Almost on the Right Track: The Densmore Tank Car

The successful drilling for petroleum in northwestern Pennsyl­vania exploded a speculative excitement on a national level not seen since the California Gold Rush a decade earlier. “Colonel” Edwin L. Drake’s modest well at Titusville stirred an oil fever that attracted shrewd fortune seekers, sharp traders and adventurers from all areas of the country. They began to assemble not long after Drake’s well first began spew­ing liquid black gold on August 27, 1859. Just as John A. Sutter watched his remote ranch near the American River transformed into a bedlam of gold seekers, so too did resi­dents along Oil Creek witness a dramatic transformation of their sleepy farm lands in Venango County.

Pastoral villages became boom towns. Instant new com­munities, such as Pithole, sprang up over night in places inhabited months before only by the hare and the fox. Farm­land fetching no more than four dollars an acre began to command $500, $1,000 and, for choice locations, $7,000 an acre. The two hundred acre Holmden farm near Pithole sold for an unprecedented­ – and staggering – 1.3 million dollars in 1865! It was soon pierced by 100 wells and numerous oil storage tanks. Trees and vegetation disap­peared as greasy, malodorous, black crude coated the once sylvan countryside. Even a modest well could produce $150 a day, which was impressive in the era of the one dollar a day wage. A real gusher might produce 4,000 barrels a day, creating a sudden million­aire, but there were many dry holes and great fortunes were lost as well as made.

Known since ancient times, petroleum was used for elixirs, curatives and, occasionally, for building purposes. The supply was limited to what could be easily skimmed from streams and ponds as small quantities oozed up to the water’s sur­face. Only after Drake proved that it could be extracted in large quantities was petroleum seen as something more than a novelty. Scientists quickly demonstrated that it could be distilled to produce prodigious volumes of lubricating and illuminating oils. Industrial America had outgrown natural oils such as lard, tallow, rape seed and that rendered from whales. The potential supply of coal oil was nearly limitless, but production costs were sub­stantial and the market of 1860 could hardly afford one dollar a gallon. Kerosene, cheap lamp oil, was to become the everyday standard and nucleus of many fortunes, including tycoon John D. Rockefeller’s. During the first year – actually only about five months – Drake produced two thousand barrels, each con­taining forty-two gallons. In 1860, more wells were sunk and production reached 500,000 barrels. In the next year 2,113,609 barrels were produced, and by 1880 the wells in the Titusville region were pumping 26,000,000 bar­rels. Soon, large oil fields else­where in the nation and the world began to challenge the northwestern Pennsylvania wells. Gradually, northwestern Pennsylvania lost its standing as the world’s premier pro­ducer, but even today limited petroleum production con­tinues in these pioneer fields.

Production of crude oil swelled from a trickle to a del­uge in just a few years, and oilmen faced terrible logistical problems. What to do with this sea of oil suddenly brought to the surface became a terrible problem: how to efficiently store, refine and move it to market was the primary dilemma.

Soon every available tank and barrel was overflowing. Open ponds were a last resort and oil was poured into creeks when even these crude storage reservoirs were filled. Tank farms soon dotted Venango County’s hay and corn fields, but shipping crude to refineries in Pittsburgh, Cleveland and New Jersey loomed the major problem.

Before the oil boom, the Titusville area was a backward agricultural area and as such had little in the way of a trans­portation system. The region offered neither canals nor rail­roads, but depended on rural roads and shallow streams. Teamsters – three thousand of which were at work by 1865 – at first enjoyed unbridled pros­perity by hauling wagonloads of barreled oil to the nearest railheads. The teamsters bru­tally treated their horses and many died after a few months of strenuous service. Every available horse within a radius of thirty miles had been pur­chased and new animals had to be imported from greater distances. Roads became a litter of cast-off barrels, broken-down wagons and dead horses. Teamsters, also wanting to become rich, hiked their rates and soon demanded four dollars a barrel. Some of these men earned twenty to thirty dollars a week – then considered a fabulous income for a working man. Flat boats offered an alternative for oil shipped to Pittsburgh, but they were no more economical than the teamsters, especially because their movement was inhibited by low water. Collisions, floods and unexplained sinkings also made flatboats an unreliable means of transit. Yet by these costly and uncertain means, oil was reaching nearby railroads at Corry and other depots in the area.

The Pennsylvania and Ohio Railroad reported hauling 27,546 barrels of oil between December 1860 and February 1861. The Philadelphia and Erie Railroad, a new line much in need of revenue, realized $200,000 during 1861 from the oil trade. The obvious need for a direct rail line into the oil fields prompted construction of the Oil Creek Railroad which opened to Titusville in October 1862. This broad gauge line, through its connection, reached Cleveland and New York in November 1863. By early the next year, it extended to Oil City.

A direct rail connection did not solve the transportation problem. The teamsters’ monopoly was broken, and cheaper, faster service between the tank farms and distilleries was assured, but all shipments continued via the established barrel system.

Barrels could be loaded into ordinary railroad cars, and flat, box, gondola and even cattle cars were pressed into service. Railroads required shippers to use existing standard cars because they were readily available and could also be used for return loads. But barrels were expensive, rarely costing less than three dollars each. They were often scarce and liable to damage, loss and theft. They usually leaked one-tenth of their contents and sometimes as much as a third and efforts to seal their interiors with glue, molasses and glycerin were generally fruitless.

James and Amos Densmore were among the many oil men who pondered the problem of oil transport. They arrived in Meadville in 1861 to join the oil rush. They seem to fit a description of most oil region newcomers as rough looking, eager men bent on making money by sheer boldness and luck. James was born in Moscow, New York, in 1820 and spent most of his early years as a newspaperman in Wisconsin. Amos, a younger brother, was born in Rochester five years later. Neither had been particularly successful before entering the oil trade but they prospered in the new business and formally organized the Densmore Oil Company on July 18, 1863. James, the dominant partner, was described by a former business associate:

“A great ponderous, beefy-looking man of nearly three hundred pounds weight, with a florid complexion, a great shock of red hair, a shaggy beard, the eye of a hypnotist and the heavy jaw and animal force of a great Hyrcanian bull in Quo Vadis … restless as a tiger, a born bully with a fierce military spirit … he had an unfortunate personality that repelled many people instead of attracting them …. ”

Today, the sketch might be dismissed by historians as a burlesque exaggeration, but the Densmore Papers housed at the Milwaukee Public Museum confirm that James Densmore was a hard driving, determined individual given to an eccentric nature. A rather flattering biographical article in the National Cyclopedia of American Biography specifically notes his “bull-dog pertinacity” and “grim courage.” Of Amos almost nothing recorded in the way of personal traits exists, but one suspects he was comparatively mild-mannered, being so overwhelmed by his domineering, strong-willed brother.

The Densmores scrutinized the industry’s urgent need for the bulk hauling of oil, particularly because continued shipment by barrels meant continuing losses. Oil had already been bulk shipped in open barges but the absence of a good waterway was severely limiting. Pipeline experiments were underway, but even when perfected this means of liquid transit would not be available for many years. What was needed – and as soon as possible – was a special form of rail car for the transportation of large quantities of petroleum.

Correctly isolating the problem was the easy part of the question. Efficiently solving the problem was more difficult. At least half a dozen would-be inventors had, like the Densmores, already recognized the problem. Late in 1862, an unknown Canadian inventor made a test run of an iron tank car over the Grand Trunk Railway to Portland, Maine, from where the oil was shipped to England. Regrettably, no description of this pioneer vehicle is known to survive.

John Scott of Lawrenceville, Pennsylvania, received the first U.S. patent for a tank car in 1863. Scott proposed a box- like wooden tank lined with soldered tin plate sheets and partitions to limit surging of the liquids in transit. There is no record that Scott’s plan was tested. later that year, John Clark of Canandaigua, New York, obtained a patent showing a variation of Scott’s idea: a low rectangular tank looking much like a covered gondola car divided into eight compartments. A far superior plan was patented June 2, 1863, by Samuel J. Seely of Brooklyn, a designer of railroad cars who already held several patents. His idea for a tank car was advanced because he called for a horizontal iron tank that inevitably led to the modern car. His patent drawing shows a relatively short, large diameter tank fabricated from corrugated sheet iron.

There was a lull among tank car inventors for more than a year. On January 10, 1865, Joel F. Keeler, Pittsburgh, was granted U.S. Patent 45,834. Like Seely, Keeler was on the right track, although not the same track as his Brooklyn-based competitor. Keeler wanted an iron tank car, but he envisioned it as a combination tank and boxcar. He attempted to resolve the long-standing deficiency of single purpose bulk carriers by devising a car capable of serving more than one purpose. Very simply, he would mount a boxcar body on top of a half-round or U-shaped tank.

Keeler’s tank, made of 3/8 inch-thick iron, doubled as the car’s frame. The combination of frame and cargo vessel may be the earliest instance of modern unit construction in the railroad freight car field. Keeler ingeniously designed the trough-like tank-under-frame in three parts. The large central tank hung low to the rails, increasing capacity and lowering the center of gravity, while the two end tanks were made smaller to clear the wheels. A test car, fabricated at Pittsburgh’s Wallace Boiler Works in October, measured twenty-eight feet long and eight feet wide. The possum belly tanks held eighty barrels of oil. The box body would allow a return payload. For all its merits, Keeler’s idea was allowed to die.

At about the same time Keeler’s patent was issued, another scheme was afloat in the oil regions for a new style tank car. The Howard Oil Tank Car was a combination vehicle like Keeler’s plan but there all similarities ceased. Howard called for two giant drums, the ends of which had flanged tires so that the cylinders were both the cargo compartment and the wheels of the car. A frame and overhead platform held the drum wheels together and offered an open space for additional cargo. It is difficult to imagine a more impractical or foolish scheme; cargo, be it oil, grain or coal, would be incessantly tumbled and agi­tated during shipment. Assuming the cargo survived its rolling journey, the next wonder would involve the condition of the track after the passage of so much unsprung weight.

The scheme proffered by the Howard Company was actually an old idea patented nearly fifteen years earlier by Lawrence Myers of Philadel­phia. Myers envisioned cylin­der cars for grain or coal while Howard sought to apply them to the oil trade. At least one test car was constructed and the Pennsylvania Railroad agreed to acquire twenty-five cars from Howard in Septem­ber 1865. Perhaps this mis­guided contract was later can­celled for there was Little hope for success, nor is there any record of the operation of Howard cars.

While Howard’s folly was being pursued, a more practi­cal idea was patented by H.J. Lambaert on September 12, 1865, suggesting a simple con­tainer arrangement in which boxes about the size of an ordi­nary wagon bed would carry six to eight barrels. The box containers, loaded with filled barrels, were taken by wagon from the wellhead to the nearest rail siding. The boxes were then pushed onto waiting rail cars and carried to a refinery. The empty barrels could be returned to the oil fields in the same way, but the great defect of this idea was the continued dependence on barrels.

Many inventors were already grappling with the problem of bulk oil shipping before the Densmores became involved. Whether they were aware of their predecessors and contemporaries is uncer­tain, but considering the Densmores’ on-going involve­ments with the typewriter, inventors and patent office procedures, it is likely they had some idea about the patents issued. James and Amos Densmore, active in the oil trade, must have known that others were interested in resolving the crucial need for a practical tank car.

The Densmore brothers simply chose vertical tanks mounted on a flat car, an obvious idea but one which remained unprotected by a patent. It may be likely that the invention of the Densmore car was no more scientific than chance inspiration. Victorian era streets abounded with sprinkler trucks to wet down the dust swirled about by wagon traffic. Large wooden tanks had been used for centuries to store wine, vinegar, fats and other common liquids. Older style fire engines used wooden tubs as water reservoirs: Even the army watered troops and horses from tank wagons. But the most probable inspiration for the Densmores came from the tank farms they walked through each day. How much imagination did it take to mentally place one or two of the smaller tanks on a flat car? Obvious, of course, but apparently the Densmores were the first to seize upon such a transparent idea!

Assembling a car on the Densmores’ plan could not have posed much of a problem since it was merely a combination of existing parts. Their first two cars were ready for a test on or about September 1, 1865. Two tanks made of clear pine with close-fitting lids, both containing about thirty-five hundred gallons of oil, were positioned at the ends of a common flat car. The center of the car was vacant. Iron rods bolted through wooden beams crossed over the top of the vats held the big tubs to the car’s platform.

The first trip over the broad gauge Erie was monitored carefully and the cars were periodically checked for leaks on the long journey east. The cars performed well, encouraging the Densmores to fabricate the vat cars. They were also shrewd enough to protect their simple, yet effective, idea by a patent issued on April 10, 1866. Specifications consisted of the customary rambling, but cautious, text that claimed only as much novelty as the patent examiners would allow. It explained little, for in truth there was not much to be said, yet the text did specify wooden or iron tanks. Drawings of wooden tanks show that oil was loaded through a small square manhole on top of the tank and was emptied through a valve fastened to the low side.

Success breeded imitation and others began to feverishly copy the Densmores. An official of the largest fast freight car line in the oil fields, Charles P. Hatch of the Empire Line, immediately understood the potential of the Densmore concept. He cunningly sought to copy it, but not so closely that a patent fee might be required. He installed three square wooden tanks inside a boxcar early in 1866. Workmanship was defective and the tanks leaked so badly that Hatch’s car was pronounced a dismal failure. He then openly copied the Densmore idea and soon hundreds of vat cars were in operation. Bulk shipping even in small vat cars reduced transportation costs by five cents a gallon or $170 per carload, exclusive of the savings achieved by eliminating expensive barrels. Within a year after the Densmores inaugurated tank car shipments, greedy and inefficient teamsters were out of business.

Realizing the tank car’s significance, James Densmore sought ways to protect the invention. The original patent of April 1866 had little legal clout because of the pedestrian nature of the invention: it was simply a combination of well known elements – wooden tanks and a common flat car – and the patent was unable to claim anything beyond this simplistic combination. Ever the calculating businessman, Densmore understood this and intimidated imitators by creating a series of patents. Undoubtedly, he hoped that by announcing that the vat cars were protected by no less than four patents, competitors would assume that the design was considered novel and hence some substantial license fee was owed the patentees. He worked with a new business associate, George W.N. Yost of Corry, Pennsylvania.

George W.N. Yost was one of many mechanics and inventors Densmore both supported and dominated during the many years the typewriter was being developed. During their early association, Yost and Densmore concentrated on making money in the oil business. Their second, third and fourth tank car patents were issued on June 22, 1866. The second and third protected tank cars with three vats in place of two and examples were actually constructed on this plan. The fourth patent, a departure, illustrates a variety of four and eight wheel flat cars fitted with one, two and three rectangular wooden tanks. However, no cars are believed to have been constructed according to this plan.

The success of this battery of repetitious patents is actually peripheral because the defects of the Densmore design were quickly apparent. Surely an improvement over what existed before, they, nevertheless, constituted only a partial solution. The vertical tanks had a limited capacity because they could be made only as wide as the car – roughly eight feet – and only so high so as not to become top heavy. Even as the cars were built they were considered top heavy and unstable. The absence of baffles allowed the oil to surge about, adding to the sway and roll of the vehicle, especially when rounding curves. The vat cars were inherently dangerous because of the fragility of the wooden tanks, a loose collection of boards tethered together by bands, and the flammable cargoes they transported. In a major accident the Densmore cars were likely to shatter, disgorging a dangerous deluge of thick crude over the broken timbers of the wreck. The likelihood of a serious fire was also obvious.

Because of the many shortcomings, it is not surprising that the Densmores’ creation was made obsolete in just a little more than a year by a better tank car. New horizontal iron tanks resolved every defect of the obsolete vat car; they offered greater volume, a lower center of gravity, fewer leaks and far greater security in accidents. By constructing a large expansion dome at the top of the tank, the oil could safely expand if the sun’s rays warmed it. Gases could collect in the dome and be safely vented through an escape valve.

It was, in all, a rational design possessing such sound engineering principles that it has survived as the basic tank car plan to modern times. Just who actually devised it is uncertain, but surely the germ of the idea originated in Seely’s 1863 patent. As early as March 1867 a Titusville newspaper mentioned iron tank cars as the superior form although wooden cars still pre-dominated.

Iron cars, involved in an accident on the Allegheny Valley Railroad in February 1868, confirmed that they were in regular service by that time. Certainly some Densmore style cars remained in operation for many years, but it is unlikely many were built much after 1868.

James and Amos Densmore did not stay in northwestern Pennsylvania’s oil region to witness the demise of their brainchild. They had made their fortunes and left the oil fields in 1867 to pursue their typewriter mania. After many years, and the employment of many mechanics, including Yost, they achieved their goal. Many technological histories address their achievements in the development of the typewriter, but none mention their adventure into the design of the oil tank car that can best be described as “almost on the right track.”

For Further Reading

Darrah, William C. Pithole, The Vanished City. Gettysburg, Pa.: William C. Darrah, 1972.

Eaton, S.J.M. Petroleum: A History of the Oil Region of Venango County, Pennsyl­vania. Philadelphia: J.P Skelly & Co., 1866.

Giddens, Paul H. The Birth of the Oil Industry. New York: The Macmillan Company, 1938.

Giddens, Paul H. Early Days of Oil: A Picture History. Prince­ton: Princeton University Press, 1948.

Henry, J. T. The Early and Later Years of Petroleum. Philadel­phia: James B. Rodgers Company, 1873.

Maybee, Rolland H. Railroad Competition and the Oil Trade, 1855-1873. Mount Pleasant, Mich.: The Extension Press, 1940.

Miller, Ernest. The History of Pithole. Baltimore: Lord Balti­more Press, 1945.

Miller, Ernest. This was Early Oil. Harrisburg: Pennsylvania Historical and Museum Commis­sion, 1968.

Rosenberger, Homer T. Philadel­phia and Erie Railroad. Harris­burg: Pennsylvania Historical and Museum Commission, 1975.

John Hoxland White, Jr., has been a staff member of the Smithsonian Institution’s Division of Transpor­tation, National Museum of American History, since 1958. He has published seven books and nearly sixty articles on American railroad technology. His articles cover such diverse topics as rail­road hand cars and the first rail­road in China. His 1978 study, The American Railroad Pas­senger Car, was nominated for the National Book Award. A lec­turer at numerous historical societies, universities and museums, the author has given addresses at London’s Science Museum and the University of Moscow. A Short History of American Locomo­tive Builders, his most recent book, was published in 1982.