Bringing the Railway to Daming

The video continues with incredibly high-tech visuals that exceed everyone's expectations.

"Similar technologies will not only revolutionize speed, but also various fields. From artificial hearts to artificial satellites... So, what exactly is magnetic levitation? How does it achieve all this? And what kind of future will it lead us to?"

"To answer these questions, we first need to leave the Earth's surface!"

Thus, the video transitions from the first chapter, "Magnetic Levitation, More Than Just Flight," to the second chapter, "Goodbye, Earth."

"For traditional trains, friction is their lifelong enemy. If the friction is too high, the resistance and wear will be greater; if it is too low, the wheels will slip (making it difficult to move forward)."

"This determines the speed limit of traditional trains, which is usually no more than 500 kilometers per hour. So what can be done?"

"Let's just leave the ground and completely get rid of friction!"

The video uses animation to show objects leaving the ground as if they were in a vacuum, without any friction.

At this moment, not only Lao Zhu and Zhu Biao watched intently, but even the young children who had just started school were watching without blinking, showing great interest in the science content in the video.

In fact, the princes and grandsons who had already studied some of the "Natural Science" curriculum were indeed able to understand the current content. This is why they listened with even greater focus.

The video shows a virtual laboratory that is common in later times, but to everyone else, it is a scene full of science fiction.

A woman began to explain the principle of "magnetic levitation" to the crowd.

"The most advanced technology often only requires the simplest principles. We all know that like poles of magnets repel each other and unlike poles attract each other. If we put magnets with the same magnetic poles on a train and its tracks, wouldn't the train be able to levitate?"

Listening to the woman's words and watching her conduct a simple magnetic pole experiment, the crowd reacted in various ways.

Xu Da and Tang He were thinking: We all know? But we don't.

Those who understood this simple scientific principle, such as Zhu Xiong Ying, had a sudden realization and thought: "Yes, why didn't I think of that before? If we put magnets with the same magnetic poles on the rails and the train respectively, wouldn't that make the train levitate?"
But those who are quick-witted have a vague feeling that things are not so simple.

really.

"However, the repulsive force of magnets is not stable; they will automatically switch to an attractive mode."

"So, the engineers decided to do the opposite!"

How can we do the opposite?
As Zhu Xiong Ying frowned in thought about this question, the video feed switched to a male narrator.

"This is the Shanghai Maglev Train Demonstration Line, the world's first commercially operated high-speed maglev train."

"Under its body is a C-shaped suspension frame that fits perfectly into a T-shaped track. By installing magnets on the suspension frame, it can use the attraction between itself and the ferromagnetic track to balance with the vehicle's weight, allowing the vehicle to leave the ground!"

"In addition, this type of car-rail-hugging structure can also prevent the car body from leaving the rail."

"However, ordinary magnets cannot adjust their magnetic force, so how can we deal with changes in the train's load? Just add some electricity."

At this point, the video feed switched to a woman providing commentary, demonstrating an experiment in the laboratory where she had just been performing an experiment to change magnetic force using electric current.

Upon seeing this, whether it was people like Lao Zhu and Xu Da who didn't understand the principles of electromagnetic science, or people like Zhu Xiong Ying who had some knowledge of it, they all felt that the scientists of later generations were amazing for coming up with such a method.

"Utilizing the electromagnetism effect, a magnetic field is generated around a current-carrying coil. The greater the current, the stronger the magnetic field. This is the electromagnet with controllable magnetic force!"

"In this way, as long as the coil current is automatically adjusted by the control system, it can be ensured that the train and the track always maintain a 10-millimeter suspension gap."

"Furthermore, there are two sets of coils on the side of the suspension frame—when the train deviates to one side of the track, by adjusting the current, the train can be pulled back to the center position, thereby achieving the purpose of controlling the train's steering."

"Now, our 'surface aircraft' has smoothly left the ground, and the next step is to 'move forward'."

Next, the video moves into its third segment, "Goodbye, Engine."

It also uses various experiments and animations to explain how maglev trains use rapid changes in the direction of electric current to continuously change the magnetic field and propel the train forward using the moving magnetic field.

While those with some scientific knowledge, such as Zhu Xiong Ying, could understand the preceding passage, this part proved more difficult for them. It wasn't that they couldn't understand it at all, but rather that they only vaguely grasped it.

As for Zhu Yuanzhang, Xu Da, Tang He, and others who were originally unfamiliar with this scientific knowledge, it was naturally "like listening to heavenly books, they were confused but impressed."

The fourth section of the video is titled "Goodbye, Speed ​​Limits".

"When the train speed exceeds 400 kilometers per hour, air will become the biggest resistance affecting the train's movement, accounting for more than 80% of the total resistance."

"These various car front shapes are designed to minimize aerodynamic drag, but this does not fundamentally solve the problem."

The video shows high-speed trains such as high-speed rail and maglev trains running in real life. The trains are seen speeding by, and the surrounding scenery is blurred, which even makes some older people dizzy.

The young man felt a little better, but still felt unwell for a while.

Then everyone suddenly realized—they had previously thought that the design of train locomotives in later generations was purely for aesthetic reasons, but they never expected it was actually to reduce air resistance.

Although Zhu Yuanzhang did not understand these principles, he could understand that air would act as a resistance at high speeds—when riding a horse at full speed, there would be oncoming wind blocking the way, right? The faster the speed, the stronger the wind felt.

This wind must be the air resistance mentioned in the video.

"So, an even bolder idea was proposed—to make the air disappear!"

"This is vacuum tube transportation, also known as the hyperloop. Its speed can even exceed 1000 kilometers per hour, which is faster than existing commercial airliners!"

In the video, a train is seen speeding through a transparent glass tube, its speed increasing rapidly.

Zhu Yuanzhang and others found the idea bold and ingenious, while Zhu Bai, Zhu Xiong Ying, and others who had some scientific knowledge found it even more unbelievable—as far as they knew, humans needed to live in an environment with air, and a vacuum not only lacked the oxygen that humans needed, but would also create internal and external pressure problems.

Therefore, it's easy to imagine how difficult it would be to make a train run in a vacuum tube.

Sure enough, the woman who conducted the experiment reappeared, explaining in the virtual laboratory:
"But don't get too excited yet. Conventional magnetic levitation isn't enough to reach such speeds, because what's preventing it from accelerating is itself!"

"This is an electromagnet. Under an infrared camera, you'll find that it gets hotter than a regular magnet. This is because the coil has resistance, and when energized, it generates heat and losses. Such high temperatures not only threaten the safety of the train system but also weaken the magnetic field strength."

"Are there any materials that don't generate heat? Yes!"

All the viewers saw in the video was a woman holding up a large blue bucket, scooping out some liquid with a long-handled spoon, and then a thick cloud of cold air rolled down, making it look extremely cold.

"When the temperature drops to a certain level, the resistance of this material suddenly drops to zero, which is why it's a superconductor!"

"By simply energizing the superconducting coil once, the current can be permanently locked inside, turning it into a super magnet!"

The man then explained, "Using a different principle than the Shanghai Maglev Train, Japan's low-temperature superconducting maglev train achieved a speed of 603 kilometers per hour with passengers in an environment of -269°C in 2015."

"In 2021, the world's first high-temperature superconducting high-speed maglev engineering prototype, developed by Southwest Jiaotong University in China, successfully rolled off the production line. It is designed for a speed of 620 kilometers per hour and has raised the operating temperature to -196°C."

"However, to maintain such a temperature, an additional cooling system is still needed, so it is still in the engineering verification stage."

"But this cannot stop people from continuing to explore, because maglev opens a door to a future of infinite possibilities!"

This video, which is over ten minutes long, has now reached its final segment: Hello, Future!

It describes other applications of magnetic levitation, such as helping airplanes take off from aircraft carriers, assisting in rocket launches, and being mounted on satellites, cars, and so on.

When the video ended, the viewers were still staring blankly at the screen, unable to come to their senses for a moment.

About ten seconds later, Tang He exclaimed, "It's truly unbelievable! We originally thought that the trains in the Ming Dynasty could travel from the capital to Beiping in just two or three days, which was fast enough. We never imagined that there would be even faster trains in later generations!"

Xu Da also spoke up, asking, "Marquis Jiangning, the video says that in later generations, China has already invented a maglev train that can travel at 620 kilometers per hour?" (End of Chapter)