This Locomotive Drank So Much Fuel They Had to Invent a New Tank for It

Added: 2026-05-09

[00:00:00]Imagine standing beside a stretch of railroad track somewhere in the emptiness of Wyoming. The year is 1959.

[00:00:08]The sky is wide open, the air is cold, and the only sound is wind cutting across dry grass. Then something changes. A distant rumble begins to build. Not the familiar rhythm of a diesel engine, not the nostalgic chug of steam, but something altogether different. something that sounds more like a fighter jet than a train. The ground beneath your feet begins to vibrate. The vibration climbs up through your boots, into your legs, into your chest. And then it appears on the horizon, a massive yellow machine, impossibly long, moving with a kind of authority that no locomotive before it had ever possessed. Birds scatter from the telegraph wires. Jack rabbits bolt across the plane. And the sound, that high-pitched, relentless whale washes over everything within miles.

[00:01:01]This was the Union Pacific Big Blow. The most powerful locomotive ever operated on North American soil. A machine that defied engineering convention, rewrote the rule book on what a locomotive could do, and then vanished from the rails so quickly that most people today have never even heard of it.

[00:01:20]How does something this extraordinary get erased from history? And why did the most powerful locomotive ever built last less than two decades before being quietly cut apart and melted down? That is the story we are telling today. And trust me, you are going to want to stay until the end. Before we go any further, if you are the kind of person who finds yourself completely absorbed by forgotten engineering achievements and the untold stories behind them, this channel is built for you. Subscribe now because every week we go deep into the machines, the decisions, and the consequences that shape the world we live in. Now, let us go back to where this story begins. Because before the big blow could exist, there had to be a problem serious enough to push an entire railroad company toward an idea that on paper sounded almost insane. In the early 1950s, Union Pacific Railroad was staring at a geographical reality it could not argue with. East of Ogden, Utah, the Wasach Mountain Range rises dramatically from the high desert floor.

[00:02:28]And for any freight train heading eastbound, that meant climbing a continuous grade for roughly 65 miles at a slope of 1.14%.

[00:02:38]Now 1.14% might sound trivial. It might even sound almost flat, but let me give you some perspective on what that actually means when you are talking about freight trains. A fully loaded coal or merchandise train in that era weighed several thousand tons. The contact between steel wheels and steel rails, that thin strip of metal-on-metal connection that carries the entire weight of the train, offers almost no friction, almost no grip. A steel wheel on a steel rail is one of the most efficient surfaces for rolling that humans have ever engineered. That efficiency is the whole point of railroads. But on a grade, that same efficiency becomes a serious vulnerability. The locomotive has to fight not just inertia, but gravity, pulling thousands of tons backward down the slope. Union Pacific had been throwing its most powerful machines at this grade for years. Their crown jewels at the time were the legendary Big Boy steam locomotives, engineering marvels in their own right. Each big boy weighed approximately 400 tons, ran on 16 massive drive wheels, and was already considered among the most capable freight locomotives ever constructed.

[00:03:54]These machines had been built specifically with western mountain grades in mind. But by the early 1950s, even the big boys were being pushed to their limits. And more importantly, the railroad industry was shifting. Steam was on its way out. Diesel electric locomotives were taking over American railroads with breathtaking speed because they were cleaner, simpler to maintain, and more reliable than their steam predecessors. The trouble was horsepower. A typical diesel locomotive of that period produced around 1,500 horsepower per unit. A single big boy could deliver far more than that from one machine.

[00:04:35]To match what a big boy could do on a mountain grade, Union Pacific would have to couple together four, five, sometimes six diesel units, each with its own crew requirements, its own maintenance schedule, its own potential failure points. That was not a solution. That was a compromise.

[00:04:54]And Union Pacific's chief engineers were not interested in compromises. So they started asking a question that no American railroad had seriously asked before.

[00:05:05]What if the answer was not a bigger diesel? What if the answer was not a diesel at all? The jet age was dawning.

[00:05:13]After World War II, gas turbine technology, the same fundamental principle that powered military aircraft, had advanced dramatically. A gas turbine operates by compressing air, mixing it with fuel, igniting that mixture, and using the resulting high-speed exhaust gases to spin a turbine shaft at enormous speed. The power output relative to the physical size of the engine was by the standards of any piston-driven machine.

[00:05:42]Staggering.

[00:05:43]The idea that Union Pacific began developing in the late 1940s was this.

[00:05:49]Take a gas turbine engine, mount it inside a locomotive body, use it to spin a large electrical generator, and then route that electrical power to traction motors mounted on the locomotive's axles. It was not a new concept in its broad strokes. Diesel electric locomotives already operated on the same generator and motor principle, but replacing the diesel engine with a gas turbine meant accessing a level of raw horsepower that no piston engine could come close to matching. The railroad approached General Electric, which already had extensive experience with turbine technology from its aviation and industrial work. The collaboration that followed would produce one of the most remarkable chapters in American mechanical history. In 1948, General Electric delivered a prototype, initially designated GE101, later repainted and reumbered as UP50, that rolled out of the Eerie, Pennsylvania manufacturing facility carrying a gas turbine rated at 4,800 horsepower. Union Pacific applied their signature armor yellow paint, fitted the locomotive with their standard lettering, and sent it west for testing across Wyoming and Utah. The prototype ran rough. There were mechanical teething problems, as there always are, with experimental machinery pushed far beyond what existed before. But the core concept proved itself on those test runs in a way that mattered more than any rough edge. A gas turbine locomotive could haul freight. It could do so with fewer moving parts than a steam engine, and it could produce power that outclassed anything diesel technology was offering at the time. There was, however, a catch. One enormous, inescapable catch buried in the turbine's design. Gas turbines are fundamentally less fuel efficient than diesel piston engines when you compare them horsepower for horsepower.

[00:07:46]A turbine of the scale Union Pacific was testing consumed roughly twice as much fuel as an equivalent diesel engine would have burned to produce the same power output. Think about what that means operationally. Double the fuel, double the fuel cost. On a railroad network where locomotives are running thousands of miles every week, that kind of fuel penalty should have killed this project before it ever left the engineering department. But Union Pacific's engineers had identified something clever. They had found a loophole in the economics of fuel itself. The loophole had a name. Bunker C heavy fuel oil. Bunker C was the residue that remained at the bottom of the refining process after everything valuable had been extracted from crude oil, the gasoline, the diesel, the kerosene, the aviation fuel. What was left behind was a thick, dark, extraordinarily viscous substance that behaved less like a liquid and more like cold tar or thick molasses at ambient temperatures. Oil refineries in that era had almost no profitable market for bunker sea. It was essentially industrial waste that they could barely give away. Union Pacific could purchase bunker sea for a fraction of what standard diesel fuel cost, sometimes as little as one quarter the price. And when you run the mathematics of that price differential against the turbine's higher consumption rate, something remarkable happens. Even burning twice as much fuel, the turbine was still cheaper to operate per ton mile than a diesel locomotive burning conventional fuel. The economics worked on paper. But now came the engineering challenge that nobody would have anticipated if they had not actually tried to use this fuel.

[00:09:29]Because getting bunker C to cooperate was a project unto itself. Picture trying to pump cold molasses through a series of pipes, filters, and precision fuel injection nozzles. That is roughly analogous to what bunker sea fuel oil does at room temperature. It does not flow. It barely moves. You could pour it from a container and watch it creep downward with agonizing slowness in colder temperatures. And remember, these locomotives were operating in Wyoming winters. The situation was even worse.

[00:10:04]Union Pacific's engineers solved this with a solution that was elegantly simple in concept, extraordinarily demanding in practice. They built heating systems directly into the locomotives fuel delivery infrastructure. The bunker sea had to be warmed to approximately 200° F before it would flow with enough fluidity to be pumped and injected into the turbine's combustion chambers. Once that heated fuel entered the combustion chamber, however, the results were spectacular.

[00:10:35]The ignition temperature inside those chambers reached around 1,400° F. The expanding gases that resulted from combustion drove the turbine blades with tremendous force. And those blades, spinning at speeds that seemed more appropriate to an aircraft engine than anything on a railroad, transmitted their rotational energy through the generator and ultimately to the traction motors moving the locomotive forward.

[00:11:03]Union Pacific had its answer, a turbine that worked, a fuel that was cheap enough to make the economics function.

[00:11:12]Now, could this actually be made into a production locomotive? In 1952, the first production order rolled out of General Electric's facility. 10 locomotives numbered up P-51 through EP60, each rated at 4,500 horsepower, ready to go to work on the main line connecting Council Bluffs, Iowa to Ogden, Utah, the heart of Union Pacific's operational territory. But those first production units immediately revealed a new problem that the prototype testing had not fully exposed.

[00:11:44]Each of those first 10 turbines carried onboard fuel tanks holding approximately 7,200 g of bunker C. That sounds like a substantial reserve until you understand the turbines appetite at operating power. These locomotives could drain their onboard tank in just a few hours of heavy operation. On a long hall from Council Bluffs to Ogden, a run of several hundred miles through demanding terrain, a single turbine might need to stop for refueling multiple times. That was a fundamental operational problem.

[00:12:16]One of the primary arguments for using these high-ower locomotives was simplicity. One powerful machine instead of a string of smaller units. But if that one machine had to stop for fuel more often than the journey required, it was undermining its own purpose. The solution came from an unexpected direction. The railroad's own junkyard of history. Union Pacific's mechanical department looked at the retired tenders from their decommissioned steam locomotives. The large cars that had once carried coal and water behind the big boys and other steam engines and recognized them as a ready-made reservoir waiting to be repurposed.

[00:12:56]Workers stripped the old coal bunkers out completely. They rebuilt the interior tanks to handle liquid fuel.

[00:13:04]And critically, they wrapped the entire tank structure in 4 in of glasswool insulation to maintain the elevated temperature the bunker C required to stay fluid. These converted tenders held approximately 24,000 gall of heated fuel, more than three times the onboard capacity of the locomotive itself.

[00:13:23]Coupled permanently to the rear of the turbine unit, they transformed each locomotive into a two-piece assembly capable of genuine long-d distanceance operation without constant refueling stops. The railroad had essentially learned through painful experience what the turbines actually needed. And the solution they developed led directly to the next more ambitious phase of the program. By 1954, Union Pacific was confident enough in the turbine concept to order 15 more locomotives numbered 61 through 75. These second generation units came with an external design difference that immediately set them apart from the first series. Open walkways running along the sides of the locomotive body that gave them an airy gallery-like appearance. Crews and observers began calling them verandas almost immediately. and the name stuck.

[00:14:17]Each Veranda unit came factory paired with its 24,000gal insulated fuel tender from the outset. Union Pacific had stopped treating the tender as an add-on and recognized it as a fundamental component of the locomotive itself. No turbine was going anywhere without its rolling fuel supply. The verandas performed well, but Union Pacific's leadership was already looking beyond them. Because if a 4,500 horsepower turbine worked, what would happen if you more than doubled that output? The answer to that question would define what many historians and engineers consider the most audacious locomotive order in the history of American railroading. In 1955, Union Pacific placed an order for 30 new gas turbine locomotives. The specification attached to that order contained a number that caused genuine disbelief when it circulated through the railroad and locomotive manufacturing industry. 8,500 horsepower from a single gas turbine engine. Let that figure sit for a moment. The standard diesel locomotive of 1955 produced around 1,500 horsepower. These new turbine locomotives would generate more than five times that output in a single machine. Even comparing it to the big boy steam locomotives that had once represented the absolute pinnacle of American motive power, the new turbines were operating in a different category entirely. The engine at the heart of these machines was a General Electric frame 5 gas turbine. A massive sophisticated piece of engineering that had itself evolved through years of industrial and aviation turbine development. Getting 8,500 horsepower out of it required feeding it enormous volumes of heated bunker sea at high pressure, maintaining precise combustion conditions, and managing exhaust flows that generated temperatures and velocities most people would associate with industrial furnaces. The mechanical configuration that Union Pacific and General Electric developed to house all of this was itself a remarkable piece of engineering architecture. Each complete locomotive consisted of three separate but permanently coupled units. The A unit at the front contained the crew cab, all the operator controls, and a separate 850 horsepower diesel engine built by Cooper Bessemer. This small diesel existed purely for what railroad people call hostling, moving the locomotive slowly around rail yards and terminals without firing up the main turbine. As you will understand shortly, running the turbine in confined spaces was not something anyone wanted to do.

[00:17:00]The Bunit, coupled directly behind the Aunit, housed the main gas turbine itself, along with the large electrical generators it drove and the sophisticated power distribution equipment that routed electricity to the traction motors on both units. The B-unit was essentially a self-contained turbine power plant on wheels. And trailing behind the B-unit came the now familiar insulated fuel tender, carrying its 24,000 gallons of heated bunker sea across whatever terrain lay ahead. The combined length of this three-piece assembly was approximately 179 ft from end to end. Fully loaded with fuel, the entire consist weighed in the vicinity of 610 tons. To place that in modern context, 179 ft is roughly the length of a Boeing 737 commercial airliner. Union Pacific was operating machines the length of jet aircraft across the high plains of Wyoming and Utah. The performance numbers matched the scale on level track. Under ideal conditions, these locomotives produced their rated 8,500 horsepower. But in cool, dense air, the kind you find at altitude on a Wyoming morning in January. The turbine's output climbed beyond its rated figure. Cold air is denser air, and denser air means more oxygen per cubic foot entering the combustion chamber, which means more fuel can be burned, which means more power. Union Pacific's engineers recognized what the data was showing them and eventually upgraded the official rating of all 30 units to 10,000 horsepower. 10,000 horsepower from one locomotive. No North American locomotive before or since has ever matched that figure from a single prime mover. What does 10,000 horsepower sound like when it is enclosed inside a locomotive body and vented through exhaust stacks at roughly 150 mph? It sounds like nothing else that has ever operated on a railroad. The exhaust gases leaving those stacks reached temperatures approaching 850° Fahrenheit. The velocity at which they exited the locomotive created a sound that witnesses consistently described not as a rumble or a roar, but as a sustained high-pitched whale. The acoustic signature of a massive jet engine translated to the surface of the earth and pointed horizontally down a railroad track. You did not just hear the big blows. You felt them. Railroad workers who regularly stood near the main line described the vibration as something physical, a pressure in the chest, a resonance in the bones that no diesel locomotive produced. The nickname Big Blow emerged almost spontaneously among crews and railroad workers. It required no marketing, no official designation. Anyone who had experienced one of these locomotives operating at full throttle understood immediately why the name fit, but the sound created operational challenges that Union Pacific had not fully anticipated. In a rail yard where locomotives needed to be maneuvered at low speeds for switching and positioning, the turbine was essentially useless. Running it for yard work would have created noise conditions dangerous for yard workers and impossible for crew communication.

[00:20:27]This is precisely why the 850 horsepower auxiliary diesel existed. Yard movements ran on the small diesel and the turbine stayed cold until the locomotive reached open track. Even the air horns required special attention. The original horn placement on the cab roof was quickly abandoned because the turbine sound was so overwhelming that crews inside the cab genuinely could not hear their own horns. The horns were relocated to the midsection of the A unit. And even then, in heavy turbine operation, the margin between locomotive noise and horn sound was uncomfortably thin. And then there was what the exhaust did to its surrounding environment. The thermal energy pouring out of a big blow's exhaust stack was significant enough to cause property damage under certain conditions. When a big blow pass beneath a road overpass at full operating power, the concentrated heat and velocity of the exhaust could soften and in some cases begin to melt asphalt road surfaces. It was not a common occurrence, but it happened often enough to be documented and discussed within the railroad industry. The wildlife impact was more dramatic and frankly more disturbing. The dense hot exhaust plume trailing behind a big blow at full throttle was lethal to any bird that flew through it. The combination of extreme temperature and the chemical composition of bunker sea combustion products left nothing airworthy on the other side. This grim reality earned the big blows a second nickname among people who worked around them. the bird cooker.

[00:22:07]Out across the open landscapes of Wyoming and Utah, these side effects were manageable. The nearest human structures were often miles away.

[00:22:16]Wildlife populations were robust. The trains ran their routes, hauled their freight, and the consequences of their operation were absorbed by the emptiness of the western landscape. But Union Pacific grew ambitious. and ambition in this case led them directly into a confrontation they were not prepared for. In the early 1960s, Union Pacific began exploring the possibility of deploying the big blows on routes connecting Salt Lake City to Los Angeles. The logic was straightforward from a freight perspective. More power, fewer locomotive units, greater efficiency on long runs through difficult terrain. What nobody had fully gamed out was what happened when you ran a machine producing this level of noise and exhaust through the suburban communities that had grown up along the California portions of the route. The results were almost immediately catastrophic from a public relations standpoint. Residents living near the tracks reported the turbine noise as something qualitatively different from anything they had experienced before.

[00:23:20]Loud enough to be clearly audible from several miles away. physically disorienting up close. Dishes were reported vibrating off kitchen shelves.

[00:23:30]Cracks appeared in plaster walls. The low frequency vibration that accompanied the high-pitched turbine whale penetrated building structures in ways that normal locomotive noise did not.

[00:23:41]Local governments in Southern California moved quickly. City councils passed ordinances. Complaints piled up. The political pressure on Union Pacific from homeowners, local officials, and state representatives became untenable. By approximately 1962, Los Angeles had effectively closed its rail corridors to the turbine locomotives. City after city along the California route followed. Union Pacific withdrew the big blows from California operations without much public announcement. The locomotives were quietly reassigned back to their home territory. the open, sparsely populated corridor between Council Bluffs and Ogden, where their noise signature was a curiosity rather than a complaint. The California experiment was closed. And while the big blows continued their work on the eastern routes, a set of economic forces was gathering that would prove far more damaging than any city council's vote. The entire financial architecture of the gas turbine program rested on one assumption. And by the mid 1960s, that assumption was beginning to crack. Bunker sea fuel oil would stay cheap because nobody wanted it. That had been true in the late 1940s and through most of the 1950s.

[00:25:01]Refineries genuinely had limited markets for their heaviest residual fractions.

[00:25:06]The economics of the petroleum industry at that time did not offer efficient pathways for converting those heavy oils into more valuable products. But the post-war prochemical industry was evolving rapidly. The plastics revolution of the 1960s was creating enormous demand for hydrocarbon feed stocks and refineries discovered that heavy residual oils, the Bunker Seaggrade and others like it, contained raw material that was suddenly quite valuable as a feed stock for chemical processing. Simultaneously, advances in catalytic cracking technology were giving refineries new tools to convert heavy fractions into lighter, higher value fuel grades that could be sold at premium prices. The result was entirely predictable in retrospect. The price of Bunker C began rising, not dramatically overnight, but steadily, persistently, in a direction that eroded the turbine program's cost advantage with every passing quarter. And here is the aspect of this economic problem that made it particularly punishing for Union Pacific's turbines specifically. A diesel locomotive at idle burns a small fraction of the fuel it consumes at full operating power. The relationship between power output and fuel consumption in a diesel engine is relatively proportional. Run it at 20% power and it burns roughly 20% of its maximum fuel consumption. This is enormously useful operationally because locomotives spend significant time idling, waiting in yards, pausing on sightings for opposing traffic to pass, sitting at terminals between assignments. A gas turbine does not work this way. The thermodynamic inefficiency of a turbine at low power settings is severe. A big blow sitting in a sighting waiting for a freight train to pass consumed fuel at nearly the same rate as it did hauling 5,000 tons over Sherman Hill at full throttle. The turbine had to be kept warm, kept spinning, kept fed with heated bunker sea regardless of whether it was doing useful work or not.

[00:27:14]As fuel prices rose, every hour of forced idling became a direct financial loss that grew larger quarter by quarter. The operational patterns that the railroad depended upon, sightings, meats, terminal delays, were essentially invisible when bunker C was nearly free, but they became painfully visible as the price climbed. Rising operational costs would have been survivable if the locomotives themselves had remained in good mechanical condition. But bunker sea fuel was not just expensive to burn.

[00:27:47]It was actively destroying the machinery. It was burning inside. The combustion products of Bunker C are far more corrosive than those of cleaner diesel fuel. The sulfur content, the heavy metal compounds present in residual oil, and the carbon soot produced during combustion, all accumulated inside the turbines precision internals.

[00:28:09]Turbine blades, components that must maintain extremely tight dimensional tolerances to function correctly, experienced accelerated erosion.

[00:28:19]Combustion chamber liners degraded faster than engineering schedules had projected. Fuel injection nozzles clogged and corroded. The elaborate heating systems required to keep the bunker sea flowing needed constant maintenance attention. The skilled technicians required to properly service gas turbine equipment were not standard railroad shop workers. Union Pacific had to develop specialized training programs and maintain dedicated facilities capable of handling turbine work. Every maintenance event cost more than an equivalent intervention on a diesel locomotive, and the maintenance events were becoming more frequent as the machines aged and as the cumulative damage from bunker sea combustion accumulated.

[00:29:05]The cost per ton mile for these locomotives, the fundamental measure of railroad operational efficiency, was climbing steadily in the wrong direction.

[00:29:15]Meanwhile, the diesel locomotive manufacturers had not been standing still. Through the late 1950s and into the 1960s, both General Electric and the electrootive division of General Motors were pushing their diesel electric designs progressively higher in power output. By the mid 1960s, new diesel models were approaching and then exceeding 3,000 horsepower per unit.

[00:29:41]Couple two of them together and you had 6,000 horsepower. Three units gave you 9,000 horsepower, numbers that began to approach big blow territory. And these diesel locomotives offered everything the turbines could not. They burned conventional fuel that was commercially priced and widely available at every fuel point on the railroad. They idled efficiently without draining fuel reserves. They could operate anywhere on the network without noise complaints, and they required maintenance from the same skilled shop forces that already handled the rest of the railroads diesel fleet. The argument for gas turbines was not just weakening, it was collapsing.

[00:30:24]Union Pacific's management could see the trajectory clearly. The decision that followed was not a dramatic crisis moment. It was the quiet inevitable conclusion of a careful financial analysis. The retirement of the Big Blow fleet began in August 1968 when units numbered 1 through 4 were withdrawn from service. These locomotives had been in revenue operation for barely a decade at that point. An extraordinarily short service life for machines of their capital cost and engineering investment.

[00:30:57]Through 1969, the retirement process accelerated. One by one, the turbines were pulled from their assignments, moved to storage tracks, and assessed for whatever salvageable components remained. Unit number seven earned a quiet footnote in railroad history as the last big blow to haul an actual revenue freight train, making its final working run on December 26th, 1969, the day after Christmas, with almost no ceremony and no announcement. The final two operational units, numbers 18 and 26, were held in storage at the Cheyenne Roundhouse in nominally running condition for several more weeks before being officially retired in February 1970.

[00:31:42]And then Union Pacific did what railroads almost always do with machines that have outlived their usefulness.

[00:31:47]They took what was worth saving and sent the rest to the scrapyard.

[00:31:52]The traction motors, trucks, and mechanical components that could be adapted for use in other applications were harvested from the retired turbines and incorporated into General Electric's new diesel locomotive designs. The U50 and U50C models that were already entering service. The 24,000gal insulated fuel tenders were drained, cleaned, and converted into water supply cars for track maintenance operations.

[00:32:20]Some of those former turbine tenders eventually found an unexpected second life, coupled behind Union Pacific's preserved steam locomotives, the famous 844 and the restored Big Boy 4014, where they now carry water instead of Bunker C on excursion runs. of the 55 gas turbine locomotives that Union Pacific operated across the entire program. From the 1948 prototype through the last Big Blow, 53 were scrapped. The cutting torches moved through the fleet without sentiment or hesitation. Only two third generation Big Blow locomotives escaped the scrappers torch. Unit 18 stands today at the Illinois Railway Museum in Union, Illinois, displayed as a complete three-unit consist alongside its original fuel tender. The turbine is still physically present inside the B-unit, though many secondary components were removed before the museum acquired the locomotive in 1993.

[00:33:22]It is a static exhibit, nonoperational, but intact enough to communicate the sheer physical scale of what it once was. Unit 26 is displayed outdoors at the Utah State Railroad Museum near the historic Union Station in Ogden, Utah.

[00:33:39]The same Ogden that was the western terminus of the turbine's primary operating route and the gateway to the very Wasatch grade that made these machines necessary in the first place.

[00:33:50]It too is static and nonoperational.

[00:33:53]Neither museum has announced any active restoration program. The technical complexity and cost of returning a gas turbine locomotive to operational condition would be extraordinary under any circumstances and the specialized expertise required to work on this specific turbine technology has largely dispersed over the past half century. If you visit either of these surviving machines and walk the full length of the consist from the nose of the A unit past the Bunit housing to the far end of the fuel tender, you will cover approximately 179 ft. That is roughly the length of a Boeing 737 on the gate just sitting on museum rails in the open air. The exhaust stacks that once vented 850°ree gases into Wyoming skies still point upward, silent now and gradually weathering under decades of sun and wind. Union Pacific's gas turbine program lasted from the first prototype in 1948 to the final revenue run in December 1969.

[00:34:58]Roughly 18 years of operation. In that span, these machines established power records that have never been surpassed in North American locomotive history. A record that still stands more than 50 years later, which in an era of rapid technological change is remarkable by any measure. At their operational peak, the turbine fleet was handling more than 10% of Union Pacific's entire freight tonnage. For the mountain grades of the American West, where no diesel combination of that era could match what a single turbine could do, they were genuinely indispensable.

[00:35:33]But they were also products of a very specific set of economic conditions that no engineer or manager could permanently guarantee.

[00:35:42]Cheap fuel, limited competition from diesel technology, and the particular geography of Union Pacific's mountain roots. All three of those conditions eventually changed. And when they changed, the financial case for these extraordinary machines evaporated with surprising speed. There is a larger lesson buried in this story, one that goes well beyond locomotives and fuel oil and mountain grades. The most powerful solution to a problem is not always the most durable one. Sometimes the winning design is not the one that achieves the most impressive performance numbers, but the one that survives the widest range of changing circumstances.

[00:36:23]The big blows were supreme on their home territory under the conditions for which they were optimized.

[00:36:30]Move them to California and they became a public relations problem. Watch fuel prices rise and they became a financial liability. wait for diesel technology to advance and they became obsolete. They were too loud for cities, too thirsty for an era of rising energy costs, too specialized for a railroad network that needed flexibility more than it needed sheer peak power. But for those 18 years, roaring across the empty stretches of Wyoming at 10,000 horsepower, hauling freight loads that would have required half a dozen diesel [clears throat] units, making the ground shake and birds flee and railroad workers press their hands to their chests to feel the turbines vibration.

[00:37:14]There was nothing like them anywhere on Earth, and there never has been since.

[00:37:20]So, here is the question I want to leave you with. In an era when engineers are once again exploring alternative power sources for heavy transportation, hydrogen turbines, battery electric systems, hybrid power plants. Is there a version of this story waiting to be written again? Is there another revolutionary power source being deployed today that solves today's problem brilliantly, but carries within it the seeds of tomorrow's obsolescence?

[00:37:47]Think about that the next time you hear about a breakthrough in transportation technology. And if you want to explore more stories like this one, engineering achievements that changed history and then disappeared, there is another one waiting for you