Technology and the “Conroe Crater”

Texas well disaster of 1933 helped bring advancements in directional drilling.

 

A Depression-era disaster in a giant oilfield near Conroe, Texas, brought together the inventor of portable drilling rigs and the father of directional drilling. George E. Failing and H. John Eastman employed new technologies that allowed “the bit burrowing into the ground at strange angles.”

Early Conroe oil wells revealed shallow but “gas charged” oil-producing sands in what would prove to be the third-largest oilfield in the United States at the time. By the end of 1932, more than 65,000 barrels of oil flowed daily from 60 wells in the region north of Houston. (more…)

Discovering Los Angeles Oilfields

Natural oil seeps, giant oilfields, and the beginning of the California petroleum industry.

 

“Everyone thinks of Los Angeles as the ultimate car city, but the city’s relationship with petroleum products is far more significant than just consumption.” — Center for Land Use Interpretation

When struggling prospector Edward L. Doheny and his mining partner Charles Canfield decided to dig a well in 1892, they chose a site already known for its “tar” pools that bubbled to the surface. (more…)

First Oil Tank Car

Densmore brothers advanced oil industry infrastructure — and helped create “QWERTY” typewriter keyboard.

 

As Northwestern Pennsylvania oil production skyrocketed following the Civil War, railroad oil tank cars fabricated by two brothers improved shipment volumes from oilfields to kerosene refineries. The tank car designed by James and Amos Densmore would not last, but more success followed when Amos invented a new keyboard arrangement for typewriters.

Flatbed railroad cars with two wooden oil tank cars became the latest advancement in oilfield infrastructure after the Densmore brothers patented their design on April 10, 1866.

The inventors from Meadville, Pennsylvania, had developed an “Improved Car for Transporting Petroleum” one year earlier in America’s booming oil regions. The first U.S. oil well had been drilled just seven years earlier along Oil Creek in Titusville.

Densmore brothers circa 1860s wooden oil tank car exhibit in Pennsylvania.

The first practical petroleum railway tank car was invented in 1865 by James and Amos Densmore at the Miller Farm along Oil Creek, Titusville, Pennsylvania. Photo courtesy Drake Well Museum.

Using an Atlantic & Great Western Railroad flatcar, the brothers secured two tanks to ship oil in bulk. The patent (no. 53,794) described and illustrated the railroad car’s design.

The nature of our invention consists in combining two large, light tanks of iron or wood or other material with the platform of a common railway flat freight-car, making them practically part of the car, so as they carry the desired substance in bulk instead of in barrels, casks, or other vessels or packages, as is now universally done on railway cars.

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Development of railroad tank cars came when traditional designs, including the flatcar, hopper, and boxcar, proved inadequate for large amounts of oil — often shipped in 42-gallon barrels.

New designs were born out of necessity, as the fledgling oil industry demanded a better car for the movement of its product, according to American-Rails.com.

“Before the car was developed, railroads used a combination of boxcars, flatcars, and gondolas to haul everything from lumber and coal to crude oil, molasses, and water (by use of barrels),” noted Adam Burns in 2022. “One of the most prolific car types you will find moving within a freight train today is the tank car.”

A Densmore two-tank oil tank car is being filled among oil derricks.

Prone to leaks and top heavy, Densmore tank cars provided a vital service, if only for a few years before single, horizontal tanks replaced them.

According to transportation historian John White Jr., the Densmore brothers’ oil tank design essentially consisted of a flat car with wooden vats attached. “The Central Pacific is known to have used such specialized cars to transport water, he noted in his 1995 book, The American Railroad Freight Car.

“However, prior to the discovery of oil by Colonel Edward (sic) Drake near Titusville, Pennsylvania, on August 27, 1859, the tank car was virtually non-existent,” added White, a former curator of Transportation at the Smithsonian Institution.

Dual Tank Design

The brothers further described the use of special bolts at the top and bottom of their tanks to act as braces and “to prevent any shock or jar to the tank from the swaying of the car while in motion.”

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A Pennsylvania Historical Commission marker on U.S. 8 south of Titusville commemorates the Densmore brothers’ significant contribution to petroleum transportation technology. Dedicated in 2004, the marker notes:

The first functional railway oil tank car was invented and constructed in 1865 by James and Amos Densmore at nearby Miller Farm along Oil Creek. It consisted of two wooden tanks placed on a flat railway car; each tank held 40-45 barrels of oil. A successful test shipment was sent in September 1865 to New York City. By 1866, hundreds of tank cars were in use. The Densmore Tank Car revolutionized the bulk transportation of crude oil to market.

The benefit of such railroad cars to the early petroleum industry’s infrastructure was immense, especially as more Americans eagerly sought oil-refined kerosene for lamps.

Despite design limitations that would prove difficult to overcome, independent producers took advantage of the opportunity to transport large amounts of petroleum. Other transportation methods required teamsters hauling barrels to barges on Oil Creek and the Allegheny River to get to kerosene refineries in Pittsburgh.

Abandoned Densmore oil tank cars among derricks with improved horizontal tanks nearby.

Riveted cylindrical iron tank cars replaced the Densmore brothers’ dual wooden tanks — seen here discarded. Photo courtesy Drake Well Museum.

As larger refineries were constructed, it was found that it cost $170 less to ship 80 barrels of oil from Titusville to New York in a tank car instead of individual barrels. But the Densmore cars had flaws, notes the Pennsylvania Historical Commission.

They were unstable, top heavy, prone to leaks, and limited in capacity by the eight-foot width of the flatcar. Within a year, oil haulers shifted from the Densmore vertical vats to larger, horizontal riveted iron cylindrical tanks, which also demonstrated greater structural integrity during derailments or collisions.

The same basic cylindrical design for transporting petroleum can be seen as modern railroads load products from corn syrup to chemicals — all in a versatile tank car that got its start in the Pennsylvania oil industry.

The largest tank car ever placed into regular service was Union Tank Car Company’s UTLX 83699, rated at 50,000 gallons in 1963 and used for more than 20 years. A 1965 experimental car built by General American Transportation, the 60,000-gallon “Whale Belly,” GATX 96500, is now on display at the National Museum of Transportation in Saint Louis. 

1863 Tank Car Patents

Although not manufactured, other inventors came up with new ways for transporting oil from booming oilfields. John Scott of Lawrenceville, Pennsylvania, on January 20, 1863, patented (No. 37,461) a rectangular design for his “car for carrying petroleum, etc.”

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John Clark of Canandaigua, New York, on November 3, 1863, was awarded a patent (No. 40,458) for another “improvement in cars for carrying petroleum.” His design put a long and flat sheet-metal tank under an ordinary freight car.

Finally, a “Petroleum Car” design with a cylindrical shape similar to modern railroad tank cars was patented (No. 38,765) on June 2, 1863, by Samuel J. Seely of Bookland, New York. The Seely patent might be the first design for a petroleum car shaped like those in use today.

Oil Tanks to Typewriters

Although the Densmore brothers left the oil region by 1867 — their inventiveness was far from over. In 1875, Amos Densmore assisted Christopher Sholes in rearranging the “type writing machine” keyboard so that commonly used letters no longer collided and got stuck. The “QWERTY” arrangement vastly improved Shole’s original 1868 invention.

Densmore typewriter company advertisement.

Amos Densmore helped invent one of the first practical typewriters.

Following his brother’s work with Sholes, inventor of the first practical typewriter, James Densmore’s oilfield financial success helped the brothers establish the Densmore Typewriter Company, which produced its first model in 1891. Few historians have made the oil patch to typewriter keyboard connection — including Densmore biographers.

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The Pennsylvania Historical Commission reported that biographies of the Densmore brothers — and their personal papers at the Milwaukee Public Museum — all refer to their innovative typewriters, “but make no mention of their pioneering accomplishment in railroad tank car design.” 

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Recommended Reading:  The American Railroad Freight Car (1995); Early Days of Oil: A Pictorial History of the Beginnings of the Industry in Pennsylvania (2000); Story of the Typewriter, 1873-1923 (2019); Myth, Legend, Reality: Edwin Laurentine Drake and the Early Oil Industry (2009). Your Amazon purchase benefits the American Oil & Gas Historical Society. As an Amazon Associate, AOGHS earns a commission from qualifying purchases.

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The American Oil & Gas Historical Society (AOGHS) preserves U.S. petroleum history. Please become an AOGHS annual supporter and help maintain this energy education website and expand historical research. For more information, contact bawells@aoghs.org. © 2025 Bruce A. Wells. All rights reserved.

Citation Information – Article Title: “Densmore Oil Tank Cars.” Authors: B.A. Wells and K.L. Wells. Website Name: American Oil & Gas Historical Society. URL: https://aoghs.org/transportation/densmore-oil-tank-car. Last Updated: July 14, 2025. Original Published Date: April 7, 2013.

Anadarko Basin in Depth

Giant Oklahoma rigs drilled to record depths in the 1970s.

 

The Anadarko Basin, extending more than 50,000 square miles across west-central Oklahoma and the Texas Panhandle, includes some of the most prolific U.S. natural gas reserves — and a 1974 drilling record.

Beginning in the late 1950s, when technological advances allowed it, Anadarko Basin wells in Oklahoma began to be drilled more than two miles deep in search of natural gas. Dangerous, highly pressurized formations required state-of-the-art blowout preventers (see Ending Oil Gushers — BOP). (more…)

Edwin Drake and his Oil Well

Biography of father of U.S. oil industry reaches total depth.

 

In August 1859, the man who would launch America’s petroleum industry was down to his last pennies — and a letter was on its way to “Colonel” Edwin L. Drake telling him to cease drilling at Titusville, Pennsylvania. Investors in the first oil company wanted him wanted out.

“As far as the company was concerned, the project was finished,” notes historian William Brice, PhD, in his 2009 biography of Drake, a former railroad conductor. “Fortunately that letter was not delivered until after they found oil.” (more…)

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