The safety test is really necessary, because the railway has very high requirements for safety, the railway is different from the road, there is almost no fault tolerance, a railway at most to build a double line, in one direction, there is no replacement, once there is a problem, it is necessary to adjust the entire operation chart.

Adjusting the operation chart, even in the 21st century with advanced technology, is a very troublesome thing, of course, it has something to do with the fast pace of the 21st century, but in this era of news transmission and notification by shouting, it is even more difficult, and a little carelessness is a large-scale accident.

It took 3 days to concentrate, and in a continuous and intermittent period of one or two months, a series of adjustments were made to some key data.

According to continuous testing, the safest range for 8 horses is about 80 kilometers, that is, after a horse runs continuously for 1 and a half hours, or 2 hours, it will reduce its speed due to the consumption of strength and strength, and what problems may occur.

Since it is a railway, it is not the ability to pursue that limit, but safety, and it is the best thing to maintain the speed of the train in a safe interval, and at the same time, in the range of 100 miles, there will be no exhaustion of power, and at the same time, the speed is also the highest.

Any railway, it is enough to ensure successful operation, as long as there is no large-scale time such as overturning, otherwise, the railway will not be cut off, and a railway will be cut off, and the impact on a busy railway is very huge.

Then under the limit state, to ensure sufficient safety, according to 50 kilometers for a node, that is, less than an hour of time, and then will rest for 3-4 hours, at most a horse, a day, do not run more than 2 hours, can also ensure enough speed.

After the rotation, the guaranteed enough speed for the average horse can run for a long time of one or two hours.

Of course, the difference in horse breeds will also produce huge differences, Zhao Xin was a random horse breed at that time, maybe the top in the Northern Song Dynasty, but in the world, it is not necessarily.

Mongolian horses can even run fast for 5 hours a day, or even 6 hours, and sweep the Mongolian cavalry all over the world, and the horses on their lower bodies are actually mares, which is probably unimaginable to many people.

However, it existed naturally, and the reason why the Mongol cavalry rode the mare was not due to some bad taste, but to the real needs of battle.

In the era when Mongolia swept the world, it was the era of the least developed technology, and even the ignorance of the Mongols did not have any scientific and technological achievements, and they ran long distances, which was a battle with high logistical requirements, but Mongolia only sent 20,000 troops to start the westward expedition, and hit as far as the Danube.

This is not the so-called thousands of miles away, it is a real trek of tens of thousands of kilometers, and in the middle, the base camp, simply cannot provide enough supplies.

However, it was precisely in such an extremely unfavorable situation that Mongolia swept across the steppe and Eurasia, and was called the terrible Yellow Peril, and the reason was this mare.

The marre's tenacity, especially when they have foals, and their ability to endure extremely harsh conditions, is a foundation, but the greatest advantage is that in extremely unfavorable situations, without adequate supplies, mare's milk can be used as a substitute for water and food.

That is to say, where there is grass, when there is food for horses, there will be food for people, which is a genius initiative and the secret of the Mongol cavalry being able to sweep the world.

Similar to the magic of Mongolian horses, Xixia horses and Liaoguo horses also have their own merits, and even China has Yungui horses, which are more durable horses, but all of this can not be suitable for the current situation.

Whether it is a light ride or a heavy ride, for a horse, it is a situation where the load is very light.

Compared to horse-drawn trains, these loads are really light, about 15 tons of carriages, not equal to the front part of the horse, that will crush the horse, which is a horizontal force on a smooth surface.

It is not just the weight that determines the amount of force, but the comparison between weight and friction.

The limit of the two-wheeled carriage is about 600 kilograms, which is not the limit of the carriage, but it is already the limit of the two-wheeled carriage, and the four-wheeled carriage developed in Europe can reach 2 tons, or even more.

Different types of pavement, ordinary, completely untreated dirt roads, gravel roads, blue brick roads, and even cement roads behind, the difference in road surface and the different friction will also make the limit of the carriage gradually decrease.

But on the railway, it's different, his friction has been reduced to a minimum.

Although it is the same kind of metal, but the hardness and standard are different, Zhao Xin noticed this when designing the rails, especially did some friction experiments, simple, some like middle school students' experimental tests, so that the friction between the two kinds of steel, can be reduced to the lowest extent that can be reduced.

This greatly reduces the burden on the horse, and in the same case, the horse can hold on farther.

Similar experiments are also put on the design, the rails and wheels are specially selected, after a unique design, not only the card box is very good, not easy, after some reasons, overturned, or caused other problems.

After these most basic problems are solved, the final test data directly determines the future layout.

These data were finally summarized together, and Zhao Xin finally determined a basic data of the railway by summarizing and leaving as much margin as possible.

100 miles of a station, this station, will be divided into two directions, the train will be separated by a hundred miles for a simple stop, for horse change operations, that is to say, the horse is at most about 1 hour.

There are also quite a few regulations on the selection of horses, which must be good horses above the original Northern Song Dynasty standards, or ordinary horses from Western Xia and Liao.

In this way, the train can be pulled at a faster speed, and at the same time, the speed is monitored, and in this era, there is no such accurate test tool as a rangefinder, but it can be replaced by something else.

After all, the train is a wheeled tool, under the premise of being connected, every time a wheel rolls forward, all the wheels are the same, so a simple wire swing, the number of turns of the wheel is recorded, this is not difficult to solve, a circlip and a pick wire can be solved, and then according to the length of the fixed wheel, you can get a rough distance, in addition to the timing tool, you can simply judge the speed.

This speed, compared with the accurate ranging of later generations, has a large error, but it can ensure that the error is within 2 meters per hour, which is already a terrible accuracy.

In the era when there were no telephones, computers and the Internet, train timetables could only be determined by a fixed speed, with a clock, and then guaranteed to travel at a safe distance.

Similar tests have already begun to be carried out on the Ring Island Railway, and the accumulation of experience is also the most preliminary, but these can already be deduced from the entire railway network of the Northern Song Dynasty.

For the time being, horse-drawn trains cannot be tested in multiple carriages, and it is not possible to spread the horses apart, which is too wasteful and prone to danger, so it can only be carried out alone.

According to the standard of 8 horses in a carriage, a safe distance of 5 miles, in this way, a 100-mile interval station, even if it is 12 hours a day of uninterrupted replacement, needs to be replaced 480 times at most, that is, it needs to be prepared, close to 2,000 horses.

Extreme operation is not possible, even at night, it will be reduced, or the operation of the train will be stopped, so that under the reduction, for the time being, Zhao Xin set the standard for these stations, about 200 times a day.

A station of 200 trains needs to change horses, after a horse rests, a day can carry out about 2 hours of continuous work, then 800 horses, a 2,000-mile railway, needs to spread over 20 stations, then at least a few 16,000 horses.

How many railways did the Northern Song Dynasty need, conservatively estimated, 100,000 kilometers is a must, that is, 200,000 miles, 1.6 million horses.

This is even a basic number, in the future, when the train runs smoothly and sums up more experience, the density of the train will also increase greatly, and even reach and exceed the limit, a station needs to be replaced 400, or even 800 times, then more horses are needed.

It sounds like the biggest investment is actually the horse's body, a 2,000-mile-long single line, the total investment may be about 2 million, and the double line is about 4 million, but 16,000 horses, a little more ordinary, is 1.6 million, or even more.

But the benefits are huge, money is simply a number for the Dinghai Navy, and even more can be earned if all these horses are in place.

The railway is more efficient than the carriage, some damage, is within the range of bearing, the better the railway and tires, the friction is less, the horse uses less force, under the premise of stability, to ensure the efficiency of the use of horses, with 1.6 million horses, to complete 100,000 kilometers of railway line, this is already very generous, but their cargo volume, may be dozens of times that of ordinary carriages, or even hundreds of times.

According to the so-called density now, a safe interval of 5 miles, a single line of 2,000 miles, can accommodate 400 trains, a double line is 800 trains, a train is 15 tons, a day is basically 12,000 tons of capacity, a year may exceed 4 million tons.

This is a tiny number compared to the 21st century, but in this era, it represents almost 8 million batches of wagons, and at the same time, trafficked 2,000 miles away.

This is only an approximate number, and it does not represent everything, but as long as the railway is completed, with 16,000 horses, 8 million, or even 16 million carriages, it can be said unceremoniously, this will open up a terrible era of trains.