Then came the rails.
In later generations, rail sizes were standardized.
The width was four feet and eight and a half inches.
That is, 1435 millimeters.
This was according to European standards.
The origin of this standard is quite interesting.
Early railways were designed by tram builders.
And four feet eight and a half inches was precisely the gauge used for trams.
So, where did the tram standard come from?
The first tram makers had previously built carriages, so the tram standard inherited the carriage wheel gauge.
But why did carriages use this particular gauge?
The width of the track ruts in British roads was four feet and eight and a half inches. Therefore, if a carriage used a different gauge, its wheels would quickly be damaged on old British roads.
And where did these ruts originate?
From the ancient Romans.
Because all the long-distance old roads in Europe, including Britain, were paved by the Romans for their armies, and four feet and eight and a half inches was precisely the width of a Roman chariot.
Any chariot with a different wheel width would have a significantly shorter lifespan on these roads.
One could further ask, why did the Romans set the chariot wheel gauge at four feet and eight and a half inches?
The reason is simple: it was the width of the hindquarters of two horses pulling a chariot.
The story does not end here.
The American space shuttle's fuel tanks are flanked by two rocket boosters. Because these boosters had to be transported by train after they were built, they had to pass through several tunnels.
And the width of these tunnels was only slightly wider than the train tracks, so the width of the rocket boosters was determined by the width of the railway tracks.
Therefore, the final conclusion is: path dependence led to the width of American space shuttle rocket boosters being determined by the width of two horses' hindquarters, as established two thousand years ago.
Since Fang Er was the first to manufacture rails, there was no need to adhere to that standard.
He could set whatever dimensions he desired.
"Well," he thought, "from now on, all the railway tracks in the world will follow the rules we set now."
Nothing else mattered.
It was simply that magnificent!
Fang Er considered it for a moment and directly set the width to one and a half meters.
It was much easier to remember than that damned 1435 millimeters.
The blast furnace was fired up. Ingots of steel were thrown in again.
While the materials were melting,
Fang Er, along with Zhao Gang and others, worked on creating molds.
In later generations, domestic rails came in two lengths: 12.5 meters and 25 meters.
Given the current limitations, Fang Er made them ten meters long.
Once the molten steel was ready, it was poured directly into the molds.
After cooling, minor adjustments were made.
Fang Er personally inspected every single rail.
Any with flaws were immediately discarded.
During this process, he kept Zhao Gang by his side at all times.
He explained all the requirements and the reasons behind them to Zhao Gang.
Zhao Gang listened attentively.
Although he had not formally become a disciple, the entire Fang Family Village knew that he was Fang Er's eldest disciple.
He simply lacked a formal title.
Respect for heaven, earth, sovereign, parents, and teacher.
After Fang Er requested Zhao Gang from the Ministry of Works, he allowed him to observe and learn whenever anything was being made in the blacksmith's workshop.
Zhao Gang dared not be careless; bringing shame to his teacher would be a grave offense.
A total of thirty acceptable rails were selected.
However, the number of substandard pieces rejected by Fang Er reached over forty.
Only about forty percent were acceptable.
Indeed, the mud molds were that unreliable.
It seemed the molds would need to be redesigned later.
Alternatively, a sufficiently large forging bed could be constructed for forging.
Or, rolling processes could be used to manufacture the rails.
This was merely an experiment for now.
They would make do for the time being.
Near the Dragon Head Canal, Fang Er chose a flat stretch of ground.
He summoned all the strong young men from the village.
They busily worked on laying crushed stone and setting up sleepers.
He assigned a few craftsmen to supervise with rulers on site.
Fang Er then led Zhao Gang and the others to begin constructing the locomotive.
With the steam engine already developed, the locomotive was easier.
It primarily consisted of a chassis.
The chassis served to support and mount the steam engine and its various components.
It formed the overall shape of the train and received power from the steam engine,
enabling the train to move and ensuring its smooth operation.
The chassis was composed of four parts: the transmission system, the running gear, the steering system, and the braking system.
By the time the rails were laid, the chassis had taken a rough shape.
Fang Er handed over the remaining work to Zhao Gang.
He then drove his vehicle into Chang'an City himself.
He proceeded directly to Chengtian Gate.
After having the imperial guards announce his arrival, he straightened his robes and entered.
Li Shimin was in the Liangji Hall, attending to official documents.
Upon seeing Fang Er enter, he inquired.
"You brat, instead of staying home cuddling with girls, you've come to the palace. Something up?"
Fang Er's forehead creased.
What kind of thing was that for an emperor to say to a minister?
But he couldn't retort.
He couldn't exactly say, "I'm not married yet, why don't you give me a princess?"
He figured Chai Shao would likely beat him senseless if he heard that!
So, he replied,
"Your Majesty, my village has produced a train that can travel two thousand li a day and haul over ten thousand shi of goods at a time.
Tomorrow will be its first trial run. I request Your Majesty to take some time to come and witness the spectacle."
Li Shimin was utterly astounded!
The memorial he was holding slipped from his grasp onto the ground.
He spoke with a stutter.
"You, you, what did you say?"
"Travel two thousand li a day, and haul ten thousand shi of goods?"
Fang Er nodded.
"Yes, if it's carrying people, a thousand individuals would be no problem."
Li Shimin felt that ever since he met Fang Er, his heart was constantly being tested.
Every time this fellow produced something, his heart couldn't help but race.
Forcing down his excitement, he looked at Fang Er and asked.
"The trial run is tomorrow?"
Fang Er nodded again.
"Yes, the trial run is tomorrow."
Li Er took a sip of water and, feigning composure, said, "You may return. Tomorrow morning, I will bring the officials to observe."
Fang Er bowed to him and then exited Liangji Hall.
Watching Fang Er's retreating back.
Li Shimin had everyone else in the hall removed.
Sitting on the dragon throne, he lowered his voice as much as possible and muttered incessantly.
"Two thousand li a day, ten thousand shi of cargo, a thousand people!"
"With such divine objects! I shall conquer Nanyue! I shall annihilate Tuyuhun!"
"I shall annihilate Tubo! I shall annihilate the Tujue!"
"I, I, I must surely become an emperor for all time!"
As he spoke the last words, he could no longer suppress the fervor in his heart and burst into laughter!
Hahahahahahahahahaha!
"With trains, with firearms, with cannons!"
"Mine! All mine!"
"I want all under heaven to be my domain!"
"I want all under heaven to be my subjects!"
"I want the Tang Dynasty's dragon banners to fly in every corner of the world!"
ps: Shi Zi did his best. As a clumsy typist, he spent over 30 hours coding and produced fifty thousand characters. He has now achieved the goal of impacting 500,000 characters. Both my hands are trembling slightly, and my heart is also trembling. Shi Zi was unsure if he could achieve it when he made the pledge yesterday. But he persevered. Brothers, give me some support with free gifts and follow-up requests! I will continue updating tomorrow!