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Interpreting the Evidence

Air Conditioning a Pullman Car

  • Documents in this Activity:
  • Historical Eras:

    The Great Depression and WW II (1929 - 1945)

  • Thinking Skill:

    Historical Analysis & Interpretation

  • Grade Level:

    Lower Elementary
    Upper Elementary
    Middle School
    High School
    College University

  • Topics:


  • Primary Source Types:


  • Regions:

    New York State

  • Creator:

    NYS Archives Partnership Trust Education Team

  1. Load Air Conditioning of Pullman Car, 1936 in Main Image Viewer

Suggested Teaching Instructions

Document Description
Packing the bottom of a train's Pullman Car with ice to keep travelers cool, 1936.
Historical Context
Prior to the 1860s, the shipping of perishable foods was limited due to poor food preservation technology. However, with the introduction of refrigerated rail cars, known as reefers, produce and meat could be safely shipped longer distances. J.B. Sutherland patented the refrigerated railroad car in Detroit, Michigan in 1867. As the reefers became more sophisticated, meat and produce could be shipped over even greater distances.

The reefer spurred the boom of the natural ice industry.  The demand for shipping ice, drinking ice, and ice for household use increased. As more companies entered the ice harvesting market, the price of ice decreased, making ice a practical refrigerant and commodity. The year 1886 was a peak year for natural ice harvesting. In the United States, 25 million tons were harvested. At 2,000 pounds a ton, that is 50 billion pounds!

Reefers were kept refrigerated by inserting insulation between an inner and outer wood sheathing. Natural materials, such as horsehair or sawdust, were used as the insulation. In the front and rear of the reefer were ice bunkers. These were lined with metal and filled with ice. On the floor of the reefer was ice sprinkled with salt, which kept the ice colder. The cool air emitted from the ice bunkers and floor was circulated around the reefer by window fans. The window fans maximized coolness by continually circulating the air over the ice.

However, the reefer was not completely flawless. Maintaining the proper temperature was hard work. Lack of properly distributed insulation and ice would destroy some products by freezing them and others by not keeping them cool. Additional ice had to be loaded daily into the ice bunkers to replace the melted ice. But, if the perishable goods were delivered to their destination unspoiled, the rail car owner would make a considerable profit.

The ice industry and the railroads shipped Georgia peaches, California grapes, Washington apples, and Florida citrus fruits all over the country. German lager beer, Chicago meats, seafood, milk, butter, and cheese were also distributed across the nation using reefers.
Unfortunately, the use of natural ice eventually became a health problem. By 1890, clean waterways became increasingly harder to find due to pollution and sewage dumping. The brewing, meat packing, and the dairy industries all complained of product contamination by polluted ice. These accusations led to the development of new technology, including mechanically manufactured ice and mechanical refrigeration. The General Electric Company was the first to answer this demand in 1911 with the first electric icebox, which used ammonia, now a known toxic substance, as the cooling agent.

Unlike the industries, domestic refrigeration relied on naturally harvested ice until well into the 1920s. During this time, an ice wagon would deliver ice cakes from the icehouses or railroad yards to homes and businesses in urban areas. Typically, a business or homeowner would hang a sign in a window indicating the amount, in pounds, of ice that was needed. Some of the signs would indicate up to 300 pounds! Children would often change these signs on the sly, to possibly chance upon some extra ice.  However, the affordability, practicality, and convenience of the new system of mechanical refrigeration eventually rendered iceboxes obsolete. By the mid-1920s, mechanical refrigerators were being produced by the thousands, and by the 1930s, the millions.
Essential Question
How does geography impact local economies?
Check for Understanding
Describe the scene in the photograph and evaluate the impact of geography on industry.
Historical Challenges
Research the history of refrigeration. What were some early ways people kept food cool? Make a timeline showing historical advances in refrigeration.
Interdisciplinary Connections
Math: If a gallon of ice weighs about 7.5 pounds, about how many gallons of ice were harvested in the United States in 1886?
Science: Why is it important to refrigerate food? Draw a diagram showing how a modern refrigerator works