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Mary WALTON and the reduction of pollution from trains in New York

Mary WALTON is a pioneer in environmental ecology in the 19th century!  Her inventions reduced pollution from trains in New York and made her a wealthy woman who collected patent royalties for the rest of her life.

Of Mary Walton’s youth and education, almost nothing is known except for a statement made in 1884:

“My father had no sons and believed in the education of his daughters. He spared no pains or expense for this purpose.” Mary WALTON, 1884

Yet there is no record of her having received a formal education. But as we shall see, she was hailed years later by Woman’s Journal as a woman who had succeeded where the best-known inventors of the century had looked at the subject without being able to provide a solution.

What subjects did Mary Walton use her brilliant brain on?

On very concrete problems of her time. As the owner of a boarding house in New York City, right next to the city’s new Gilbert Elevated Railroad, she was bothered by the noise, or rather the constant roar of the steam engines, the sound of screeching brakes, the vibrations that shook the adjacent buildings, and the smoke that escaped to leave a layer of soot on every surface. So she set out to reinvent the railroad technology of the day and succeeded, where Thomas Edison himself had failed.


Let’s review the context of the time. The American Industrial Revolution drew middle-class workers from rural farms to factory jobs that were springing up at a dizzying pace in cities like New York, where they were soon joined by millions of European immigrants seeking a new life.  All these people were transported around New York City by a new system of elevated trains, or “els,” that echoed, puffed, and belched smoke along nine miles of track that ran along most of the city’s major thoroughfares. 

The songs and chants that had long marked the rhythm of manual labor were soon drowned out by the incessant clanking, humming, and buzzing of the state-of-the-art machines that powered the city’s factories. And the air New Yorkers breathed was polluted by these machines, and by many other sources of pollution: oil and kerosene refineries, varnish and fertilizer factories, ammonia plants… that sent thick fumes over the city.


A pioneer in factory pollution control, Walton, as early as 1879, developed a method of directing the fumes emitted from locomotive stacks (but applicable equally to industrial and residential stacks) into water tanks, where the pollutants were retained and discharged “into the sewers, or other suitable channels for conducting them to a distant or desired locality”. This water tank system redirected the smoke, odors, and pollutants away from the city and out of the air. The method is listed under U.S. Patent #221,880.

 Traveling to England to promote his invention, British officials hailed his device as “one of the greatest inventions of the age.” Perhaps not surprising, given Charles Dickens’ 1852 description of London’s fogs and “streets full of dense brown smoke.”

Noise pollution still needs to be addressed: The elevated trains created an intolerable amount of clatter and bells and disturbed daily life considerably. It was so disruptive that people couldn’t stand living near the tracks. New York City even enlisted the help of America’s most famous inventors, including Thomas Edison, to find a solution. However, it wasn’t Thomas Edison, who worked on it for 6 months, who was able to solve the problem. It was Mary Walton, and her approach deserves to be known.

She began by walking the city’s elevated tracks for three days, hiding on the back platform to listen, observe, with her head bent toward the tracks. After those three days, Walton discovered that the rails amplified the noise of the train because of the simple wooden supports running through them. She then set about building a prototype model railroad in her basement. She experimented with different noise reduction systems, and developed a soundproofing device consisting of a wooden box, painted with tar to withstand the elements, lined with cotton and filled with sand to absorb the vibrations, and thus attenuate the noise. Her idea to use sand was inspired by the use of sand to dampen the noise of anvils near her home.

 A full-scale version of Walton’s device was then built; after a series of tests Walton was granted U.S. Patent No. 327,422 on February 8, 1881.

When her idea for a railroad was patented, her son recommended that she does it in his name (his own), so as not to be seen as a “strong-minded woman”. The mother’s response was tasty: “Make your own inventions, son,” she replied, “and have them put your name on them! She sold the rights to the Metropolitan Railroad of Innovative York City for $10,000 and royalties for life. The system was quickly adopted by other elevated railroads, which prospered under Walton’s new environmentally friendly system, making her a wealthy, well-known woman.

By the 1930s, almost all elevated railroads would be phased out and replaced by underground rails.  However, there are still elevated railroads in Chicago, and they use Walton’s patented noise reduction technology. 

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Written by Emmanuelle P.

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