA express reefer is positioned at the head end of Santa Fe train
   No.8, the Fast Mail Express, in 1965.

   Standard refrigerated transport is often utilized for good with less
   than 14 days of refrigerated "shelf life": avocados, cut flowers, green
   leafy vegetables, lettuce, mangos, meat products, mushrooms, peaches
   and nectarines, pineapples and papayas, sweet cherries, and tomatoes.
   "Express" reefers are typically employed in the transport of special
   perishables: commodities with a refrigerated shelf life of less than 7
   days such as human blood, fish, green onions, milk, strawberries, and
   certain pharmaceuticals.

   The earliest express-service refrigerator cars entered service around
   1890, shortly after the first express train routes were established in
   North America. The cars did not, however, come into general use until
   the early 20th century. Most units designed for express service are
   larger than their standard counterparts, and are typically constructed
   more along the lines of baggage cars than freight equipment. Cars must
   be equipped with speed-rated trucks and brakes, and — if they are to be
   run ahead of the passenger car consist — must also incorporate an air
   line for pneumatic braking, a communication signal air line, and a
   steam line for train heating. Express units were typically painted in
   passenger car colors, such as Pullman green.

   The first purpose-built express reefer emerged from the Erie Railroad's
   Susquehanna Shops on August 1, 1886. By 1927, some 2,218 express cars
   traveled over America's rails; three years later, that number had grown
   to 3,264. In 1940, private rail lines began to build and operate their
   own reefers, the Railway Express Agency (REA) being by far the largest.
   In 1948, the REA roster (which would continue to expand into the 1950s)
   numbered approximately 1,800 cars, many of which were World War II
   "troop sleepers" modified for express refrigerated transport. By 1965,
   due to an industry-wide decline in refrigerated rail traffic, many
   express reefers were found in lease service to railroad companies for
   use as bulk mail carriers.
   Pacific Fruit Express #722, an ice-cooled, express-style refrigerator
   car designed to carry milk in stainless steel cans and other
   highly-perishable cargo at the head end of passenger train consists.
   Enlarge
   Pacific Fruit Express #722, an ice-cooled, express-style refrigerator
   car designed to carry milk in stainless steel cans and other
   highly-perishable cargo at the head end of passenger train consists.
   Railway Express Agency refrigerator car #6687, a converted World War II
   "troop sleeper." Note the square panels along the sides that cover the
   former window openings.
   Enlarge
   Railway Express Agency refrigerator car #6687, a converted World War II
   "troop sleeper." Note the square panels along the sides that cover the
   former window openings.

Intermodal

   An intermodal train containing mechanically-cooled highway trailers in
   "piggyback" service passes through the Cajon Pass in February, 1995.
   Enlarge
   An intermodal train containing mechanically-cooled highway trailers in
   "piggyback" service passes through the Cajon Pass in February, 1995.

   For many years, virtually all of the perishable traffic in the United
   States belonged to the railroads. But while the railroads were subject
   to government regulation regarding shipping rates, trucking companies
   could set their own rate for hauling agricultural products, giving them
   a competitive edge. In March, 1979 the ICC exempted rail transportation
   of fresh fruits and vegetables from all economic regulation. Once the
   "Agricultural Exemption Clause" was removed from the Interstate
   Commerce Act, railroad companies began aggressively pursuing
   trailer-on-flatcar (TOFC) business (a form of intermodal freight
   transport) for refrigerated trailers. Taking this strategy one step
   further, a number of carriers (including the PFE and SFRD) purchased
   their own refrigerated trailers in order to compete directly with
   interstate trucking concerns.

   The final chapter has not, as many industry insiders have predicted,
   been written for the refrigerator car in America. The dawn of the 21st
   century has seen the first significant reefer orders since the early
   1970s.

Tropicana "Juice Train"

   Tropicana #3053, one of the cars of the "Great White Fleet."
   Enlarge
   Tropicana #3053, one of the cars of the "Great White Fleet."

   In 1970, Tropicana orange juice was shipped in bulk via insulated
   boxcars in one weekly round-trip from Florida to Kearny, New Jersey. By
   the following year, the company was operating two 60-car unit trains a
   week, each carrying around 1 million U.S. gallons (4 million liters) of
   juice. On June 7, 1971 the "Great White Juice Train" (the first unit
   train in the food industry, consisting of 150 one hundred short ton
   insulated boxcars fabricated in the Alexandria, Virginia shops of Fruit
   Growers Express) commenced service over the 1,250- mile (2,000-
   kilometer) route. An additional 100 cars were soon incorporated into
   the fleet, and small mechanical refrigeration units were installed to
   keep temperatures constant on hot days. Tropicana saved $40 million in
   fuel costs alone during the first ten years in operation.

AAR classificatons

   Class Description Class Description
     RA Brine-tank ice bunkers   RPB Mechanical refrigerator with
   electro-mechanical axle drive
     RAM Brine-tank ice bunkers with beef rails   RPL Mechanical
   refrigerator with loading devices
     RAMH   Brine-tank with beef rails and heaters   RPM Mechanical
   refrigerator with beef rails
     RB No ice bunkers — heavy insulation   RS Bunker refrigerator —
   common ice bunker car
     RBL No ice bunkers and loading devices   RSB Bunker refrigerator —
   air fans and loading devices
     RBH No ice bunkers — gas heaters   RSM Bunker refrigerator with beef
   rails
     RBLH No ice bunkers — loading devices and heaters   RSMH   Bunker
   refrigerator with beef rails and heaters
     RCD Solid carbon-dioxide refrigerator   RSTC Bunker refrigerator —
   electric air fans
     RLO Special car type — permanently-enclosed (covered hopper type)
     RSTM Bunker refrigerator — electric air fans and beef rails
     RP Mechanical refrigerator

     Note: Class B refrigerator cars are those designed for passenger
   service; insulated boxcars are designated Class L.

     Source: The Great Yellow Fleet, p. 126.
   Retrieved from " http://en.wikipedia.org/wiki/Refrigerator_car"
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   with only minor checks and changes (see www.wikipedia.org for details
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