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Mechanical Refrigeration

This page was last updated on May 20, 2026.

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The Technology of Mechanical Refrigeration

(The focus of this page is to establish a timeline of mechanical refrigeration on U. S. railroads, 1945 to 1959, using sources not previously readily available. Sources include a wide variety of internet searches, online newspapers, and current websites and abandoned websites, and industry trade magazines at Archive.org.)

Mechanical refrigeration of the late 1940s and early 1950s required two basic components of the refrigeration unit: a refrigeration compressor, and an engine fueled by diesel or gasoline to drive the compressor. Some were direct-drive between the engine and the compressor. Others were electro-mechanical, with the engine driving a generator to create the electricity which in-turn was used to drive an electric mother that drove the compressor. Each rail car also had a fuel tank for the engine. The engine was connected to the compressor, and the two were usually mounted to a common platform to allow easy maintenance, removal and replacement. These common platforms were at times called generator sets, or gensets.

"The earliest post-war mechanical cars were built with gasoline engines directly driving refrigeration compressors. Among other things, this meant that on-off cycling of the compressor to meet a thermostat setting involved stop-start engine cycles or operation of a clutch. It was soon realized that better reliability was achieved using a small diesel engine to drive an alternator, thereby providing electric power for the compressor. This arrangement is analogous to what is done on diesel locomotives. The small diesel could run continuously, independent of refrigeration needs, and this proved a reliable and relatively economical procedure." (Tony Thompson, "PFE's mechanical reefers," Railroad Model Craftsman, January 1988; "Pacific Fruit Express," 1992, page 194, 196)

From the time of early adoption in the late 1940s and early 1950s, through to the last cars built in 1971-1973, the basic technology did not change. There were regular upgrades and rebuilding programs to modernize the fleets with better engines and better refrigeration compressors, but the concept did not change.

Then in the early 1990s, there was a move to adopt the well-established designs used in the trucking industry, which mounted a smaller and more efficient refrigeration unit (engine and compressor) to the front wall of highway trailers. The operators of large mechanical railroad refrigerator cars began limited rebuild programs to remove the older inefficient refrigerator units of the 1950s-1970s, and replace them with the trailer-style front-mount designs.

Engine Suppliers

Detroit Diesel

Railroad refrigerator cars from 1948 to 1972 were typically powered by small, reliable Detroit Diesel two-stroke engines. These engines were used to drive a generator that powered the refrigerator car's electric refrigeration system. Theses diesel engines were compact, robust, two-stroke workhorses. Their sound was distinctive. The Detroit Diesel engine had unit fuel injection and overhead valves, and was governed to run at a relatively low, constant speed of about 1200 RPM for generator duty. The Model 2-71 had two cylinders with 71 cubic inches displacement per cylinder. Their distinct sound remains the defining audio signature of a classic railroad mechanical refrigerator car.

After WWII, technological advancements made mechanical refrigeration systems practical for freight cars. This shift allowed for more reliable temperature control and larger car sizes. Instead of powering the cooling unit directly, the diesel engine drove a generator, which in turn powered the car's electric refrigeration system.

The engine and its generator were known as a "genset," typically mounted at one end of the car. The genset was a self-contained unit with a radiator for cooling, an air filter, and a fuel tank mounted on the car's underside. For maintenance, the entire unit could be slid out to hang over the trackside for routine service or completely removed for major repairs. The diesel's exhaust was routed through visible stacks on the car's roof, a key spotting feature for mechanical reefers.

These Detroit Diesel-powered reefers were a common sight across North America, used by nearly every major railroad and private car company. They were widely used by the Pacific Fruit Express (PFE), Fruit Growers Express (FGE), Santa Fe Refrigerator Despatch (SFRD), and other major lines.

Some of these Detroit Diesel-powered mechanical refrigerator cars remained in service until the 1990s. Over time, many railroads replaced the original Detroit Diesel-powered gensets with more modern, quieter, and more fuel-efficient truck-type refrigeration units (like those from Carrier Transicold).

(On Pacific Fruit Express, all mechanical refrigerator cars used Detroit Diesel model 2-71 engines except for 536 cars in 1958 that used the opposed-piston Witte, and 26 in 1961 that used Deutz engines.)

(AT&SF used Detroit Diesel 3-71 engines in their Rr-88 cars rebuilt from liquid nitrogen in 1972, and 3-53 engines in their Rr-89 and Rr-90 cars built in 1966 and 1968.)

(AT&SF records show Detroit Diesel 2044-C engines in their Rr-65 class, and 3044-A engines in their Rr-61 class, but internet searches for these model designations fails to find any additional information.)

(Some, if not all, Detroit Diesel engines for AT&SF were furnished by the Western Engine Company, a distributor of OEM Detroit Diesel engines, which assembled their own branded ready-to-run package consisting of a base engine (like the 3-53) integrated with a radiator and control panel.)

Other Small Engines

Beyond the ubiquitous Detroit Diesel units, a variety of other small gasoline and diesel engines kept the nation's produce moving in the mechanical reefer era from 1948 to 1972. Other manufacturers like Hercules, International Harvester, and Witte were all key players, alongside newer names that emerged as the technology evolved.

Several other manufacturers also supplied engines for railroad mechanical refrigerator cars. These included Hercules, as found in an AT&SF mechanical refrigerator car built in 1953, International Harvester, also used in a 1953 AT&SF car, and Witte, as used in a Pacific Fruit Express (PFE) R-70-7 car, now preserved at the Pacific Southwest Railway Museum. A later brand was Continental. An earlier brand was Buda, with its Lanova model being used in earlier mechanical refrigerator cars.

There was later competition for these small diesel engines that powered mechanical refrigeration in railroad cars. These included Caterpillar, Cummins, and Mack. While these companies' engines are not prominently listed in the primary sources for early mechanical refrigerator cars, they were powerhouses of the diesel world in the mid-20th century. It's plausible that some of their smaller industrial engines saw use, at least according to some automotive websites.

This competitive landscape began to shift in the late 1960s and 1970s as a new type of refrigeration power unit emerged; the front-mount trailer-type unit. The market moved away from the large diesel-electric generator sets toward smaller, self-contained, and quieter front-mount refrigeration units. There were early test installations on railroad cars of these "bolt-on" units similar to those used on highway trucks.

Buda-Lanova

The Buda Company of Harvey, Illinois, was a significant American manufacturer of industrial engines, both gasoline and Diesel, especially known for powering trucks, tractors, and marine vessels in the early to mid-20th century. The company was well-regarded for its reliable and innovative engines.

The company was founded in 1881 by George Chalender in the small town of Buda, Illinois. Before becoming a renowned engine maker, the company first focused on producing equipment for the railway industry, including handcars, switches, and other maintenance-of-way tools. The company's line of motorcars was eventually sold or licensed to Fairbanks-Morse.

After the move from Buda to Harvey, the Buda company continued to build hand cars. The company made many other products including railroad crossings gates, hand trucks, railbenders, scales, etc. Their main line of business centered on commercial gasoline and later, diesel engines. Many other brands of trucks, motor coaches and large motor cars used Buda engines.

(Read more about Buda engines)

Continental

(AT&SF used Continental Diesel engines and Thermo King refrigeration units in its Rr-56 class cars, built in 1955 and numbered as SFRD 2500-2510. The eleven cars were built by Santa Fe in its Wichita shops.) (This is the only known example of Continental engines being used in railroad service.)

Continental Motors Corporation had produced its first six-cylinder gasoline engine in August 1919, and the engine was used in numerous early automobiles.

"The company was founded by engineer Ross W. Judson and his brother-in-law, businessman Arthur W. Tobin in Chicago in 1902. Judson designed Continental's first commercial engine, an L-head four-cylinder, which debuted at the 1903 Chicago Automobile Show. Originally incorporated in September 1902, the company was named Autocar Equipment Co. In 1904, as the business rapidly grew, Judson and Tobin decided to focus on building engines instead of vehicles. This was then shortly renamed Continental Motor & Manufacturing Co. in February 1905 to avoid confusion with another automaker and to capitalize on the prestige associated with European engineering." "Continental first built a major plant in Muskegon, Michigan in 1905, and later expanded to Detroit. Early customers included many “assembled car” manufacturers (i.e. independent automakers who purchased major components from suppliers rather than producing them in-house)." "Continental Motors Company was a major American manufacturer of internal combustion engines, best known as an independent supplier of engines for automobiles, tractors, trucks, as well as for use with stationary equipment such as pumps, generators, and industrial machinery drives. They produced engines in the United States from 1905 through the 1960s. At its peak in the 1910s and 1920s, the company supplied engines to nearly 100 different automobile marques and powered an estimated three million cars." (Wikipedia)

(Read the Wikipedia article about Continental Motors Corporation)

Continental Motors entered the diesel engine market in 1946, 44 years after producing its first gasoline engine. Despite expectations, the company moved deliberately slowly into diesel production. This was partly due to high post-WWII demand for its gasoline engines, which strained manufacturing capacity. More importantly, Continental wanted to ensure extensive field testing and careful engineering before committing to volume diesel production. A key goal was maintaining high parts interchangeability between its new diesels and existing gasoline engines.

Continental introduced its first small diesel engines in April 1946. Designated for immediate production were five models for industrial and agricultural uses: two with four-cylinders and three with six cylinders, with S.A.E. ratings from 18 hp. to 54 hp. In the transportation line were three models, all with six cylinders, with S.A.E. ratings of 38 hp., 44 hp., and 54 hp. (Diesel Progress, April 1946)

When announced in 1946, Continental listed eight diesel models: five four- and six-cylinder engines in the 15 to 96 horsepower range for industrial and agricultural use, and three transportation engines in the 50 to 125 horsepower range. However, only three entered substantial production: the Graymarine Six-D572 (150 hp, 572 cu in, a marine version of the R-572 gasoline engine), and two four-cylinder engines – the GD-157 (157 cu in) and HD-260 (260 cu in) – which became popular in agricultural and industrial equipment.

The defining feature of Continental diesels was the "cushioned power" combustion chamber, comprising two compartments: the turbulence chamber and the Dyna-Cell. The Dyna-Cell softened peak combustion pressures, reducing noise and temporarily storing explosion energy. The turbulence chamber (a cylindrical space below the exhaust valve) created a swirling air charge around the fuel spray, producing a more homogeneous mixture. This design provided smoother, quieter operation.

Crosley

Thermo King used the Crosley Cobra gasoline engine in the early years, while the Crosley Cobra was in production from mid-1946 to early 1949. The Crosley Cobra engine used sheet metal parts in its construction, and too many did not survive the long hours of continuous operation of a railroad refrigerator car. Crosley replaced the Cobra with the CIBA, or Cast Iron Block Assembly, which was in production from 1949 to mid-1953.

Originally developed as a military generator engine during World War II, Crosley's engineers refined the engine's design for automotive use and eventually altered its construction from a brazed tin block (CoBra) to a cast-iron block (CIBA). Although the Crosley CIBA gasoline engine was designed for use in Crosley's automobiles, the engine continued to power generators, small sports car and small boat racers.

Crosley built its small gasoline engines in Cincinnati, Ohio. When the company began building automobiles, due to lack of space, it was in Marion, Indiana, 140 miles east of Cincinnati. Production of engines remained in Cincinnati until 1952 when Crosley sold the rights to the CIBA engine to General Tire, which renamed the engine the AeroJet VIP (Vertical Inline Power) and marketed it specifically as a boat engine. The AeroJet engine remained in production until about 1955 when the design was sold to Fageol, who continued to market the engine as a boat engine.

(Research suggests that Thermo King used the Crosley/AeroJet engine until 1955, with Thermo King furnishing very few refrigeration units between 1955 and the company's change from gasoline engines to Diesel engines in 1958-1959.)

(An example of the limited use on Thermo King refrigeration units on railroad cars were the 11 cars built for AT&SF in 1955. Santa Fe did not buy any additional cars with Thermo King units.)

Hercules

The Hercules Motors Corporation was organized in Canton, Ohio in 1915 to supply high-speed, lightweight gasoline engines for the fast-growing transportation industry. These engines became the standard power for the then-major independent truck manufacturers. Demand for the engines grew in other industries, including farm machinery, construction, oil-field equipment, generator sets. Hercules pioneered again in 1956 with a new line of interchangeable, overhead-valve gasoline and diesel engines with three, four, and six cylinders. Identical cylinder blocks, crankshafts, valves, connecting rods, gear covers, and bell housings were used for both gasoline and diesel engines.

The company was founded in 1915 in Canton, Ohio, under the name Hercules Motor Manufacturing Company. Its primary goal was to build industrial engines, especially for the growing trucking industry. After reorganizing in 1923, it was renamed the Hercules Motors Corporation. Its lightweight gasoline engines soon became a standard for many independent truck manufacturers and were also widely adopted in farm machinery, construction equipment, generator sets, and oil-field machinery. In 1931, Hercules pioneered high-speed, lightweight diesel engines, allowing its customers to use them without redesigning their equipment.

The Hercules Motor Corporation was a key power source for trucks during the Great Depression and a critical supplier to the Allied forces during World War II. Although its heyday was in the mid-20th century, its legacy is remembered for its powerful and reliable engines.

Hercules played a massive role in World War II, producing nearly 750,000 gasoline and diesel engines for the Allied forces. To meet wartime demand, the company expanded its capacity to 18,000 engines per month, covering all costs itself. Its engines powered a vast array of military equipment, including tanks, armored cars, scout cars, Jeeps and amphibious tractors, landing craft and trucks for all purposes.

After the war the company struggled to adapt to a changing market, and World War II remained its peak in terms of output, earnings, and profits.

April 18, 1955 - Railroad mechanical refrigerator cars - "Trane. A Hercules 52-hp 6-cylinder diesel engine drives a 25-kw 220-volt, 3-phase, 60-cycle generator. The condenser on the first PFE installation." (Railway Age, April 18, 1955) (This was likely a larger stationary installation, rather than a rail car.)

The latter half of the 20th century saw Hercules change hands multiple times. First, in 1961, to the Cleveland-based Hupp Corp., but Hercules failed to grow it substantially, shifting its focus back to military applications.

In 1967 White Motor Corporation,also based in Cleveland, bought Hupp and had ambitious expansion plans for Hercules, which became known as White Engine. The plant operated as the White Engine Division. During this period, around 85 percent of production was for military use, including multi-fuel engines for 2-1/2 and 5-ton trucks.

In 1976 the White Engine Division was sold as a separate entity, operating as White Engines, Inc., until 1987. Then in 1986 it was sold to Wedtech. In 1987 the division was sold again, to a group of investors who reinstated the proud name Hercules Engines, Inc. Even with its proud heritage, Hercules faced persistent financial struggles. By the 1990s, its cash flow was precarious, and military contracts began to dry up. The company finally ceased operations in 1999. At the time of its closure, its facility in Canton covered 26 acres and had over 600,000 square feet of industrial space.

International Harvester

International Harvester (IH) traces its roots to 1831, when Cyrus Hall McCormick demonstrated the first reaper. By 1846, demand in the Midwest led to large-scale production in Chicago. In 1902, McCormick merged with Deering Harvester and three smaller firms to form International Harvester, aiming to expand product lines and global markets.

As farming machinery evolved from horse-drawn to steam-powered, the internal combustion engine became a promising alternative. Deering had experimented with gas engines since 1889, producing nearly 50 stationary engines per day by 1902. IH naturally adopted internal combustion for its implements, tractors, and trucks, using kerosene engines by 1909.

IH began diesel research in 1916, developing a 10 hp single-cylinder horizontal pre-combustion diesel before 1919. Seeking better economy and torque, engineers studied European designs. In 1927, a four-cylinder Dorner diesel was tested, leading IH to build its own engine in 1928. However, it was abandoned in 1930 as unsatisfactory. Further testing of foreign engines led IH to focus on its own vertical pre-combustion chamber design, completed in early 1930, alongside a bypass-controlled injection pump—predecessor to pre-1940 pumps. The starting method (gasoline start, warm up, switch to diesel) was also established.

By late 1932, a four-cylinder engine passed tests, entering production in April 1933 as the PD-40 (4-3/4" x 6-1/4" cylinders), remaining unchanged for three years. A six-cylinder PD-80 followed in February 1936. From 1936–1940, IH expanded lab research with high-speed cameras, leading to the improved UD series. The pre-combustion chamber design was radically altered, reducing excess air without raising peak pressures, improving load control, brake mean effective pressure, and speed range. IH retained its poppet nozzles but used American-Bosch multi-plunger pumps with governors, emphasizing governed torque control—a pioneering feature.

In early 1941, IH released a new single-plunger injection pump for UD four-cylinder engines. After WWII, two new six-cylinder engines were developed: one based on the four-cylinder, and a larger 5-1/4" x 7" model. Key design priorities included easy starting, performance, low-cost fuel injection, combustion chamber design, pistons, and service reliability. The latest engine shared many parts with gasoline engines of the same size, reducing costs and speeding production.

In 1938, IH built its first tractor designed solely for industrial use (not a farm conversion). This led to the creation of an Industrial Power Division in 1944, separate from Farm Tractor Division. In 1945, IH purchased its current Melrose Park, Illinois plant to house industrial activities, alongside Milwaukee and Chicago tractor works.

During the 1950s, IH manufactured a series of small 4-cylinder gasoline engines, along with a series of 3-cylinder Diesel engines, both aimed specifically for industrial use. Other sources note that Santa Fe used IH engines in 1953 in its initial group of 30 cars as part of the company's earliest mechanical refrigerator cars. Research suggests that IH manufactured two models of 3-cylinder small Diesel engines, the D-155, with 155 cubic inches and 35-40 horsepower, and the larger D-179, with 170 cubic inches and 41-46 horsepower.

(More research is needed to determine the extent, if any, use of IH engines by other operators of mechanical refrigerator cars. Research finds that Pacific Fruit Express did not use IH engines, but Fruit Growers Express may have, as well as other companies with fewer than 500 cars.)

(Read the Wikipedia article about International Harvester)

(Read the FundingUniverse article about International Harvester, as part of Navistar)

Onan

Founded by David W. Onan in 1920, the D. W. Onan & Sons company initially focused on small power plants for rural homes before branching out into engine-driven generator sets. While Onan is best known for its generators, the company designed and produced its own air-cooled engines for a wide range of applications. In the late 1940s and early 1950s, Onan engines were sold to manufacturers of truck refrigeration units, making them a crucial component in the transport of perishable goods during that era.

(There is only very limited and brief mention about the Onan company furnishing engines for mechanical refrigerator cars, but the company history is interesting, none the less.)

(Read more about the D. W. Onan & Sons company)

Perkins

Perkins was a successful small engine design used in a limited number of mechanical refrigerator cars, in the form of limited test installations. The engines were built by the Perkins Engines Company Ltd. originally based in Pertersbough, England. The company was founded in 1932 to build small high-speed diesel engines, and today is owned by Caterpillar (since 1998).

Sheppard

(A Sheppard Diesel engine was used in the AT&SF test of mechanical refrigeration, in car number SFRD 12000, completed in May 1949. The car was converted back to ice-cooled in 1953. The test of the refrigeration equipment was successful, but the other features of the car such as insulation and controls, as well as the choice of the Diesel engine itself, required more design work. This was the only known application of a Sheppard diesel engine in railroad service.)

In 1935, R. H. Sheppard, after a decade of work with gasoline engines, turned his attention to small diesels. He set six clear goals: simple design for inexperienced operators; fuel versatility (from Bunker C to kerosene without adjustment); flexible performance across speeds; adaptability for marine, stationary, truck, tractor, and contractor use; all-American design using no foreign patents; and durability comparable to large, low-speed engines.

By late 1937, he had organized the R. H. Sheppard Company in Hanover, Pennsylvania, to produce his designs.

The first product was the Sheppard Model 6, a 3-cylinder, 4-inch bore, 5-inch stroke, four-cycle diesel originally rated 25 hp at 1,200 rpm, later upgraded to 30 hp at 1,800 rpm for continuous full load, with fuel consumption not exceeding 0.50 lb per hp·hour. It featured Sheppard-designed components: fuel pump, pre-combustion chamber, oil-cooled pistons, Silchrome valves and seats, and replaceable cadmium-silver steel-backed bearings.

In early 1941 came the single-cylinder Model 7 series (4-inch x 5-inch), rated 8 hp at 1,200 rpm, later 10 hp at 1,800 rpm. In early 1945, 4-1/4-inch bore models added 1 hp per cylinder.

The Model 13 series (early 1946) was a two-cylinder engine bridging the compactness of Model 7 with the power of Model 6A, delivering 20–22 continuous hp at 1,800 rpm.

By late 1946, Sheppard produced an air-cooled single-cylinder Model 14. Dimensions: 28-1/2-inches high, 20=3/4-inches wide, 22-1/2-inches long. This four-cycle engine developed 3.5 continuous hp at 1,800 rpm, with 28 cu. in. displacement, a 3.5% governor regulation, and both hand and 12-volt electric starting. Applications included railroad communications, shipboard lighting, pumps, compressors, and direct connection to 2-kW generators for battery charging (DC) or farm lighting circuits (AC).

Throughout, Sheppard emphasized "All American" design, patents, and production, no foreign patents. Engineers developed each part as an integral unit. All models are self-contained, requiring no added accessories, and most parts interchange across models. The Sheppard governor provides close regulation and allows two or more generator sets to run in parallel under constant or varying loads. The company holds numerous patents in small diesel development.

"The Sheppard air-cooled diesel is, we believe, the first commercially successful air-cooled diesel power-plant. One of these has been running 11,500 hr rated 5.4 hp at 2000 rpm without attention to valves, rings, bearings, or fuel pump. (Paper "Features of the Sheppard Diesel" was presented at SAE Annual Meeting, Detroit. Jan. 14, 1949)" (Society of Automotive Engineers Journal, Volume 57, Number 5, May 1949, page 70, 92)

"The R.H. Sheppard company built a line of farm tractors using their own diesel engine in the early 1950s in Pennsylvania. Sheppard manufactured diesel engines for a range of applications in the post-war period. In 1949, the Sheppard Diesel line of tractors was developed to utilize the diesel engines in farm tractors. Competition from the major tractor manufacturers, along with slow acceptance and cost of the diesel engine led Sheppard to stop tractor production in 1956 to focus on power steering equipment." (TractorSpecifications.com)

Witte

In 1953, Witte Engine Works diesel engines were highly sought after by railroad officials for use in mechanical refrigerator cars due to their extreme ruggedness and stamina.

The primary Witte models used for rail refrigeration were horizontally opposed two-cylinder engines, often pre-equipped from the factory with direct-connected generators:

• Witte Model 100: A twin-opposed cylinder engine rated at 19 horsepower.
• Witte Model 120: A more powerful twin-opposed cylinder version rated at 27 horsepower.

These units typically included automatic shutdown systems for low oil pressure or high water temperature to ensure reliability during long hauls.

Many refrigerator cars utilized Witte "Dieselectric" plants, which were compact, self-contained generator sets that could fit easily into the mechanical compartments of a refrigerator car.

During this year, major operators like Pacific Fruit Express (PFE) and Santa Fe (SFRD) were rapidly building or ordering new classes of mechanical reefers (such as PFE's Class R-70-7 and Santa Fe's Class Rr-54) as the ICC began permitting the discontinuance of traditional bunker icing.

From Railway Age, November 19, 1956.

Refrigeration Unit Suppliers

1954
"Four companies are principal suppliers of fruit car refrigerating equipment: Trane Company; Frigidaire Division of General Motors Corporation; Carrier Corporation and United States Thermo King Railway Corporation." ([Norfolk] Virginian-Pilot, July 30, 1954)

"In 1955 there were at least six different refrigeration systems in use for mechanical refrigeration of railroad refrigerator cars. In addition to these six systems which have already been developed to the point of use. York and International Harvester are working on this problem and will probably have refrigerator-car systems ready soon." (Railway Age, April 18, 1955)

"Production of a 50-ft mechanical refrigerator car based on a 40-ft prototype developed by the Electro-Motive Division of General Motors is now under way. The welded all-steel body is an envelope container mounted resiliency on the underframe. It may be lifted off as a unit. Insulation is structural plastic foam. Refrigeration is by Frigidaire. Doors are 8 ft wide." (Railway Age, April 18, 1955)

Carrier

"Carrier. The diesel-electric power plant is rated at 20 kw and weighs 2,000 lb. Two compressors are driven by 7-1/2-hp motors. The two compressor-motor combinations may be used singly or as two separate refrigeration systems. For light loads with only one compressor operating, approximately 60 per cent of full capacity can be attained. Electric heaters are used for automatic defrosting plus car heating. Refrigeration equipment totals 2,490 lb." (Railway Age, April 18, 1955)

Carrier Transicold's innovation included the first front-wall refrigeration unit for containers in 1968. The use of front-wall mounted refrigeration units began in the late 1990s.

(Read more about the Carrier Transicold refrigeration units)

Fairbanks-Morse

"Saylor-Beall, Dole, Fairbanks-Morse. This system employs cold plates to distribute the cooling effect instead of evaporators and fans. The cold plates constitute a refrigerating reservoir the temperature of which will rise at the rate of about 1 deg an hour after a failure. The Brunner compressor is rated at 5 hp. The system weighs 6,100 lb." (Yes, over 3 tons; not hard to see why this design was not adopted.) (Railway Age, April 18, 1955)

Frigidaire

The Frigidaire Corporation was organized in 1919 when the original company, the Guardian Frigerator Company, was purchased by General Motors and renamed. The predecessor Guardian Frigerator Company was incorporated on April 4, 1916, with Detroit as its headquarters. First located in Detroit, producing only 50 machines in its first year. After being sold to William C. Durant in 1918 and then to General Motors in 1919, the company was renamed Frigidaire Corporation. In 1920, operations were transferred to Delco-Light Company in Dayton, Ohio, where, with the help of inventor Charles F. Kettering, the product was re-engineered for mass production.

By 1926 Frigidaire was separated from Delco-Light. After the separation, the Frigidaire company went on to create innovations in metal cabinets, porcelain enamel, and commercial cooling equipment, as well as its emerging leadership in air conditioning. In 1932, the company began its efforts in the air conditioning of railroad passenger cars.

"Frigidaire. The power plant is a 34-hp Detroit two-cycle diesel engine directly connected to a Delco 20-kw, 3-phase, 220-volt, 60-cycle generator which operates continuously. There are two sealed compressors, each driven by a 5-hp motor. Two condensers are assembled in a single structure. The cooling unit has two evaporator sections, and one condensing unit is connected to each section." (Railway Age, April 18, 1955)

(Read more about the Frigidaire company)

Thermo King

Before the 1945–1960 period, the company—then known as U.S. Thermo Control—developed foundational refrigeration technologies that would later enable the designs used in railroad refrigerator cars. From 1938 to 1940, it created the "Model A," the world’s first successful mechanical transport refrigeration unit, a gasoline-powered, 2,200-pound system designed for trucks. In 1941, the lighter, more reliable, nose-mounted "Model C" was introduced, using the brand name "Thermo King." During World War II, the U.S. military extensively used the Model C to transport blood, medicine, and food, proving its ruggedness and reliability.

In the late 1940s, Thermo-King began its move into refrigeration units for railroad freight cars, building directly on its proven Model C refrigeration for trucks, which was adapted for rail transport in 1948. At the time, railroad cars still relied on manual ice loading for cooling, which caused rotting floors and cargo contamination, whereas Thermo-King’s gasoline-powered, onboard units offered a cleaner, more efficient, and more reliable solution. During this period, the company’s annual revenues reached approximately $3–4 million, it employed 200 people, and it opened a training school for mechanics, also in 1948.

In 1948 the Thermo King company furnished equipment for rail cars operated by Fruit Growers Express, the Canadian National and Western Fruit Express. To ensure dependable service each car had two 28 horsepower, three-ton capacity refrigeration units, with both units operating to precool the car, and when the desired temperature was reached, one unit shut down. It would then automatically start up if the other unit should fail for any reason. Gasoline for the car was carried in a 155 gallon tank. The fuel, maintenance and depreciation costs were figured at 27 cents an hour.

(Read more about the Thermo King refrigeration units)

The Trane Company

(Pacific Fruit Express used Trane refrigeration units in three class of their mechanical refrigerator cars. The first group, coupled to Detroit Diesel engines, was their R-70-7 class cars (11 cars built in 1952-1953 by SP in Roseville), numbered as PFE 300015-300025. The second group, coupled to Witte Diesel engines, was their R-40-30 class cars (300 cars built in 1958 by SP in Los Angeles), numbered as PFE 100028-100327). And the third group, also coupled to Detroit Diesel engines, was their R-70-12 class cars (989 cars built in 1960 by SP in Los Angeles), numbered as PFE 301213-302201.)

(Santa Fe used Trane refrigeration units in a very large number of their refrigerator cars. The Trane equipment was coupled to several brands of diesel engines. Most were connected to Detroit Diesel engines, but the early tests and small groups were driven by Fairbanks-Morse and Sheppard engines. The Detroit Diesel engines were purchased direct from General Motors in the 1950s, but in the 1960s the Detroit Diesel engines were purchased as complete power units from Stewart & Stevenson in Texas, and in the 1970s from Western Branch Diesel based in Portsmouth, Virginia, and has since expanded to several other East Coast states. Stewart & Stevenson was originally based in Houston, Texas, and has since expanded worldwide.)

By the time the Trane company became involved in the mechanical refrigeration of railroad freight cars, it was already well established in the air conditioning of railroad passenger cars. The Trane company became involved with railroad passenger car air conditioning (refrigeration/cooling) in the early 1930s, coinciding with the broader industry introduction of rail passenger car air conditioning.

The Trane Company's factory was in La Crosse, Wisconsin.

(Read more about the Trane Company and its involvement in railroad mechanical refrigeration)

Waukesha

Founded in 1906 in Waukesha, Wisconsin, the Waukesha Engine Company began by manufacturing hand-built gasoline engines for local boat builders. It quickly expanded into truck, farm tractor, and industrial markets. By 1912, its engines powered Ingersoll-Rand's first portable air compressor, replacing steam engines in hoists, excavators, and pumps. During World War I, Waukesha focused on farm tractor engines, producing for over thirty builders. In 1917, company co-founder Harry L. Horning led the U.S. Army’s design of its first standard engine for military trucks, with Waukesha delivering the first unit in just eleven days.

After World War I, the company targeted logging and oil drilling, helping these two industries transition from steam power to gasoline power. When the 1920s brought new fuel challenges due to oil refining changes, Waukesha invested heavily in laboratory research. By 1924, it introduced the Waukesha-Ricardo cylinder head, which reduced engine knock through controlled turbulence.

In 1926, Waukesha began diesel engine research, establishing better ways to burn fuel by 1929. In 1931, it launched the Waukesha-Hesselman oil engine, a low-compression, spark-ignition engine using fuel oil, popular for logging and excavating.

In 1935, Waukesha introduced the first engine-driven railroad passenger car air conditioning and lighting generators running on bottled propane gas. Two years later, it produced the first direct-drive engine units for highway bus air conditioning and truck/trailer refrigeration. Development continued vigorously into the 1940s, including special testing for military applications. Through decades of innovation, Waukesha established itself as a pioneer in both gasoline and diesel engine technology, fuel research, and testing standards.

The Waukesha Motor company attempted to build a diesel engine for refrigerator car service in 1954-1955, to match its successful propane-fueled Engineator used in the air conditioning units of railroad passenger cars. But the design did not make it through the company's internal testing and the effort stopped.

July 30, 1954
"Waukesha Motor Company, Waukesha, Wis., says that within 60 days it will introduce a new gasoline motor that will simplify the design of mechanical refrigeration units, and will sell for roughly one-third less than current makes. Company spokesmen also claim the equipment will be easier and cheaper to maintain, aiming to reduce the barrier of entry." ([Norfolk] Virginian-Pilot, July 30, 1954)

"Waukesha. A 42-hp 6-cylinder diesel engine, directly connected to a 20-kw, 220-volt, 3-phase, 60-cycle generator, is mounted under the car. There are either one or two air-conditioning packages. Each contains a compressor, condenser, evaporator, motors and fans. Each is mounted in a bunker hatch with the cold section down in the bunker and the hot section above the hatch. The power unit weighs 2,100 lb." (Railway Age, April 18, 1955)

Quoting the Waukesha ad in Railway Age, April 18, 1955.

(Unlike the very successful Waukesha "Engineator" for railroad passenger cars, this new Waukesha unit for freight cars, branded as the "Diesel-Icer," would be, as mentioned, diesel-fueled, a version of the propane-fueled Engineator. Quoting the Waukesha County Freeman newspaper, February 18, 2014, "In 1955, the company introduced the “Diesel-Icer” which was to be used to refrigerate box cars. The company equipped a car at its plant, and was the first to do so, but because of competition with Ford and Westinghouse, Waukesha’s unit never caught on. The refrigeration arm of the company was re-purposed in 1956 and named the Special Products Division. It concentrated on stationary power units." Ads show that the car tested was Fruit Growers Express FHIX 41127.)

(Waukesha advertised its Diesel-Icer in Railway Age magazine from May 1955 through May 1956.)

Early Attempts

From the Smithsonian

Sturtevant

The B. F. Sturtevant company, Boston, Massachusetts, furnished the fans used in railway car air conditioning. These fans were used to blow air across bins of ice stored on railway cars in the earliest versions of air conditioning. Known as "Ice activated" systems, this type of air conditioning began to be replaced in the high priority and premier trains when the later steam injector system was developed.

(Read more about ice activated and steam injector air conditioning)

"Henry L. Galson's career as an engineer who played a key role in the development of self-contained air-conditioning equipment is traced. He was a co-recipient of the City of Philadelphia's John Scott Medal for the development of the De la Vergne air-conditioning apparatus (1933), the first self-contained, hermetic, air-cooled room air conditioner with a reverse cycle. Galson's basic patents for the De la Vergne unit were purchased by five companies (GE, Westinghouse, Frigidaire, Carrier and Sturtevant). His application of the packaged heat pump to room and railway car air conditioning was visionary." (International Institute of Refrigeration)

"It was also in 1910 that Sturtevant took out its first patent for railway car cooling. On this foundation Sturtevant has built up through the years a patent background that covers nearly all of the moving vehicle field, including railway coaches of all types and sleeping cars. Since the air conditioning of railway cars began to go forward about 1930, Sturtevant has supplied the equipment for nearly 8000 cars of all types in this country and Canada." (Charlotte Observer, May 15, 1938)

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