The vast majority of trains on the planet depend on the friction (also known as adhesion traction) between steel drive wheels and steel rails to turn power into motion, but the somewhat slippery metal-on-metal action can only offer so much traction. Back in the 1880s, one man thought he could fix that.
Charles E. Swinerton attempted to literally reinvent the wheel by tossing out good ol’ round-wheel technology in favor of wheels configured as 210-sided polygons [Ed note: I believe that would be a dihectakaidecagon– Pete]. Swinerton’s steam locomotive, the Onward, was supposed to prove to the world that round train wheels were old news, and that his polygon tech was the future. Here’s why it didn’t catch on.
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Driving Trains On Polygons
Not much information is available online about Charles E. Swinerton or his company, the Swinerton Locomotive Driving Wheel Company. From what I could find online, Swinerton was from New York, and his company was based in Maine. The Swinerton Locomotive Driving Wheel Company wasn’t a one-man shop, and Swinerton assembled a team of company executives, most from New York.
It appears that the Swinerton Locomotive Driving Wheel Company’s principal product was Swinerton’s wheel invention. On December 1, 1887, Scientific American reported, the Hinkley Locomotive Works in Boston, Massachusetts, completed a locomotive designed by the Swinerton Locomotive Driving Wheel Company. Reportedly, Hinkley was told by Swinerton to spare neither labor nor expense to make the best locomotive the works could produce.
The locomotive, named Onward, was a bit of an anachronism in its time. It was built in a 4-2-2 arrangement, which meant four leading wheels, two driving wheels, and two trailing wheels. This type of design was reportedly seen as outdated due to the low adhesion of having only two huge driving wheels rather than multiple sets. It’s unclear why Charles Swinerton chose an outdated locomotive design, but it’s possible that Swinerton might have intentionally chosen the older, low-adhesion design to prove just how effective his invention was.
The big problem Swinerton had with round wheels was the very tiny patch between the hard steel wheel and rail. This wasn’t great for adhesion, and in Swinerton’s eyes, this was where the locomotive was ripe for what he thought would be a great technological leap.
Swinerton’s idea was simple: If the tiny contact patch of a round wheel is why locomotive driving wheels have poor adhesion, why not make a wheel where the contact patches are large and flat? Swinerton’s solution was to turn a wheel into a polygon. From Scientific American:
The principal feature of interest which the engine was built to illustrate is its driving wheel tires. These are covered by patents of C. E. Swinerton, president of the company. In outline each of these represents a polygon with sides one inch long, giving about 210 sides for the entire circumference. Looking at the wheel under favorable circumstances, the sidee are barely noticeable. If the light shines at the right angle upon the periphery, they can be clearly distinguished. A short straight edge, even a pencil sufficing, discloses the existence of facets by the rocking or oscillation as it passes from face to face. The exact angle of the facets is shown in Fig. 2.
The object of the polygonal wheel is to increase traction, and very remarkable results are claimed for it in this regard. Several ordinary engines have been fitted with the tire and have run for long periods in regular service. The ‘Onward,” with a single pair of drivers, is designed to put the wheels to the severest test. The first regular work of the “Onward” was in regular service on the Boston and Maine Railroad, where for six months it pulled the Portland express, a distance of 115 miles, with six to eight cars.
Scientific American notes that the wheels had 210 sides; however, other period reports, like one from The Engineer, noted variations 118 or 105 sides. Based on reporting, one determining factor of how many sides a Swinerton wheel had was the size of each side, or facet. Each contact patch was between one inch and two inches long, depending on the exact model of the Swinerton wheel. According to the Boston Herald in 1889, Swinerton claimed that the average train driving wheel of the day had a contact patch 1/16 of an inch long, so his wheel was a clear improvement – on paper, at least.
Scientific American also notes that the wheels were manufactured using a milling machine to create each facet. In theory, a damaged wheel would also be repaired through the same machine. A cost wasn’t specified, but it was reported that the creation of these wheels could be done for cheap.
Onward Into The History Books
The Onward weighed 45 tons and exerted 32,000 pounds on its 5-foot, 6-inch tall driving wheels. All of the locomotive’s wheels, save for the drivers, were made out of wrought iron. Drivers were made out of iron, except for the tires, which were made out of Krupp steel. Other notable features include 150 pounds of steam capacity, Westinghouse automatic and vacuum-operated brakes, and a built-in scoop to retrieve water from a trough.
The locomotive also featured a special pneumatic cylinder and lever designed to increase pressure on the driving wheels. When the cylinder was filled with air, it increased pressure on the driving wheels by up to 4,000 pounds for more traction.
The Onward was put through rather hard testing, from Scientific American:
Previous to this commission, the tractive power had been tried, and for several days it hauled 65 to 70 cars of coal from Boston to Lowell. This went to prove its capacity for handling loads usually pulled by four-driver engines. After the B. & M. runs were concluded in July, 1889, some special tests were made. A gradient of 87 feet to the mile was selected, and the number of cars which the engine could pull with and without sand was determined. Then the tires were turned off round and the same trials were repeated. The results as reported were remarkable, showing a great increase in tractive power from the use of polygonal tires.
The change of engineers was made to avoid any charge of partiality. One very peculiar result is the comparatively little difference in tractile power due to the use of sand in the case of the polygonal wheels. The disproportion in the loads moved by the polygonal and circular wheels is very striking in both cases. As regards practical points, it is found that the engine runs as quietly as any other.
The departure from the circle is too slight to occasion any rattling. In the first experiments, wheels with 2 inch facets were tried, and even they could not be distinguished in quietness of running from round wheels. In wearing, the facets do not disappear. It is found that a flat spot upon a tire in ordinary work never wears away. In like manner, the many flat spots on the Swinerton tire are preserved. An engine which ran 60,000 miles upon the Boston and Lowell R. R. with polygonal tires wore down in. from their periphery, but the characteristic surface was preserved to the last. Since the engine has been on the Jersey Central R. R. she has been pulling a train of five cars from Jersey City to Easton, Pa., a distance of 75 miles, with 14 stops, in two hours and two minutes.
Railroads Didn’t Bite
The claims, at least made by the testing published in trade journals, seemed to prove that a locomotive with only a pair of polygonal wheels had the traction of a locomotive with twice the driving wheels. The Swinerton wheel also did this without subjecting the locomotive to excessive vibrations or wearing out its own flat surfaces, according to Scientific American.
Yet, the Swinerton wheel never caught on. The locomotive and the wheels were trialed throughout the East Coast, but railroads did not bite. An official explanation was never given, but modern retellings of the story point out that Swinerton’s logic was flawed. He allegedly assumed that steel wheels did not deform, hence the hilariously tiny contact patch of just 1/16 of an inch. But in reality, steel does deform, at least a little. So the contact patch of a round wheel was actually larger than he believed.
Further, there were other practical issues with polygonal wheels, such as the fact that the locomotive brake pads of the era pressed directly against the wheel’s driving surface (as opposed to pinching a rotor or pressing pads against the sides of a drum, as we expect with a car) and were smoothly curved to match the profile of the wheel. As such, they weren’t as efficient acting on a polygonal wheel surface. And despite Swinerton’s claim the polygonal wheels could be made cheaply, they were still more expensive than plain round wheels. Apparently, railroads just didn’t see enough benefits for the added complexity.
Swinerton Tries Again
Looking at trade journals, it appears that Swinerton became a bit of a subject of mockery. In 1892, Locomotive Engineering reported that Swinerton might have failed to convince the railroads to buy his wheels, but maybe streetcar companies would want them instead:
Some mechanical fallacies are very hard to kill out. We supposed that the Swinerton polygonal wheel had lost its grip, but we find by a newspaper notice that the company which controls this peculiar invention are struggling to force it into use for street-car service. We understand that the Lobdell Wheel Co. are making cast-iron chilled wheels after the Swinerton design for street-car service. We hope they will be able to demonstrate more value for the thing than what surface railroads were able to do.
In 1895, the Electric Railway Gazette wrote that the Swinerton company had moved to Boston and was going all-in on marketing polygonal wheels for streetcars. Similar promises of huge improvements were made, from the Electric Railway Gazette:
The application of the wheel to electric railways has demonstrated that it possesses important advantages securing, it is claimed, more perfect traction, quick and complete control of car, overcomes grades, renders possible operation of cars with single motors, and draws the cars under all conditions of rail and weather without slipping and without sand. Until, however, something less than a year ago the wheel had never been applied to electric railway purposes. During this period its application has been closely watched, the defects have been remedied, and to-day it is claimed to be almost as perfect as it can be made.
It has been in operation the longest upon the Newton (Mass.) Street Railway Company and Superintendent Henderson has evidently subjected the wheels to the most severe tests and says that “the perfected wheel seems to cover just what is wanted by all electric roads, particularly those who run cars with single motors. The facets have a value. They reduce slipping to the minimum and help a car along greatly on a bad rail.” The new wheel weighs about 400 pounds as against 300 for the ordinary wheel, and it is claimed will run until worn out. The Newton Street Railway Company, it is understood, is equipping its cars as rapidly as possible with the latest form of Swinerton wheels. The Quincy & Boston Street Rail way Company is using them. The Norfolk & Suburban Street Railway Company is equipping with them as fast as possible and the Lynn & Boston road has a set of these wheels that it is expected will be running on this road in about a month.
Dead End Tech
Ultimately, the whole Swinerton wheel venture ended up being a dead end. It’s still not known exactly what went wrong. Perhaps Swinerton was too far ahead of his time. Perhaps putting polygonal wheels on a locomotive of an obsolete design was the wrong move. Maybe the railroads just didn’t see enough benefit to spend more on heavier, more complex wheels.
Whatever the reason, the Onward story had a sad ending. Once it was realized that the Swinerton wheel wasn’t going anywhere, the locomotive’s driving wheels were converted to regular round wheels, and the locomotive was sold to the Portland & Rochester Railroad. The locomotive would be rebuilt into a more typical design a few years later. Sadly, Onward only made it to 1905 before it was scrapped.
No rail equipment manufacturer today makes polygonal train wheels, but polygonal wheels are a thing – though not intentionally. Round train wheels can wear into a sort of polygonal pattern, and this wear is known to cause vibration, cracks, and worse issues.
Swinerton’s invention seemed promising. On paper, his wheel was a big improvement to an old technology, but convincing potential customers to care was a hurdle Swinerton could not get over. In the end, Swinerton technically reinvented the wheel, at least briefly. And though it was ultimately a failure, I still love the can-do spirit behind the idea.
Interesting. Wouldn’t those wheels be harder on the rails?
Im recalling an old “big wheel” with a flat spot on the drive wheel. Thump,thump, thump,…
Sounds like that guy was selling snake oil.
The small contact patch in a train wheel is what gives so little rolling resistance, and is therefore a bonus of that technology.
If he wanted better grip, using a softer metal would’ve made more sense, but again, who needs that in a train?
boring ass article. Do better.
I object to your comment.
We don’t do that here.
Did you forget the “/s”?
I liked it. Don’t be a jerk.
If you read a story about a train wheel design expecting excitement that’s probably a problem with you, not the article.
Regardless of the science behind the arguments both for and against, when it comes to polygonal wheels, there always another side.
Even if you assume the greater contact patch when pressed flat was superior, surely the Swinerton contact patch was infinitesimal when between facets?
Would be if nothing deformed, but metals do deform (wheel and track), and with the point down the point has huge stresses that deform it, and equal and opposite stresses on the track that is deformed as it is being bit into. It’s a mess.
Also, if lots of trains used the wheels, you might see wear patterns develop on the tracks akin to washboard roads or sand ripples at a seashore.
With the weight of the locomotive on it, even the slight lifting of that much weight as the wheel turned from a flat onto a point would surely increase the normal force on the rail tremendously, so even with a low coefficient of friction this peak due to lifting the locomotive could provide a benefit on traction on initial application of torque. Of course this also comes with a huge increase in local stress, possible slippage after the peak passes and the locomotive falls slightly into the next flat, and dramatic changes in these dynamics as the speed changes, but fundamentally the idea seems sound at least for low speeds or starting from a stop, even if it wasn’t worth the effort in the end. At high speeds it’s likely just skipping from peak to peak, so it could be quite a bit worse, especially if sudden braking is necessary, with more deformation so the rolling resistance would likely be hurt too
There’s not much point creating a faceted wheel when in a few thousand miles it will wear down to a circle.
Can I get a saving throw on that polygon?
Natural 210, you proceed down the tracks.
Physics does not support the claims of Swinerton. Multiple flat surfaces should cause mega vibrating. Even if it isn’t felt the actual surface area goes from bigger to much smaller when on the ends. Ang given the multiple parts needed to create the many flat surfaces not only would braking be Hindered but manufacturing and wear and tear cause much larger expenses. Frankly I don’t understand why they just don’t work on a higher friction material for the wheels
Train wheels have to be very hard so they don’t wear out. The number of hard yet high friction materials is zero.
This is why they increase traction using heavier engines with more driven wheels instead
I believe the convention is “two hundred ten”-gon, not “two hundred and ten”-gon, which would make it a dihectadecagon.
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