The Most Powerful Idea in the World

by William Rosen

  From professors of philosophy40 down to the humblest mechanic … [from] England, America, and Continental Europe. Every element and almost every substance were brought into requisition and made subservient to the great work. The friction of the carriages was to be reduced so low that a silk thread would draw them, and the power to be applied was to be so vast as to rend a cable asunder…. Every scheme which the restless ingenuity or prolific imagination of man could devise was liberally offered to the Company….

  The oversupply of perfect vacuums and perpetual motion machines was in part a testimony to the utter transformation of British cultural attitudes toward innovation over the preceding century. By the 1820s, the Patent Office was approving nearly three hundred new inventions annually, and rejecting thousands. In the event, the Liverpool & Manchester had made the conditions for entry fairly strict: entries had to be mounted on springs, weighing no more than six tons including water (if on six wheels) or four and a half tons (if on four); they must operate at between 45 and 60 psi, while being prepared for a test at up to 150 psi; they must consume their own smoke (to keep the route as clear of ash as possible; this effectively required the engines to burn coke rather than coal); and they were required to pull a gross load of twenty tons at ten miles an hour back and forth along a mile-and-a-half course forty times, reproducing the sixty-mile round trip between Manchester and Liverpool.

  The stipulations eventually weeded out all but five applicants, only three of which could be called serious. One of the others never actually made it to the starting line, and the other—the Cycloped, whose source of propulsion was a horse trotting on a treadmill and which was only allowed to compete because its designer was on the railway’s Board of Directors—proved good for nothing more than comic relief.

  Two of the remaining three competitors were joint favorites to win the prize: the Sans Pareil, built by Timothy Hackworth, master mechanic of the Stockton and Darlington Railway (and therefore George Stephenson’s former employer), and the Novelty, the creation of a former Swedish army officer now living in London, John Ericsson.

  The third, entered by Henry Booth and George Stephenson and to be built by his son Robert—Richard Trevithick’s rescuer, and an even more skilled engineer than his father—was Rocket.

  Between May and September of 1829, Robert Stephenson—who had promised his father, “Rely upon it, locomotives41 shall not be cowardly given up. I will fight for them until the last. They are worthy of a conflict”—labored at his workshop in Newcastle-on-Tyne to construct the world-changing locomotive. While it incorporated a key design feature suggested by Booth (the multitube boiler, about which more below), every other innovation contained in the final entry was the work of Robert, who had explicitly identified four areas for potential improvement in the final design: transmission of the largest amount of power from the pistons to the wheels; preservation of the greatest amount of traction between wheels and track; minimizing the loss of heat between boiler and cylinder; and maximizing the amount of heat within the boiler itself.

  Those innovations are the reason that any list of the most significant engines in locomotive history always includes the Stephensons’ entry at Rainhill, the site of the competition’s final trials. First were its mechanics: the way it transmitted the reciprocating motion of its pistons to its wheels. The “premium engine,” as the two Stephensons referred to it, used two pistons set at a 45-degree angle above the front axle, each one attached to a slip eccentric, which is a sort of linkage in which a disk is attached to an axle but offset “eccentrically” (essentially a simpler, and more efficient, version of the sun-and-planet gear). One set of slip eccentrics turned the reciprocating motion of the pistons into rotation, while another set worked in reverse, opening and closing the steam valves as the engine cycled.

  To increase the amount of traction between wheels and track, Stephenson and his assistant William Hutchinson calculated the optimal arrangement of weight over the wheels and determined to use the engine to operate only the front wheels; it was far more efficient, both in tractive power and durability, to drive only two large (4′8″ diameter) wheels and use the back wheels (with a diameter of 2′6″) for balance.

  Fig. 9: Little though it resembled the great locomotives of the nineteenth century, Rocket pioneered virtually all of their engineering innovations, from the high “blastpipe” chimney to the multitube firebox to the slip eccentric gears on the driving wheels. National Railway Museum / Science & Society Picture Library

  But the truly revolutionary significance of the engine was its boiler design. Twenty years before Rainhill, Oliver Evans had demonstrated that raising the boiler’s heat by doubling the amount of fuel increased the engine’s power by at least ten times; Richard Trevithick had goosed up the heat in his boiler with a U-shaped return flue. The principle was, in retrospect, obvious: Since the water was heated by conduction with the chamber containing heated gas, increasing the surface area of the chamber would transmit more of that heat to the water surrounding it. Robert Stephenson was just about ready to take that principle to its logical conclusion.

  Rocket’s boiler did not have a single flue, even a U-shaped one. Instead, as suggested by Henry Booth, twenty-five copper tubes, each three inches in diameter, were fitted into a firebox inside a water jacket, with somewhat wider copper tubes connecting them to the barrel of the six-foot-long, three-and-a-half-foot-diameter boiler. The cylinders exhausted their steam into two blast pipes inside the chimney, whose slightly narrowed openings guaranteed a powerful draft of air. Robert Stephenson spent the entire month of September testing to ensure that the boiler and cylinder were reliably steamtight to the point that they could handle up to 150 pounds of pressure per square inch. It finally passed Stephenson’s inspection only the day before it left his Newcastle workshop and was placed on a series of horse-drawn carts for the 120-mile journey to the Rainhill course, ten miles east of Liverpool.

  The first day of the trials, October 6, was largely a day for demonstration, as each competitor tried the course without hauling the weight required by the contest’s rules. Novelty, at two and a half tons, the lightest of the three remaining entrants, was by far the fastest. Using two vertical cylinders to drive a crank attached to the leading axle, it was also, by general consent, the prettiest engine in the competition (painted royal blue, with its boiler and water tank covered in polished copper), and it was made the early favorite, a position it improved on the following day, when, hauling more than eleven tons, Novelty easily hit a speed of 20 mph.

  On October 8, the final specifications for the contest were published: Each engine was no longer required to haul twenty tons, but a load of three times its weight, including the water in its boiler, with allowance made for the engines—Novelty and Sans Pareil—that hauled water in the locomotive rather than in a separate tender. Though the entrants were to have competed in the order of their “race cards”—Novelty, then Sans Pareil, then Rocket—the first two needed last-minute repairs, and Rocket went first.

  Rather surprisingly, given the historical significance and number of spectators, no one knows who actually drove Rocket on its October 8 debut at Rainhill. Robert McCree, from the Killingworth Colliery, had driven it during testing, but at least one report suggests that he was, like Robert Stephenson, only a passenger (and possibly a fireman, loading fuel into the firebox). If so, the driver could only have been George Stephenson himself, and he, like Rocket, covered himself in glory, along with coal dust. It took only fifty minutes for the fuel (like the other competitors, Rocket used cleaner-burning coke, to “consume its own smoke”) to bring the pressure in the boiler up to the required 50 psi from a cold start, and by 10:00 A.M., the engine was on its way.

  And so it continued. Aware that the rules mandated an average speed of 10 mph, the Stephensons kept their pressure well below its maximum for the first back-and-forth laps. It took a bit more than six minutes, at an average speed of around 15 mph, to complete the first mile and a half: just about
the pace of a good twenty-first century fifteen-hundred-meter runner. By the tenth lap, the engine was moving closer to 20 mph, but not until the last lap did the Stephensons open up the steam regulator and let Rocket fly. When they passed the grandstand at the eastern end of the course, Rocket was pulling its twenty tons at more than 30 mph, all while consuming “only” a little more than 200 pounds of fuel an hour. Thousands of spectators rushed the finish line to cheer the Stephensons on their triumph.

  The rest of the competition was something of an anticlimax. Novelty didn’t get a chance to compete until Saturday, October 10. The same high power-to-weight ratio that had made it such a fan favorite four days earlier allowed it to race off at what must have seemed magical speed, completing its first mile in less than two minutes. Before its second, however, a blowback from the engine’s furnace burst the bellows used to create chimney draft. The explosion ended Novelty’s day. On its next run, the favorite managed only one lap before another pipe exploded; since this was the pipe that fed the boiler, the resulting detonation ended with “the water flying in all directions.”42 When the boiler gave out, Ericsson gave up.

  Sans Pareil did perform brilliantly. The heaviest of the three finalists, it pulled a full twenty-four tons at better than 15 mph. But not for long. After twenty-two and a half miles, its boiler, rather embarrassingly, ran dry, melting the fusible plug that stopped it cold. The reason was its enormous consumption of fuel: nearly 700 pounds per hour.* The victor, by acclamation, was the Stephensons’ Rocket.

  IT’S NOT NECESSARILY OBVIOUS that the Rainhill Trials mark the moment in history when the steam revolution became finally, and utterly, inevitable. One year later, the Liverpool & Manchester Railway opened for business, with eight Stephenson-built locomotives traveling on Stephenson’s standard-gauge track before luminaries that included the then prime minister, the Duke of Wellington,† but the conflicts over the proper use of steam power didn’t vanish. To the end of his life, Stephenson fought a running battle with an even more famous engineer, Isambard Kingdom Brunel, over the latter’s preference for an “atmospheric railway system” operated by stationary engines. Brunel, the son of Marc Brunel, of the Portsmouth Block Mills, even designed the Great Western Railway to run on a gauge nearly three feet wider than Stephenson’s (though he soon discovered the impossibility of overcoming an early monopoly advantage).

  There is, after all, something as arbitrary about ending the story of the steam revolution at Rainhill in 1829 as beginning it in first-century Alexandria. Unfortunately for historians, if not for history, such convenient end points are as capricious as the textbook dates for the Industrial Revolution itself, which the careful reader will remember were originally matched as a lecture hall convenience to the regnal years of George III. One might just as well have decided that the story ended in 1819, the year that James Watt and Oliver Evans died—and, coincidentally, the year of the first steamship crossing of the Atlantic, by the American-built Savannah. Or 1824, when Sadi Carnot finally explained the thermodynamics of steam power. Or 1838, when I. K. Brunel’s Great Eastern connected a steam railroad with a true transatlantic steamer (the Savannah was really a three-masted sailer, with paddlewheels added).

  The reason for ending with Stephenson’s triumph nonetheless seems persuasive. Rainhill was a victory not merely for George and Robert Stephenson, but for Thomas Savery and Thomas Newcomen, for James Watt and Matthew Boulton, for Oliver Evans and Richard Trevithick. It was a triumph for the ironmongers of the Severn Valley, the weavers of Lancashire, the colliers of Newcastle, and the miners of Cornwall. It was even a triumph for John Locke and Edward Coke, whose ideas ignited the Rocket just as much as its firebox did.

  When the American transcendentalist Ralph Waldo Emerson met Stephenson in 1847, he remarked, “he had the lives of many men in him.”43

  Perhaps that’s what he meant.

  * The names of eighteenth-century Cornish mines are as personal, and as obscure, as the names given to thoroughbred racehorses and recreational sailboats.

  * Or, indeed, any form of thermal or electromagnetic energy. This particular bit of equivalence, the British Thermal Unit, is an early nineteenth-century measurement that has been mostly replaced by a frighteningly large array of units, including calories (and kilocalories), joules (and kilojoules), electron volts, kilowatt-hours, and therms, each of which can be converted to the others.

  * Some histories still insist that in 1543, a naval officer in the service of Charles V of Spain named Blasco da Garay used steam to propel a boat across Barcelona harbor, though the story has been thoroughly debunked for more than a century.

  * In the east end of the North Corridor on the first floor of the Senate wing of the U.S. Capitol is a series of frescoes painted by the Italian émigré artist Constantino Brumidi, thematically coordinated with the specific duties of Senate committees; over the doors leading to Room S-116, where the Committee on Patents originally met, are three portraits. Two of the subjects—Benjamin Franklin and Robert Fulton—are as well known as any names in American history. The third is John Fitch.

  * The Russell (or Scott Russell) linkage was actually invented and patented in 1803 by the watchmaker William Freemantle and only decades later named for the naval architect John Scott Russell.

  * Confusingly so. Steam is actually invisible; the clouds are just evidence that steam has condensed back into water vapor.

  * Literally; in addition to biographies of Watt, Smeaton, Maudslay, Dudley, Boulton, and dozens of other inventors and engineers, he also wrote, in 1859, the worldwide bestseller titled Self-Help: With Illustrations of Character and Conduct.

  * Not all of Stephenson’s historically significant inventions were associated with railroads, or even steam. His invention of a safety lamp, one that placed a barrier such as metal gauze between the candle and surrounding gas practically saved the deep coal mining industry. Stephenson’s eponymously named “geordie” was virtually simultaneous with a similar one invented by the Cornish chemist, and onetime partner of Richard Trevithick, Humphry Davy; the dispute over primacy continues to this day.

  * Hackworth never did accept his loss at Rainhill, and he and his supporters argued that the boiler failure was actually sabotage; perhaps imprudently, Hackworth had ordered it from Robert Stephenson’s workshop in Newcastle-on-Tyne. In the event, his accusation was dismissed, and the Liverpool & Manchester Railway ended up buying Sans Pareil.

  † The inaugural day for the Liverpool & Manchester is famous for the death of Liverpool MP William Huskisson, who was run down by Rocket. Just as widely reported, and far more lauded, was the heroic dash George Stephenson made in Rocket to the nearest hospital, during which he averaged 36 mph for fifteen miles.

  EPILOGUE

  THE FUEL OF INTEREST

  LEADVILLE, COLORADO, AT AN elevation of 10,152 feet, is the highest city in the United States, though the term “city” is generous; fewer than three thousand people live there, most of them directly or indirectly supported by tourism. Leadville, like many places in the American West, trades on its history, and it has more to trade on than most. Leadville was where Doc Holliday escaped after the legendary gunfight at Tombstone’s O.K. Corral, and the hometown to which the “unsinkable” Molly Brown returned after surviving the sinking of the Titanic. But most of the local color comes from local mines, from which millions of dollars in gold, and especially silver, were extracted in the last decades of the nineteenth century—enough, in fact, that Leadville is home to the National Mining Hall of Fame and Museum.

  It is also where, on October 11, 1962, the last regularly scheduled steam locomotive in the United States departed on its fourteen-mile trip to Climax, Colorado. The engine—#641 on the books of the Colorado & Southern Railway—used a multitube boiler fed by a blastpipe, just like Rocket. Just like Rocket, it ran on standard-gauge track, four feet eight and a half inches wide, just big enough to carry coal down the old wagonway at Killingworth Colliery.

  And just like Rocket, e
ngine #641, built in 1906 by Philadelphia’s Baldwin Locomotive Works, is practically an encyclopedia of engineering innovations, hundreds of them invented after the Rainhill Trials. In the 1840s, locomotives worldwide adopted a different linkage arrangement—the so-called “valve gear,” also a George Stephenson patent—but still connected pistons to wheels using slip eccentrics. By the time engine #641 was being designed, even Stephenson’s valve gear was supplanted by a different and superior version invented by the Belgian engineer Egide Walschaerts. Rocket’s angled pistons were replaced by horizontal ones. Fireboxes moved forward and back, wheel arrangements changed. Superior pressure gauges replaced the nine-foot-tall mercury tube used at the Rainhill Trials; air brakes were introduced, and then were replaced by ones using vacuum—necessary for stopping twentieth-century locomotives that could be one hundred and twenty feet long and weigh five hundred tons even without freight. By 1900, railroad track in Great Britain covered more than 48,000 miles; in Europe, more than 65,000. The United States, with its enormously greater territory, had laid 193,000 miles of track on its way to a 1930 peak of 230,000.

  As on land, so at sea. From the end of the 1860s through the 1920s, oceangoing ships turned their screws using engines with three or more cycles of expansion that were just a logical extension of the original compound engine, each cylinder using exhausted steam at lower temperature (and therefore pressure) in a greater volume of space, usually by increasing cylinder diameter. Since steam engines need fresh water, using the final stage of condensation for the boilers made possible the great steamships of the early twentieth century. Inventions created to move freight uncovered a new and highly profitable business in transporting large masses of people.

  Innovation in stationary steam engines was, if anything, even more dramatic. On March 10, 1849, the American George Henry Corliss received a U.S. patent for “certain new and useful improvements in Steam-Engines,” and he was being modest. The Corliss engine incorporated a rotary valve (and a version of Watt’s centrifugal governor) to offer variable control to the steam and exhaust ports in the cylinders, which resulted in a massive increase in efficiency and some extraordinarily massive engines: The Corliss Centennial Engine, forty-five feet tall, with a flywheel diameter of thirty feet, produced more than 1,400 horsepower and operated virtually every moving part at the Philadelphia Centennial Exposition of 1876.