--- title: "Nuclear Trains: Why We Can't Have These..." description: "The idea of a nuclear train was one of many engineering projects that was born out of the mid-20th century nuclear boom. This period paved the way for hundreds of theoretical ways scientists could use nuclear power to improve our everyday lives, and transport made up a large part of that list.\n\nNuclear powered aircraft, submarines, cars, aircraft carriers, and trains were all seen as very realistic possibilities, but only some of them became reality.\n\nNuclear trains, for one, were seen as an easy enough upgrade from traditional locomotives, one that would save on fuel and lower the entire planet's carbon footprint. There were, in fact, several detailed designs, some of which were even patented, and even military projects with government backing.\n\nHowever, despite the vehement enthusiasm surrounding the idea, after careful analysis, it was concluded in every single case that developing a nuclear locomotive simply made no sense. Here's why.\n\n## Where It All Began\n\nIn the 1950s, nuclear power was in its infancy. Although some scientists very accurately predicted its capabilities, nuclear power was, at the time, a new field of exploration. As it started becoming more and more apparent that humans have just stumbled upon a source of energy so powerful it could seemingly solve all the world's problems, brand new engineering ideas started surfacing left, right, and center. All of a sudden, 'nuclear' was the one size fits all solution for all the world's problems, and trains were just another entry on the list of things we could improve with nuclear energy. This idea is, more than anything, a product of its time.\n\nIn theory, nuclear trains could entirely replace traditional locomotives that have to stay close to power lines or regularly stop to take on coal or oil. A nuclear train could keep chugging down the rails for months, or maybe even years before refueling. In fact, the X-12, the world's first design for a nuclear locomotive, could have, in theory, traveled around the world twice before its first refueling. We, of course, can't know this for certain, as the X-12 was never built, but the man behind its design, Dr. Lyle Borst, said that in an interview with *Life* magazine.\n\nAside from the astounding fuel efficiency, a nuclear train would also make power line maintenance much easier. Since it would operate completely independently, without any reliance on the electric grid, less time and fewer resources would have to be invested into maintenance. This would be especially useful in countries such as the United States and the USSR, which have hundreds of kilometers of train tracks dislocated far away from populated areas.\n\nA nuclear locomotive could do all of that while minimizing its carbon footprint. That, unfortunately, wouldn't have been quite the selling point in the 1950s as it is today as the public wasn't as informed about the potential impact of rising levels of carbon dioxide. It was, however, important to physicists, who were well aware of how important the lowering of our collective carbon footprint could become.\n\nWith all of these positives, it's only natural that the two greatest world powers at the time, the United States and the USSR, showed affinity toward the idea.\n\n## Designs and Real Life Applications\n\nThere were dozens of atomic train ideas and proposals around the entire world at the time, but the first to present an actual design with feasibility calculations was the aforementioned Dr. Borst of the University of Utah.\n\nWe've already done a deep dive on Dr. Borst's X-12 if you're interested in a detailed breakdown, but in short, the X-12 was a breathtaking idea at the time.\n\nThe locomotive would be powered by an atomic reactor which would split uranium atoms, release tremendous amounts of energy in the form of heat, and generate steam by boiling water. The steam would pass through a pressurizer and rotate turbines, which would be connected to generators, converting the mechanical energy into electrical. This is, in essence, how all nuclear power plants work, only this generator would be small enough to fit in a locomotive.\n\nThe massive electric motors would produce 7000 horsepower and roll the train onwards. The X-12 would predominantly transport cargo, but it could, over time, become a passenger train too.\n\nThe Soviets had a similar idea, albeit two years after the Americans. In 1956, the Ministry of Transport kickstarted a campaign for several atomic train designs. It's no surprise that the Soviets were particularly interested in nuclear-powered trains—they had one of the largest railway networks in the world at the time, and the idea of saving on fuel was certainly tempting.\n\nOne of those designs was made by the forgotten Soviet engineer Yuriy Moralevich, who also happens to be one of the engineers behind the world's first nuclear-powered icebreaker, and the world's first nuclear-power ship in general—*The Lenin*. Moralevich planned to completely revolutionize the Soviet railway system.\n\nFor one, the train he had designed was not only a double-decker, it was much wider than Soviet trains at the time. He planned on widening the rails from 1.524 meters, which was the standard distance for Soviet tracks set in the 19th century, to 4.5 meters. For reference, the tracks in New South Wales, which were modernized in 2012, almost 70 years after Moralevich's idea, are precisely 4.5 meters apart. This is just a testament to how ahead of his time he was.\n\nBy widening the tracks, the freight cars could be increased threefold in width, height, and length, while the cargo capacity of each car could increase by approximately 27 times. As Moralevich puts it, a single car could, for example, carry 1600 tons of wheat instead of the standard 60 tons from Moscow to Vladivostok.\n\nOne of the biggest issues behind this revolution was the source of power—what could power monstrously large trains Moralevich planned on building? He found the answer to that in nuclear energy.\n\nIn his detailed breakdown of his nuclear-powered train design, he hypothesized that a small nuclear reactor could develop thermal power of about 30 thousand kilowatts. This would translate to between 5000 and 7500 horsepower, which could operate for months before replacing. Moralevich also wrote about nuclear batteries, claiming that they would be able to power the electric motors for an entire decade before needing replacing.\n\nThese batteries are similar to nuclear reactors as they also generate electricity from nuclear energy, but there are a few major differences between the two. For one, a battery doesn't rely on a controlled chain reaction to release heat. Instead, they generate heat, and in turn electricity, through the decay of radioactive particles.\n\nThe downside of this method of energy generation lies in the scale, as nuclear batteries cannot hold a candle to nuclear reactors in terms of sheer power. However, this is just perfect for a nuclear train, at least in theory.\n\nPerhaps the biggest crux of the nuclear train conundrum, and this is something we'll discuss in detail later, is its relative safety. All scientists agree that if you put a nuclear reactor in a train, you need to build a shield around it to prevent a nuclear disaster. This shield needs to be massive, weighing hundreds of tons, which means that you need even more power to push the train onward. You also need a team of experts controlling and maintaining the radioactive core at all times.\n\nThis wouldn't be necessary with a nuclear battery, as it's passively controlled with the process of decay dictating power output, and generally less likely to cause a disaster. Even in the case of a crash, the radioactive energy released would be incomparable to the release from a nuclear reactor.\n\nBecause of this, nuclear batteries have been in use for decades in various fields. They're common in satellites, moon landers—with *Perseverance* Mars rover using them—and they were even used in pacemakers before lithium-powered pacemakers were invented in the late 1980s. Yes, nuclear batteries were deemed safe enough to install them in human bodies, and Moralevich claimed they could power trains decades before that!\n\nWhether they'd rely on a nuclear reactor or nuclear batteries, the engines of the Soviet atomic train could, in theory, exceed speeds of 200 kilometers per hour, but the train wouldn't sway thanks to wider tracks. Moralevich's atomic train could take cargo and passengers from Moscow to Saint Petersburg, known as Leningrad back in the day, within four hours, which is roughly how long the trip takes today! Despite the detailed and sensible design, Moralevich's train was never built, and this seems to be the end result of every single nuclear train blueprint.\n\nWest Germany had a similar idea, one based on Nazi Germany developments of nuclear power submarines in the 1940s. In fact, the German manufacturing company Krauss-Maffei seriously considered developing a 35 kilometer-long nuclear train in the fifties, but ultimately abandoned the project.\n\nThe closest the idea ever got from blueprint to reality was for military means. Both the US Army and the Soviets had the idea for an all-terrain, nuclear-powered land train.\n\nFor the Americans, it was a purely logistical solution. The Army was actively looking for ways to exploit nuclear energy, and aside from making more nuclear bombs, logistics was an area that showed room for improvement.\n\nThe Army operated many remote bases, some of which were, and still are, located in meteorologically hazardous areas. All army bases need to move fuel, water, food, supplies, and personnel back and forth, and the difficulty of logistical operations increases with the distance between the base and the closest populated area. With its very recent experience of World War II and first-hand accounts of just how easily fuel burns during a war, the Army recognized the importance of a transport solution that minimized fuel consumption.\n\nCue, the land train.\n\nThis train would consist of multiple cars that were prepared for both on-road and off-road trips. Unlike a traditional train, it wouldn't need tracks to move, and it would save on fuel at the same time because it would be powered by a small nuclear reactor. In contrast to the X-12, this land train was small and light, so it wouldn't need as nearly as much power, opening the door for a tiny nuclear reactor, or even nuclear batteries.\n\nThe Army actually designed a diesel-powered prototype, and followed it up with a nuclear prototype, but neither ever made it out of the testing phase.\n\nAlthough the lightweight and high-powered design allowed for ludicrous amounts of cargo to be transported with virtually no fuel consumption, the design was, for reasons unknown, never approved for production.\n\nThe Soviets, however, went a step further. Although part of the reason was logistical, they also wanted to establish presence in the Far North, and transporting supplies to extremely cold environments was painfully difficult at the time.\n\nAn idea was proposed by the Soviet Minister of Medium Machine Building Yefim Slavsky—the same guy who insisted upon the development of the Tsar Bomba, the most powerful thermonuclear weapon known to man, and yes, one of the men responsible for the Chernobyl disaster.\n\nIn 1955, he suggested the development of a mobile nuclear power plant that could supply remote military and civilian facilities with electricity. The self-propelled nuclear train would approach a settlement, provide it with power for a few years, and move on to another place. It was certainly a more viable solution than building an on-site power plant in a permafrost desert.\n\nJust two years later, the first design of the TES-3 was ready. Originally conceived as a nuclear train, the rail-dependent design was quickly discarded for tank tracks. Although the land cars would still be attached to one another with cables and pipes, the engineers realized that the TES-3 would be too dependent on the railway—not only its reach, but its state as well—so they opted for an off-road design.\n\nThe bodies of the cars were described as \"wagon-type\" in the original plans, but they replaced the train chassis with an elongated heavy-tank chassis. This was poetic as the TES-3 was built in Saint Petersburg's Kirov Plant—the same factory that pushed KV-1 tanks off its production line during the Second World War.\n\nIn 1961, this train-tank hybrid became the world's first mobile land-based nuclear power plant, and the presence of Yuriy Gagarin, the first man in space, at the unveiling speaks to the magnitude of this achievement for Soviet nuclear engineering.\n\nDuring its testing phase, which started in 1961 and ended in 1965, the TES-3 operated for 13,000 hours without any accidents. Despite the favorable testing results, the TES-3 never actually voyaged to the Far North and fulfilled its purpose. The entire project was scrapped, the reactor was shut down, and the components of the nuclear land train are now collecting dust at the Obninsk Institute of Physics and Power Engineering.\n\nThe Soviets, however, had another idea, and this one actually came to fruition. To hide their intercontinental ballistic missiles from American spy planes, Soviet leadership came up with a plan to load them on a train. The train would cruise on the USSR's endless railways in random patterns, making it borderline impossible for the spy planes to spot it. The ICBMs would only be launched as a retaliatory measure, if the USSR found itself under attack. It was the Soviet way of saying \"If I am going to hell, I'm taking you with me.\"\n\nThe missiles weighed more than 104 metric tons, and to move them around, alongside the added weight of the train, operating modules, facilities, and crew, you would need a whole lot of fuel. Naturally, the idea of powering the train with a nuclear reactor came into play. It was, after all, tested with great success with the TES-3, but for reasons unknown, the Soviets opted for a traditional power source. The RT-23 Molodets, as is the official name of the ICBM system, stepped into service in 1987, but the only 'nuclear' parts of the system were the warheads.\n\nThat was the last the world has heard of atomic trains for a while. Then, in 2008, a Mr. William Gregory Taylor filed a patent proposition with the US Patent and Trademark Office. In his proposition, he described the pairing of an on-board nuclear reactor with a magnetically levitated vehicle, which was the world's first, and so far last mention of a nuclear maglev.\n\nThe final mention of a nuclear train, at least at the time of recording, was in 2011. Then, the vice president of Russian Railways said that they would present a nuclear train by the end of the year. The 11-wagon train was supposed to be powered by a small nuclear reactor, and in its initial stage, it would only be a scientific exhibition.\n\nThe train, however, never even reached the exhibition stage, and it's completely unknown what happened to it.\n\nThere seems to be an emerging pattern with nuclear trains. They're most often designed, and don't move an inch further, or in some cases, a prototype is built but never mass-produced.\n\nWhy is that? Why is it that there were so many ideas, designs, and even prototypes of nuclear-powered trains that never made it out the testing phase, and in some cases, never left the drawing board?\n\n## Why The Nuclear Train Never Left The Station\n\nThe biggest selling points of a nuclear train are its fuel efficiency and low carbon emissions, but if we look past that, we can see that the idea is plagued by a plethora of logistic problems and safety concerns.\n\nThe first of many logistical issues is the price of a nuclear train. The X-12 would cost $1.2 million dollars to build in 1954, which translates to about $14 million today. For comparison, you would need to cash out around $5 million dollars to build a passenger locomotive today, which means that you could build almost three traditional locomotives for the price of one X-12.\n\nThis is already a major financial setback for the project, but Dr. Borst insisted that his project, the X-12, would be financially feasible—paying for itself down the line. Whether that's truly the case is irrelevant now, though, because there are so many other problems that stopped this idea from becoming reality.\n\nOne of those problems presents itself in the form of maintenance. Although traditional trains need regular maintenance, an atomic train would require a team of experts regularly checking the core. This on-board team would also need to be present at all times to react in case the core starts heating up too much, and since nuclear physicists don't exactly grow on trees, their salaries would significantly impact the cost of running the train.\n\nRadioactive waste management would present another massive issue. The good thing about, according to the World Nuclear Association, is that radioactive waste is not as hazardous nor hard to manage in comparison to other types of toxic waste as people think. On top of that, the sheer amount of it is unimpressive in comparison to other electricity generation technologies. Once we look past that, though, you do need to store it for about 100 thousand years, and time isn't your only enemy in this regard. Space would be another issue, especially if an entire fleet of nuclear trains is built. They would leave tons of radioactive waste as they chugged along the world's railways, requiring storage room that doesn't come for free. Radioactive waste would thus present another box to check on a nuclear train's to-do list, and it would require further investment in the form of transport and storage.\n\nHowever, perhaps the most common argument proposed against nuclear trains is their redundancy. We already have nuclear trains…sort of.\n\nIn 2013, the UK agreed to rely on EDF Energy's nuclear power plants to electrify its trains. Network Rail is, after all, the UK's largest power consumer, and in 2024, only 38% of it was electrified. Railway electrification is actually one of the biggest infrastructural projects in the UK at the moment, and when it's finished, trains could, in theory, all be powered by electricity transferred from nuclear power plants. This would be a great step towards greening up the entire country, and it would play a huge part in the country's goal to reach net zero greenhouse gas emissions by the year 2050.\n\nUnfortunately for nuclear trains, it is also a great example as to why it makes no sense to load up a tiny nuclear reactor on a locomotive. We already have a very efficient way of moving electricity from nuclear plants and powering trains with it. Shrinking the power source and placing it on the train it's supposed to power would take a lot of effort and a lot of man hours, while achieving essentially the same results. It would also put a lot of people at risk, which brings us to the most damning argument against nuclear trains.\n\nSafety and security of nuclear power have been the critical talking points on this matter ever since 1945, when the world first witnessed what that power can do when weaponized.\n\nIn terms of safety, we're talking about moving a nuclear reactor through cities, towns, counties, and even countries. Crossing jurisdictions with the most powerful source of energy known to man on board is bound to cause a legal catastrophe, and it's quite unlikely that every country would welcome a nuclear train with open arms—and with good reason.\n\nThere is a clear sense of public paranoia surrounding nuclear energy. The Chernobyl disaster is, in fact, one of the main reasons why the Soviets abandoned most of their nuclear projects, and a more recent incident, one pertaining specifically to trains, proposes an even stronger argument against nuclear trains.\n\nIn June of 2002, a train transporting a nuclear flask—a type of shipping container used for active nuclear materials—collided with a lorry at a crossing in Kent. Emergency teams immediately went out and, to everyone's relief, they found the flask to be empty. Despite that, anti-nuclear campaigners rightfully called out the safety of this type of transport, the most important question being \"What if the flask had been full?\"\n\nThis is a perfectly reasonable argument, as it doesn't matter whether the locomotive is powered by a diesel engine or a nuclear reactor—the train can still crash.\n\nThe result of a radioactive leak caused by a train crash could be catastrophic, and the designers of atomic trains knew this, which is why the reactors in their designs are always protected. A valid solution, certainly, but it is at the same time digging the design into an even deeper financial hole.\n\nTaking the X-12 as an example, this locomotive would be powered by a small reactor core, measuring only 36 by 10 inches—certainly not something you'd call big. In order to protect the reactor, however, a ludicrously large safe would need to encase it. This safe would weigh about 200 tons, accounting for about 55% of the weight of the entire locomotive. Moralevich's train design had an even larger shield, one weighing between 500 and 600 tons.\n\nIn either case a massive chunk of energy created by the reactor would be wasted on moving the reactor's shield, which is an incredibly inefficient design. This massive drawback stems from the simple fact that we still cannot guarantee the absolute safety of nuclear reactors—no matter how small they are. However, even if these shields could keep the reactors perfectly safe, and even if the idea for a nuclear train would pass legislation and it somehow attracted investors, there is yet another glaring issue standing in its way to reality—terrorism.\n\nNo country will risk the safety of its citizens just to lower its railway's carbon footprint. Nuclear terrorism is a security threat of such magnitude that the United Nations developed a specialized program dedicated just to the prevention of the development of nuclear weapons of mass destruction by terrorists. The reason security experts are so committed toward keeping nuclear materials out of terrorists' hands is because, frankly, a dirty bomb is not that difficult to build.\n\nIn fact, a US Senator once invited representatives of several weapon laboratories to discuss nuclear weapons, and asked them if they could build an off-the-shelf nuclear device. One of the laboratories reached out a few months later and simply told him \"We built one.\" That Senator's name was Joe Biden, and he told this story in 2004, long before he'd become vice-president. In that position, he influenced Obama's policies by shedding light on the importance of keeping nuclear weapons out of terrorist hands, which he considered one of the most important duties of that administration.\n\nBuilding a nuclear device is not a problem—getting your hands on nuclear material is.\n\nIf you were to build a nuclear train, you would have to keep a security team on board at all times. Security would have to go past that, however. Screening for threats would have to be done beforehand, as it's almost a guarantee that there would be someone interested in grabbing the nuclear reactor.\n\nThere is no shield to mitigate this threat—a mobile nuclear reactor would present such a weak spot, such a vulnerability, that every world leader would be rightfully concerned about it.\n\nEven if we could somehow bypass all other drawbacks of a nuclear train design, this vulnerability alone strikes the final nail in the atomic train's coffin, which is why it is highly unlikely that we will ever get to see one.\n\nWould it work? Yes.\n\nWould it pay off? Strictly environmentally speaking—yes.\n\nBut at the same time, it would develop into a financial black hole, and present a massive safety and security threat.\n\nWe already possess methods that allow us to power trains through nuclear energy, and when you draw the line, the risk to benefit ratio of those technologies fares far better than that of nuclear trains, which is why this idea will likely stay on paper forever.\n\n## Key Takeaways\n\n- Nuclear trains were envisioned in the mid-20th century to improve fuel efficiency and reduce carbon footprints.\n- Several detailed designs and prototypes were created, but none progressed beyond testing due to logistical and safety concerns.\n- The high cost of building and maintaining nuclear trains, along with the need for expert teams, made them financially unfeasible.\n- Safety and security risks, including the potential for radioactive leaks and terrorist threats, were major obstacles.\n- Existing methods of powering trains with electricity from nuclear plants are more efficient and safer than on-board nuclear reactors.\n\n## Frequently Asked Questions\n\n### What was the X-12?\n\nThe X-12 was the world's first design for a nuclear locomotive, proposed by Dr. Lyle Borst. It was designed to travel around the world twice before its first refueling.\n\n### What were the main advantages of nuclear trains?\n\nNuclear trains were seen as advantageous due to their potential for long durations between refueling, reduced reliance on power lines, and lower carbon emissions.\n\n### Why were nuclear trains not developed despite initial enthusiasm?\n\nNuclear trains were not developed due to various logistical issues, safety concerns, high costs, and the redundancy of the concept given existing nuclear power infrastructure.\n\n### What was the TES-3?\n\nThe TES-3 was the world's first mobile land-based nuclear power plant, developed by the Soviets. It was designed to supply remote military and civilian facilities with electricity.\n\n### What was the RT-23 Molodets?\n\nThe RT-23 Molodets was a Soviet ICBM system that used trains to move intercontinental ballistic missiles around the USSR's railway network to avoid detection by American spy planes.\n\n### What were the main safety concerns with nuclear trains?\n\nThe main safety concerns with nuclear trains included the risk of radioactive leaks in case of accidents, the need for massive protective shields, and the vulnerability to terrorism.\n\n### What was the cost of building the X-12?\n\nThe X-12 was estimated to cost $1.2 million dollars to build in 1954, which translates to about $14 million today.\n\n### What was the proposed use of nuclear batteries in nuclear trains?\n\nNuclear batteries were proposed as an alternative to nuclear reactors in trains. They generate electricity through the decay of radioactive particles and are safer and less powerful than reactors.\n\n### What was the proposed design by Yuriy Moralevich?\n\nYuriy Moralevich proposed a double-decker nuclear train with wider tracks, allowing for significantly increased cargo capacity. The train was designed to be powered by a small nuclear reactor or nuclear batteries.\n\n### What was the UK's approach to using nuclear power for trains?\n\nThe UK agreed to rely on EDF Energy's nuclear power plants to electrify its trains, making it one of the largest infrastructural projects in the UK aimed at reducing greenhouse gas emissions.\n\n## Sources\n\n- [Original MegaProjects video: Nuclear Trains: Why We Can't Have These...](https://www.youtube.com/watch?v=J4Pqo6PskpQ)\n- [Hero image source](https://upload.wikimedia.org/wikipedia/commons/f/fb/2025_BYD_Shark_6_front.jpg) by LuvsMG481 / openverse, by-sa.\n\n## Related Coverage" url: https://megaprojects.pub/article/nuclear-trains-why-we-cant-have-these.md canonical: https://megaprojects.pub/article/nuclear-trains-why-we-cant-have-these datePublished: 2026-07-02 dateModified: 2026-07-02 author: - name: Simon Whistler url: https://megaprojects.pub/author/simon-whistler publisher: MegaProjects image: "https://media.megaprojects.pub/cdn-cgi/image/width=600,height=338,fit=cover,quality=80,format=auto/articles/J4Pqo6PskpQ/hero.jpg" type: NewsArticle contentHash: 325553645411d2a09ac1664b28e86b6a21e33169a055add85962c9bb62121e63 tokens: 6833 summaryUrl: https://megaprojects.pub/article/nuclear-trains-why-we-cant-have-these.md.summary.md --- The idea of a nuclear train was one of many engineering projects that was born out of the mid-20th century nuclear boom. This period paved the way for hundreds of theoretical ways scientists could use nuclear power to improve our everyday lives, and transport made up a large part of that list. Nuclear powered aircraft, submarines, cars, aircraft carriers, and trains were all seen as very realistic possibilities, but only some of them became reality. Nuclear trains, for one, were seen as an easy enough upgrade from traditional locomotives, one that would save on fuel and lower the entire planet's carbon footprint. There were, in fact, several detailed designs, some of which were even patented, and even military projects with government backing. However, despite the vehement enthusiasm surrounding the idea, after careful analysis, it was concluded in every single case that developing a nuclear locomotive simply made no sense. Here's why. ## Where It All Began In the 1950s, nuclear power was in its infancy. Although some scientists very accurately predicted its capabilities, nuclear power was, at the time, a new field of exploration. As it started becoming more and more apparent that humans have just stumbled upon a source of energy so powerful it could seemingly solve all the world's problems, brand new engineering ideas started surfacing left, right, and center. All of a sudden, 'nuclear' was the one size fits all solution for all the world's problems, and trains were just another entry on the list of things we could improve with nuclear energy. This idea is, more than anything, a product of its time. In theory, nuclear trains could entirely replace traditional locomotives that have to stay close to power lines or regularly stop to take on coal or oil. A nuclear train could keep chugging down the rails for months, or maybe even years before refueling. In fact, the X-12, the world's first design for a nuclear locomotive, could have, in theory, traveled around the world twice before its first refueling. We, of course, can't know this for certain, as the X-12 was never built, but the man behind its design, Dr. Lyle Borst, said that in an interview with *Life* magazine. Aside from the astounding fuel efficiency, a nuclear train would also make power line maintenance much easier. Since it would operate completely independently, without any reliance on the electric grid, less time and fewer resources would have to be invested into maintenance. This would be especially useful in countries such as the United States and the USSR, which have hundreds of kilometers of train tracks dislocated far away from populated areas. A nuclear locomotive could do all of that while minimizing its carbon footprint. That, unfortunately, wouldn't have been quite the selling point in the 1950s as it is today as the public wasn't as informed about the potential impact of rising levels of carbon dioxide. It was, however, important to physicists, who were well aware of how important the lowering of our collective carbon footprint could become. With all of these positives, it's only natural that the two greatest world powers at the time, the United States and the USSR, showed affinity toward the idea. ## Designs and Real Life Applications There were dozens of atomic train ideas and proposals around the entire world at the time, but the first to present an actual design with feasibility calculations was the aforementioned Dr. Borst of the University of Utah. We've already done a deep dive on Dr. Borst's X-12 if you're interested in a detailed breakdown, but in short, the X-12 was a breathtaking idea at the time. The locomotive would be powered by an atomic reactor which would split uranium atoms, release tremendous amounts of energy in the form of heat, and generate steam by boiling water. The steam would pass through a pressurizer and rotate turbines, which would be connected to generators, converting the mechanical energy into electrical. This is, in essence, how all nuclear power plants work, only this generator would be small enough to fit in a locomotive. The massive electric motors would produce 7000 horsepower and roll the train onwards. The X-12 would predominantly transport cargo, but it could, over time, become a passenger train too. The Soviets had a similar idea, albeit two years after the Americans. In 1956, the Ministry of Transport kickstarted a campaign for several atomic train designs. It's no surprise that the Soviets were particularly interested in nuclear-powered trains—they had one of the largest railway networks in the world at the time, and the idea of saving on fuel was certainly tempting. One of those designs was made by the forgotten Soviet engineer Yuriy Moralevich, who also happens to be one of the engineers behind the world's first nuclear-powered icebreaker, and the world's first nuclear-power ship in general—*The Lenin*. Moralevich planned to completely revolutionize the Soviet railway system. For one, the train he had designed was not only a double-decker, it was much wider than Soviet trains at the time. He planned on widening the rails from 1.524 meters, which was the standard distance for Soviet tracks set in the 19th century, to 4.5 meters. For reference, the tracks in New South Wales, which were modernized in 2012, almost 70 years after Moralevich's idea, are precisely 4.5 meters apart. This is just a testament to how ahead of his time he was. By widening the tracks, the freight cars could be increased threefold in width, height, and length, while the cargo capacity of each car could increase by approximately 27 times. As Moralevich puts it, a single car could, for example, carry 1600 tons of wheat instead of the standard 60 tons from Moscow to Vladivostok. One of the biggest issues behind this revolution was the source of power—what could power monstrously large trains Moralevich planned on building? He found the answer to that in nuclear energy. In his detailed breakdown of his nuclear-powered train design, he hypothesized that a small nuclear reactor could develop thermal power of about 30 thousand kilowatts. This would translate to between 5000 and 7500 horsepower, which could operate for months before replacing. Moralevich also wrote about nuclear batteries, claiming that they would be able to power the electric motors for an entire decade before needing replacing. These batteries are similar to nuclear reactors as they also generate electricity from nuclear energy, but there are a few major differences between the two. For one, a battery doesn't rely on a controlled chain reaction to release heat. Instead, they generate heat, and in turn electricity, through the decay of radioactive particles. The downside of this method of energy generation lies in the scale, as nuclear batteries cannot hold a candle to nuclear reactors in terms of sheer power. However, this is just perfect for a nuclear train, at least in theory. Perhaps the biggest crux of the nuclear train conundrum, and this is something we'll discuss in detail later, is its relative safety. All scientists agree that if you put a nuclear reactor in a train, you need to build a shield around it to prevent a nuclear disaster. This shield needs to be massive, weighing hundreds of tons, which means that you need even more power to push the train onward. You also need a team of experts controlling and maintaining the radioactive core at all times. This wouldn't be necessary with a nuclear battery, as it's passively controlled with the process of decay dictating power output, and generally less likely to cause a disaster. Even in the case of a crash, the radioactive energy released would be incomparable to the release from a nuclear reactor. Because of this, nuclear batteries have been in use for decades in various fields. They're common in satellites, moon landers—with *Perseverance* Mars rover using them—and they were even used in pacemakers before lithium-powered pacemakers were invented in the late 1980s. Yes, nuclear batteries were deemed safe enough to install them in human bodies, and Moralevich claimed they could power trains decades before that! Whether they'd rely on a nuclear reactor or nuclear batteries, the engines of the Soviet atomic train could, in theory, exceed speeds of 200 kilometers per hour, but the train wouldn't sway thanks to wider tracks. Moralevich's atomic train could take cargo and passengers from Moscow to Saint Petersburg, known as Leningrad back in the day, within four hours, which is roughly how long the trip takes today! Despite the detailed and sensible design, Moralevich's train was never built, and this seems to be the end result of every single nuclear train blueprint. West Germany had a similar idea, one based on Nazi Germany developments of nuclear power submarines in the 1940s. In fact, the German manufacturing company Krauss-Maffei seriously considered developing a 35 kilometer-long nuclear train in the fifties, but ultimately abandoned the project. The closest the idea ever got from blueprint to reality was for military means. Both the US Army and the Soviets had the idea for an all-terrain, nuclear-powered land train. For the Americans, it was a purely logistical solution. The Army was actively looking for ways to exploit nuclear energy, and aside from making more nuclear bombs, logistics was an area that showed room for improvement. The Army operated many remote bases, some of which were, and still are, located in meteorologically hazardous areas. All army bases need to move fuel, water, food, supplies, and personnel back and forth, and the difficulty of logistical operations increases with the distance between the base and the closest populated area. With its very recent experience of World War II and first-hand accounts of just how easily fuel burns during a war, the Army recognized the importance of a transport solution that minimized fuel consumption. Cue, the land train. This train would consist of multiple cars that were prepared for both on-road and off-road trips. Unlike a traditional train, it wouldn't need tracks to move, and it would save on fuel at the same time because it would be powered by a small nuclear reactor. In contrast to the X-12, this land train was small and light, so it wouldn't need as nearly as much power, opening the door for a tiny nuclear reactor, or even nuclear batteries. The Army actually designed a diesel-powered prototype, and followed it up with a nuclear prototype, but neither ever made it out of the testing phase. Although the lightweight and high-powered design allowed for ludicrous amounts of cargo to be transported with virtually no fuel consumption, the design was, for reasons unknown, never approved for production. The Soviets, however, went a step further. Although part of the reason was logistical, they also wanted to establish presence in the Far North, and transporting supplies to extremely cold environments was painfully difficult at the time. An idea was proposed by the Soviet Minister of Medium Machine Building Yefim Slavsky—the same guy who insisted upon the development of the Tsar Bomba, the most powerful thermonuclear weapon known to man, and yes, one of the men responsible for the Chernobyl disaster. In 1955, he suggested the development of a mobile nuclear power plant that could supply remote military and civilian facilities with electricity. The self-propelled nuclear train would approach a settlement, provide it with power for a few years, and move on to another place. It was certainly a more viable solution than building an on-site power plant in a permafrost desert. Just two years later, the first design of the TES-3 was ready. Originally conceived as a nuclear train, the rail-dependent design was quickly discarded for tank tracks. Although the land cars would still be attached to one another with cables and pipes, the engineers realized that the TES-3 would be too dependent on the railway—not only its reach, but its state as well—so they opted for an off-road design. The bodies of the cars were described as "wagon-type" in the original plans, but they replaced the train chassis with an elongated heavy-tank chassis. This was poetic as the TES-3 was built in Saint Petersburg's Kirov Plant—the same factory that pushed KV-1 tanks off its production line during the Second World War. In 1961, this train-tank hybrid became the world's first mobile land-based nuclear power plant, and the presence of Yuriy Gagarin, the first man in space, at the unveiling speaks to the magnitude of this achievement for Soviet nuclear engineering. During its testing phase, which started in 1961 and ended in 1965, the TES-3 operated for 13,000 hours without any accidents. Despite the favorable testing results, the TES-3 never actually voyaged to the Far North and fulfilled its purpose. The entire project was scrapped, the reactor was shut down, and the components of the nuclear land train are now collecting dust at the Obninsk Institute of Physics and Power Engineering. The Soviets, however, had another idea, and this one actually came to fruition. To hide their intercontinental ballistic missiles from American spy planes, Soviet leadership came up with a plan to load them on a train. The train would cruise on the USSR's endless railways in random patterns, making it borderline impossible for the spy planes to spot it. The ICBMs would only be launched as a retaliatory measure, if the USSR found itself under attack. It was the Soviet way of saying "If I am going to hell, I'm taking you with me." The missiles weighed more than 104 metric tons, and to move them around, alongside the added weight of the train, operating modules, facilities, and crew, you would need a whole lot of fuel. Naturally, the idea of powering the train with a nuclear reactor came into play. It was, after all, tested with great success with the TES-3, but for reasons unknown, the Soviets opted for a traditional power source. The RT-23 Molodets, as is the official name of the ICBM system, stepped into service in 1987, but the only 'nuclear' parts of the system were the warheads. That was the last the world has heard of atomic trains for a while. Then, in 2008, a Mr. William Gregory Taylor filed a patent proposition with the US Patent and Trademark Office. In his proposition, he described the pairing of an on-board nuclear reactor with a magnetically levitated vehicle, which was the world's first, and so far last mention of a nuclear maglev. The final mention of a nuclear train, at least at the time of recording, was in 2011. Then, the vice president of Russian Railways said that they would present a nuclear train by the end of the year. The 11-wagon train was supposed to be powered by a small nuclear reactor, and in its initial stage, it would only be a scientific exhibition. The train, however, never even reached the exhibition stage, and it's completely unknown what happened to it. There seems to be an emerging pattern with nuclear trains. They're most often designed, and don't move an inch further, or in some cases, a prototype is built but never mass-produced. Why is that? Why is it that there were so many ideas, designs, and even prototypes of nuclear-powered trains that never made it out the testing phase, and in some cases, never left the drawing board? ## Why The Nuclear Train Never Left The Station The biggest selling points of a nuclear train are its fuel efficiency and low carbon emissions, but if we look past that, we can see that the idea is plagued by a plethora of logistic problems and safety concerns. The first of many logistical issues is the price of a nuclear train. The X-12 would cost $1.2 million dollars to build in 1954, which translates to about $14 million today. For comparison, you would need to cash out around $5 million dollars to build a passenger locomotive today, which means that you could build almost three traditional locomotives for the price of one X-12. This is already a major financial setback for the project, but Dr. Borst insisted that his project, the X-12, would be financially feasible—paying for itself down the line. Whether that's truly the case is irrelevant now, though, because there are so many other problems that stopped this idea from becoming reality. One of those problems presents itself in the form of maintenance. Although traditional trains need regular maintenance, an atomic train would require a team of experts regularly checking the core. This on-board team would also need to be present at all times to react in case the core starts heating up too much, and since nuclear physicists don't exactly grow on trees, their salaries would significantly impact the cost of running the train. Radioactive waste management would present another massive issue. The good thing about, according to the World Nuclear Association, is that radioactive waste is not as hazardous nor hard to manage in comparison to other types of toxic waste as people think. On top of that, the sheer amount of it is unimpressive in comparison to other electricity generation technologies. Once we look past that, though, you do need to store it for about 100 thousand years, and time isn't your only enemy in this regard. Space would be another issue, especially if an entire fleet of nuclear trains is built. They would leave tons of radioactive waste as they chugged along the world's railways, requiring storage room that doesn't come for free. Radioactive waste would thus present another box to check on a nuclear train's to-do list, and it would require further investment in the form of transport and storage. However, perhaps the most common argument proposed against nuclear trains is their redundancy. We already have nuclear trains…sort of. In 2013, the UK agreed to rely on EDF Energy's nuclear power plants to electrify its trains. Network Rail is, after all, the UK's largest power consumer, and in 2024, only 38% of it was electrified. Railway electrification is actually one of the biggest infrastructural projects in the UK at the moment, and when it's finished, trains could, in theory, all be powered by electricity transferred from nuclear power plants. This would be a great step towards greening up the entire country, and it would play a huge part in the country's goal to reach net zero greenhouse gas emissions by the year 2050. Unfortunately for nuclear trains, it is also a great example as to why it makes no sense to load up a tiny nuclear reactor on a locomotive. We already have a very efficient way of moving electricity from nuclear plants and powering trains with it. Shrinking the power source and placing it on the train it's supposed to power would take a lot of effort and a lot of man hours, while achieving essentially the same results. It would also put a lot of people at risk, which brings us to the most damning argument against nuclear trains. Safety and security of nuclear power have been the critical talking points on this matter ever since 1945, when the world first witnessed what that power can do when weaponized. In terms of safety, we're talking about moving a nuclear reactor through cities, towns, counties, and even countries. Crossing jurisdictions with the most powerful source of energy known to man on board is bound to cause a legal catastrophe, and it's quite unlikely that every country would welcome a nuclear train with open arms—and with good reason. There is a clear sense of public paranoia surrounding nuclear energy. The Chernobyl disaster is, in fact, one of the main reasons why the Soviets abandoned most of their nuclear projects, and a more recent incident, one pertaining specifically to trains, proposes an even stronger argument against nuclear trains. In June of 2002, a train transporting a nuclear flask—a type of shipping container used for active nuclear materials—collided with a lorry at a crossing in Kent. Emergency teams immediately went out and, to everyone's relief, they found the flask to be empty. Despite that, anti-nuclear campaigners rightfully called out the safety of this type of transport, the most important question being "What if the flask had been full?" This is a perfectly reasonable argument, as it doesn't matter whether the locomotive is powered by a diesel engine or a nuclear reactor—the train can still crash. The result of a radioactive leak caused by a train crash could be catastrophic, and the designers of atomic trains knew this, which is why the reactors in their designs are always protected. A valid solution, certainly, but it is at the same time digging the design into an even deeper financial hole. Taking the X-12 as an example, this locomotive would be powered by a small reactor core, measuring only 36 by 10 inches—certainly not something you'd call big. In order to protect the reactor, however, a ludicrously large safe would need to encase it. This safe would weigh about 200 tons, accounting for about 55% of the weight of the entire locomotive. Moralevich's train design had an even larger shield, one weighing between 500 and 600 tons. In either case a massive chunk of energy created by the reactor would be wasted on moving the reactor's shield, which is an incredibly inefficient design. This massive drawback stems from the simple fact that we still cannot guarantee the absolute safety of nuclear reactors—no matter how small they are. However, even if these shields could keep the reactors perfectly safe, and even if the idea for a nuclear train would pass legislation and it somehow attracted investors, there is yet another glaring issue standing in its way to reality—terrorism. No country will risk the safety of its citizens just to lower its railway's carbon footprint. Nuclear terrorism is a security threat of such magnitude that the United Nations developed a specialized program dedicated just to the prevention of the development of nuclear weapons of mass destruction by terrorists. The reason security experts are so committed toward keeping nuclear materials out of terrorists' hands is because, frankly, a dirty bomb is not that difficult to build. In fact, a US Senator once invited representatives of several weapon laboratories to discuss nuclear weapons, and asked them if they could build an off-the-shelf nuclear device. One of the laboratories reached out a few months later and simply told him "We built one." That Senator's name was Joe Biden, and he told this story in 2004, long before he'd become vice-president. In that position, he influenced Obama's policies by shedding light on the importance of keeping nuclear weapons out of terrorist hands, which he considered one of the most important duties of that administration. Building a nuclear device is not a problem—getting your hands on nuclear material is. If you were to build a nuclear train, you would have to keep a security team on board at all times. Security would have to go past that, however. Screening for threats would have to be done beforehand, as it's almost a guarantee that there would be someone interested in grabbing the nuclear reactor. There is no shield to mitigate this threat—a mobile nuclear reactor would present such a weak spot, such a vulnerability, that every world leader would be rightfully concerned about it. Even if we could somehow bypass all other drawbacks of a nuclear train design, this vulnerability alone strikes the final nail in the atomic train's coffin, which is why it is highly unlikely that we will ever get to see one. Would it work? Yes. Would it pay off? Strictly environmentally speaking—yes. But at the same time, it would develop into a financial black hole, and present a massive safety and security threat. We already possess methods that allow us to power trains through nuclear energy, and when you draw the line, the risk to benefit ratio of those technologies fares far better than that of nuclear trains, which is why this idea will likely stay on paper forever. ## Key Takeaways - Nuclear trains were envisioned in the mid-20th century to improve fuel efficiency and reduce carbon footprints. - Several detailed designs and prototypes were created, but none progressed beyond testing due to logistical and safety concerns. - The high cost of building and maintaining nuclear trains, along with the need for expert teams, made them financially unfeasible. - Safety and security risks, including the potential for radioactive leaks and terrorist threats, were major obstacles. - Existing methods of powering trains with electricity from nuclear plants are more efficient and safer than on-board nuclear reactors. ## Frequently Asked Questions ### What was the X-12? The X-12 was the world's first design for a nuclear locomotive, proposed by Dr. Lyle Borst. It was designed to travel around the world twice before its first refueling. ### What were the main advantages of nuclear trains? Nuclear trains were seen as advantageous due to their potential for long durations between refueling, reduced reliance on power lines, and lower carbon emissions. ### Why were nuclear trains not developed despite initial enthusiasm? Nuclear trains were not developed due to various logistical issues, safety concerns, high costs, and the redundancy of the concept given existing nuclear power infrastructure. ### What was the TES-3? The TES-3 was the world's first mobile land-based nuclear power plant, developed by the Soviets. It was designed to supply remote military and civilian facilities with electricity. ### What was the RT-23 Molodets? The RT-23 Molodets was a Soviet ICBM system that used trains to move intercontinental ballistic missiles around the USSR's railway network to avoid detection by American spy planes. ### What were the main safety concerns with nuclear trains? The main safety concerns with nuclear trains included the risk of radioactive leaks in case of accidents, the need for massive protective shields, and the vulnerability to terrorism. ### What was the cost of building the X-12? The X-12 was estimated to cost $1.2 million dollars to build in 1954, which translates to about $14 million today. ### What was the proposed use of nuclear batteries in nuclear trains? Nuclear batteries were proposed as an alternative to nuclear reactors in trains. They generate electricity through the decay of radioactive particles and are safer and less powerful than reactors. ### What was the proposed design by Yuriy Moralevich? Yuriy Moralevich proposed a double-decker nuclear train with wider tracks, allowing for significantly increased cargo capacity. The train was designed to be powered by a small nuclear reactor or nuclear batteries. ### What was the UK's approach to using nuclear power for trains? The UK agreed to rely on EDF Energy's nuclear power plants to electrify its trains, making it one of the largest infrastructural projects in the UK aimed at reducing greenhouse gas emissions. ## Sources - [Original MegaProjects video: Nuclear Trains: Why We Can't Have These...](https://www.youtube.com/watch?v=J4Pqo6PskpQ) - [Hero image source](https://upload.wikimedia.org/wikipedia/commons/f/fb/2025_BYD_Shark_6_front.jpg) by LuvsMG481 / openverse, by-sa. ## Related Coverage