The train driver in the courtyard

Xiaosigang Switch Station is a small freight switch station. As Li Aiguo drove his commuter train closer to the switch station, he heard the sound of whistles coming from afar.

A switchman in his fifties stood in front of the gate, waving a small red flag and signaling the opening of the fourth track.

"Woo—".

Li Aiguo gave the signal, and the switchman raised the small red flag on his right hand to indicate that the train was entering the station.

Like other freight switching stations of this era, Xiaosigang Switch Station is usually quiet, but today several trucks were parked there.

The small train sped along the tracks for nearly ten more minutes, and Li Aiguo could see the accident site from a great distance.

A freight train carrying spare parts overturned in a nearby cornfield; the spare parts have been transferred to a rescue train.

Workers repairing the tracks and technicians investigating the cause of the accident were all busy at the scene.

"Engineer Zhang, since no problems can be found, then there are no problems. Please sign your name on the report." At this moment, Hu Fu arrived with several officers from the safety department and was watching the engineers who were squatting on the ground working.

These people are experts at the Railway Technology Research Institute who specialize in the study of railway tracks.

Hu Fu returned to the bureau last night and inquired in detail about Li Aiguo's situation.

Upon inquiring, it turned out to be quite significant.

National Model Worker, Advanced Train Driver—any one of these titles would make the bureau's leaders treat him with caution.

However, Hu Fu was not too worried.

As long as Cao Wenzhi is firmly under control, even if Li Aiguo is the director of the General Administration, he can't do anything about him.

To achieve this goal, Hu Fu spared no expense and used all sorts of connections to invite several top technical experts from the Railway Technology Research Institute.

As long as they can confirm that the orbit is fine, then there is no problem. What could Li Aiguo possibly do to cause trouble?
Hu Fu didn't want to go against such a person, but if anyone blocked his way, he wouldn't hesitate to be impolite.

"Deputy Team Leader Hu, it seems there's nothing wrong with these tracks at the moment. However, since it concerns the nature of the accident, we should still be cautious." Zhang, unaware of Hu Fu's plans, continued working as he spoke.

"hurry up."

Seeing Li Aiguo approaching, Hu Fu put on a fake smile and quickly stepped forward.

"Comrade Patriot, in order to find out the truth about the accident as soon as possible, I have invited experts from the railway technology field."

"Railway Technology Institute?" Li Aiguo turned his head and saw the experts, surprised: "Da Shuanzi?"

Engineer Zhang was concentrating on measuring the thickness of the rails when the noise startled him so much that he almost dropped his micrometer. Fortunately, he reacted quickly and avoided damaging the valuable instrument.

Hu Fu was also taken aback by the title: "Big Shuanzi, who is Big Shuanzi?"

But then the old expert, Engineer Zhang, raised his hand shyly and said, "It's me, that's my nickname."

"what?!"

When Zhang saw Li Aiguo, he was also very excited. He stood up, shook hands with Li Aiguo, and then pulled him aside to talk about the recent progress of their group's work. He acted like a friend, but more like he was reporting on his work.

The experts also put down their work and gathered around, all of them appearing very enthusiastic.

"Comrade Aiguo, you haven't been to our Railway Technology Research Institute for a while. Director Liu Guozhang was just nagging about it the other day."

"I've been busy with other work lately."

Cough cough, turns out they're all on our side.

When Hu Fu saw this, he was shocked to find that the expert he had specially invited was actually an old acquaintance of the train driver.

But it doesn’t matter.

As long as no fault can be found in the tracks, the blame can be placed on Cao Wenzhi.

"Everyone, the bureau urgently needs your test reports. Shouldn't we hurry up?" Hu Fu reminded him from the side.

"What's the rush? These rails don't have legs." Engineer Zhang is a veteran expert, and even the bureau leaders dare to disrespect him, let alone a deputy team leader. He gave Hu Fu a good scolding.

Hu Fu was so angry that his face turned red, but there was nothing he could do.

“Old Zhang, let’s get back to work. This matter concerns a train driver’s innocence.” Li Aiguo nudged Zhang’s arm.

Only then did Engineer Zhang and several experts get back to work.

Engineer Zhang had made thorough preparations this time. He first used a test hammer to tap the rails, hoping to discern whether there were any problems inside the rails by listening to the sound.

They also used a magnifying glass to observe the track surface and a small wire hook to detect whether there were any cracks.

In addition to the traditional methods, Engineer Zhang also brought over the track inspection vehicle from the Railway Technology Research Institute.

This type of vehicle uses the chordal measurement method, which can measure the geometric deformation of the rails through a mechanical transmission device.

It can be said that every method available in this era was used.

But found nothing.

There is no problem with either the broken rails or the rails in front and behind.

“I’ve said it before, it must be the train driver’s fault. Comrade Li Aiguo, I know Cao Wenzhi is your mentor, but you can’t take his side.”

Seeing this, Hu Fu became excited again, took out the appraisal report, and asked Zhang Gong to sign it.

"and many more!"

Li Aiguo suddenly stood up and pointed to the rail: "Old Zhang, the methods you've come up with have a very low failure rate. There's no way to eliminate hidden damage inside the rail."

"I know, but there's nothing we can do. We don't have X-ray vision, so we can't see what's inside the railway tracks."

“What about ultrasound?” Li Aiguo recalled a technology in his previous life that was specifically used to probe the inside of metals.

"Ultrasound is a good method. It seems that foreign countries are developing it, but the technology is far from mature. Our Railway Technology Research Institute also considered starting a project, but we've been too busy with other work these past two years."

Zhang Gong was halfway through his sentence when he suddenly realized something and asked, "Aiguo, you also have research on ultrasonic flaw detection?"

"I know a little bit." Li Aiguo glanced at the several technologies in the system, which required a full three hundred points.

However, considering that this might involve Cao Wenzhi's innocence and the safety of the train tracks, he no longer hesitated and clicked to buy directly.

If it were anyone else, Zhang would definitely hesitate, but the person in front of him was a national model worker whose name had been written in large characters by his superiors.

"Let's go back quickly and have a good talk about this ultrasonic flaw detection."

Seeing that Zhang Gong and Li Aiguo were about to leave, Hu Fu quickly ran over to stop them.

"Mr. Zhang, you haven't signed the appraisal report yet."

"What are you signing? The assessment isn't finished yet. We're just starting to make the equipment we need for the assessment. Get out of our way and don't delay our work."

Without even glancing at Hu Fu, Zhang Gong pulled Li Aiguo onto the commuter train, and the other experts followed.

The little train sped away, kicking up leaves from the roadside trees, leaving Hu Fu standing there, stunned.

Manufacturing equipment?
Isn't this just like realizing you haven't planted rice yet when it's almost time to cook?

Are you kidding me? !

"Team leader, what should we do now?" The officers from the safety department were also confused and at a loss.

Hu Fu looked at the train gradually disappearing from view, then at the railway tracks, sighed, and said, "Protect the scene first, I'll go report to the bureau."

According to regulations, these experts need to sign the report before the accident can be classified.

Hu Fu felt like he had shot himself in the foot.

Hu Fu arrived at the switch station, contacted Ma Dele by phone, and recounted what had just happened.

“Ultrasonic testing? That’s a great tool. Deputy Team Leader Hu, Comrade Aiguo and the experts have more important work to do, let them go,” Ma Dele said with a smile.

"Then what do we do?"

"You stay there, protect the accident site, and wait for the equipment to be built."

"."

After hanging up the phone, Hu Fu looked out at the desolate landscape and felt incredibly frustrated.

*****
The principle of ultrasonic flaw detection is very simple.

Just like bats detecting obstacles, this method uses the propagation characteristics of sound waves in materials to identify defects inside and on the surface of materials by analyzing reflected, refracted, or attenuated signals.

but.

Generating ultra-high frequency sound waves is one of the technical challenges.

Li Aiguo thought of the Russian-made 6C2C.

This is a high-frequency transistor that can be triggered by a circuit to generate a Colpitts circuit, which then passes through an LC circuit with high-frequency pulses.
This method is very simple, as all of you readers know, so I, the author, won't go into detail here.

However, the Russian-made 6C2C was a rare item in those days. When the application submitted by Li Aiguo was received, Section Chief Liu of the Materials Department couldn't help but frown.

"Patriotism, what is that?"

"A type of vacuum tube, which should be available at the radio factory, is urgently needed."

"Don't worry, I'll call the radio factory right now."

News of the freight train accident had already spread to the Qianmen Locomotive Depot. The depot's leaders and workers did not believe that Cao Wenzhi's negligence had caused the accident.

Section Chief Liu knew that what Li Aiguo was going to build was related to Cao Wenzhi's innocence, so he wasted no time and made seven or eight phone calls in a row after returning to his office.

Relying on the connections I had built up over the years, I finally managed to find eleven 6C2Cs in the radio factory's logistics warehouse.

After the transistor arrived, Li Aiguo had Zong Xianfeng create a trigger circuit. When the switch was pressed, there was no response, but the indicator light on the circuit kept flashing.

When Section Chief Xing heard the news, he rushed to the workshop. Seeing the test, he was puzzled: "This doesn't seem to be of any use, does it?"

"Section Chief, the probe emits high-frequency ultrasonic waves, which are very weak. After receiving them, they need to be converted into weak signals and then amplified through multiple stages before they can be displayed," Li Aiguo explained the principle simply.

"I don't understand this."

Section Chief Xing waved his hand: "But I've brought Section Chief Liu with me. Starting today, Section Chief Liu will stay in your workshop. Just ask him for anything you need. Make sure you get the flaw detection equipment out as soon as possible."

"Don't worry, Section Chief." Li Aiguo wasn't surprised. That's how it was in those days; leaders truly treated their employees like family, not just pieces of timber.

Not only Section Chief Xing, but also the section's leaders, technicians, and employees all supported the development of ultrasonic flaw detection equipment.

Around noon, Li Aiguo was about to take Zhang Gong to the canteen for lunch when he saw the fat cook standing there as soon as he stepped out of the courtyard.

"Patriotism, why are you going to eat there yourself?"

"What are you saying? Do you expect me to eat for you if I don't go myself?"

"Ahem, that's not what I meant. I've brought you your food." The chubby cook called out to someone in the distance.

Two helpers came running over, one carrying a rice cooker and the other carrying a food box.

The rice cooker contained white rice, and the food container contained four dishes: braised pork, stir-fried pork with chili peppers, stir-fried pork with potatoes, and stir-fried pork with green beans—all hearty dishes.

"This isn't appropriate," Li Aiguo thought, feeling that the food was excessive.

"Don't worry, these are materials that all the staff in our canteen exchanged for with their own meal tickets. We can't let you make a mistake." The chubby cook nodded emphatically.

Li Aiguo glanced at the chubby chef, didn't say much, just thanked him, and then carried the rice cooker and lunchbox back to his studio.

In the following days.

Li Aiguo basically works all the time except when he's sleeping.

The 116 Engineering Workshop learned about Cao Wenzhi's situation but did not bother Li Aiguo. Cao Wenzhi's injuries had healed, and he was still in the hospital. Chen Xueru had visited him with the children.

As each component was manufactured, and the computer research institute delivered the crucial cathode ray tube (CRT) oscilloscope, all the components were completed.

The computer research institute has now partnered with a television manufacturer to develop and prepare for the production of CRT computer monitors.

Once completed, it will completely revolutionize computers, but that's another story.

On Monday morning, Zong Xianfeng and the wild car expert assembled the circuit board, Li Aiguo connected the wires, and finally put it into a heavy wooden box.

With all the wires connected, Li Aiguo turned on the oscilloscope.

"Oscilloscope is normal!" Li Aiguo shouted as he turned around. Zong Xianfeng immediately turned on the switch of the ultrasonic transmitter module, and the indicator light at the tail of the probe lit up with a faint red light.

With a barely perceptible buzzing sound, the line representing the echo wave on the CRT oscilloscope began to jump.

"Bring the test block!" Engineer Zhang stood to the side, holding a steel test block.

Li Aiguo squeezed a little industrial glycerin onto the surface of the test block. Zong Xianfeng took the probe, pressed the spring clip on the side of the probe with his thumb, and pressed the working surface of the probe tightly against the center of the test block.

All eyes were fixed on the CRT oscilloscope.

The bright lines on the screen suddenly started jumping, filled with chaotic high-frequency noise.

"What's going on?" Engineer Zhang was startled. They had put in all their effort to make this thing, and they couldn't afford to give up.

“This thing needs to be calibrated.” Li Aiguo stroked his chin, realizing he had overlooked something.

Before industrial flaw detection in later generations, it was necessary to use standard blocks to calibrate the flaw detector to avoid errors caused by differences in sound velocity.

A good meal is not afraid of being late.

Li Aiguo asked Director Zhang of the maintenance workshop to manufacture a commonly used No. 20 steel as a standard block.

标准块里面有人工造成缺陷，Φ2-5mm平底孔、0.1-0.3mm宽线切割裂纹、2-5mm厚夹杂，全都是事先布置好的，连位置都标注出来了。

"This method is absolutely brilliant." Engineer Zhang was dumbfounded. He knew that calibration was needed, but he hadn't thought of using the standard block method.

Li Aiguo smiled but didn't say anything.

Any technological advancement is not just about scientific progress, but more importantly, about the accumulation of experience by workers through practical operation.

Everyone understands the principle, but whether they can actually do it or even conceive of it is another matter entirely.

After restarting, the ultrasonic flaw detector was checked using the known defects, and the probe was once again aimed at the original piece of steel.

At this time, the waveform on the monitor is very stable and there are no problems.

“Let’s use another test block with a crack!” Li Aiguo said, taking out another test block from the iron box, which had a cutting crack on it.

Zong Xianfeng moved the probe to the crack area, and this time a series of small pulse waves appeared on the fluorescent screen.

"It's multiple reflections from the crack! The location is the same as the one marked in advance."

"I heard that hospitals abroad can perform ultrasounds, and they can see inside the abdomen through the skin. Now we can perform ultrasounds on railway tracks."

At this moment, Zhang Gong's heart, which had been hanging in mid-air, finally settled down.

A round of applause rang out in the studio.

With this thing, we can definitely figure out if there's a problem with the tracks near Xiaosigang switch station.

****
Early morning is the most beautiful time of day.

But if you're sleeping in the fields, and after a night of mosquito bites, you find a long worm under your bed, then the morning isn't so pleasant.

Hu Fu was so frightened he almost peed himself. He jumped off the bed without even bothering to put on his pants.

The flower worm glanced at him disdainfully, then calmly turned and burrowed into the field.

Hu Fu clutched his pounding heart, recalling what had happened in the past few days, and felt like crying.

After that bastard Li Aiguo left, he was ordered by the bureau to stay at the accident site to guard and protect it.

This place is a desolate wilderness, with nowhere to sleep but in the open. Food is even worse, delivered by the switch station.

The food was practically inedible.

"The hard times are finally over. As long as today's inspection is over, I can go back to the bureau and wait for my promotion."

Hu Fu became excited when he saw a small train approaching in the distance.

When he saw Li Aiguo come down carrying a strange box, he immediately frowned. Had he really come up with that kind of device?
No, that's impossible. That's steel. What could possibly penetrate steel?
"This investigation has taken too long. After today's inspection, can we sign the accident report?"

Hu Fu found Engineer Zhang and said eagerly.

Zhang Gong didn't even glance at him, and just helped Li Aiguo arrange the wires.

Since batteries haven't been installed yet, power has to be drawn from the small train, which is inconvenient to operate. Li Aiguo thinks that a portable ultrasonic flaw detector should be developed, one that can be operated by two people.

After the ultrasonic flaw detector was installed, Ma Dele and a deputy leader from the bureau also arrived.

"Boss, this is the equipment they came up with. I have a bad feeling about it." Hu Fu quickly went over to report.

"No need to say anything!" Ma Dele glanced at him sideways and walked to the railway tracks.

At this moment, Li Aiguo had already turned on the ultrasonic flaw detector. Zong Xianfeng took the detector and checked along the railway track, but the waveform on the monitor did not change.

"keep going."

As Zong Xianfeng walked, the atmosphere on the scene gradually became tense.

Seconds passed, but the waveform on the monitor remained completely still.

Hu Fu was overjoyed: "I told you long ago that there was nothing wrong with this section of track, but you didn't believe me. Now it's all right."

The voice just fell.

"Stop!" Li Aiguo raised his fist, and Zong Xianfeng immediately stopped in his tracks.

Everyone looked at the monitor, and the previously stable waveform began to jump rapidly.

"What if it works out?"

"It's hard to say. It's just a few ripples. What can that prove?"

Ma Dele looked at Li Aiguo and asked, "Comrade Aiguo, what's going on?"

"This means there's a gap inside the rail, about three centimeters long and two millimeters wide." As he spoke, Li Aiguo picked up a piece of chalk and marked the location of the probe.

"That's ridiculous. The tracks look perfectly fine. You insist there are hidden defects. Do you have X-ray vision?"

Hu Fu panicked.

If there is indeed a problem with this section of track, it is possible that the track broke due to the impact of a wheel, leading to the derailment.

All his efforts were in vain.

Li Aiguo ignored him and asked Old Chen, the track inspector, to dismantle the section of rail. He then found two large stones and placed the rail across them.

Li Aiguo took a deep breath and used a long-lost fist technique to smash the railroad tracks.

Everyone was stunned by Li Aiguo's actions, and Hu Fu even sneered.

"The rails are forged from carbon steel. If you can bend them with one punch, then I'll... *burp*."

The punch had already landed.
Punch arrived.

The rail snapped instantly.

That was a devastating punch.

Li Aiguo was slurping in pain; as expected, showing off comes at a price.

In other words, the gaps inside had reached their limit, but it didn't break only because it was firmly nailed to the track.

Otherwise, even if Li Aiguo were incredibly strong, he wouldn't be able to break it.

"Brother Aiguo, I didn't expect you to be a master of martial arts." Zhou Ke, who was also joining in the fun, clicked his tongue twice when he saw this.

"I wouldn't call myself a master." Li Aiguo wasn't being modest.

People like Chief Xu and Zuo Dongfang are true masters.

There's a saying in boxing: "Practicing boxing without internal strength training is a waste of time in old age."

According to Li Aiguo, another line should be added: "Practicing martial arts without practicing fighting is a waste of time until death."

The enemy is not a railway track, nor will it stand there and let you attack it.

If someone hits a punching bag for a few days and bends a few wrenches, and then considers himself a kung fu master, while his spirit is admirable, he's bound to suffer a great loss.

Facts speak louder than words; the broken rails speak for themselves.

Hu Fu, who had been shouting just moments before, now had a face so black it looked like ink could drip from it.

"The fact that this section of the rail has a problem does not mean that the section of the rail that had the accident also had a problem."

"Alright, let's go check that section of track."

The broken rail remained in its original position. Li Aiguo installed the ultrasonic flaw detector, aimed the probe at the rail, and the lines on the monitor began to jump rapidly.

"One inner seam, three centimeters long and one millimeter wide; two inner seams, two centimeters apart and two millimeters wide."

Upon hearing Li Aiguo's words, everyone present gasped in shock.

The rails that initially appeared to be fine were actually riddled with holes inside.

"It turns out it really was a problem with the tracks; the comrades in the safety department clearly wronged Master Cao."

"It's only because Master Cao took on a good apprentice, otherwise he would have suffered a great loss this time."

Hu Fu was now ice-cold all over. His eyes darted around rapidly, and he quickly said:

"Ahem, everyone misunderstood. We didn't mean to target Master Cao; we were just doing our duty."

"Ha, isn't it targeted to arrest Master Cao and interrogate him at the General Administration?" Several employees of the Qianmen Locomotive Depot were immediately dissatisfied upon hearing Hu Fu's words.

"I," Hu Fu, still tried to argue.

Ma Dele coughed lightly twice to interrupt him, then looked at the onlookers and said, "Please rest assured, everyone, our General Administration's Safety Department will definitely investigate this matter thoroughly and give Master Cao justice."

Ma Dele glared at Hu Fu: "Deputy Team Leader Hu, starting today, you are suspended from your duties. Go to a training course first, and come back to work after you realize your mistakes."

Hu Fu gritted his teeth, glared angrily at Li Aiguo, then turned and staggered away.

That damn train driver, this isn't over yet!

It was already close to evening.

After dealing with the accident scene, Li Aiguo and his group took a small train back to the Qianmen Locomotive Depot.

At this time, the studio also learned of the success of the ultrasonic flaw detector.

The employees were very excited.

Inside Workshop 116, Chief Engineer Qi sat at his desk, muttering to himself, "Flaw detectors can check for gaps in railway tracks, so can they also be used to inspect aircraft?"

(End of this chapter)