When riding on the high-speed rail, do you have a question: Why is the train so smooth and quiet now? Some may think the car is getting better, or the rail technology is breaking through – but in fact, there is one of the most neglected "behind the scenes": sleepers.

More accurately, treated pine sleepers.

They are buried under the rubble all the year round, but they silently bear the train weight in ten thousand tons to keep the rail stable.

1、 What makes an unimpressive sleeper the "invisible hero" of the railway?

Sleepers have three core tasks:

-Hold the rail to prevent it from collapsing;

-Distribute the huge pressure from train to ballast and subgrade;

-Keep the gauge free from deformation and prevent the train from derailment.

It sounds difficult and it's not easy to do it.

It is exposed to the sun and rain all the year round, attacked by fungus and insect pests, and also carries the train for repeated rolling. If ordinary wood is used, it may deteriorate and distort in less than a few years - at that time, the rail is uneven, the train shakes and even derails.

So, railway engineers realized 100 years ago that wood had to be "buff-that is, treated to prevent corrosion.".

2、 Pine Wood - Why is it?

There are many options for wood for sleepers, but pine is always one of the main stream. It has tough wood, uniform structure, and excellent resistance to compression and bending. More importantly, pine trees grow fast and have a short lumber cycle, making them a cost effective sustainable material.

But it also has a fatal weakness: it is perishable and attracts insects.

Therefore, pine must undergo a "deep oil immersion" to qualify as a sleeper.

3、 An "oil-immersed treatment" that changes the fate of wood

The procedure is roughly as follows:

-First dry the wood and control the moisture in the wood to a proper degree;

-And then send it into a sealed high-pressure tank;

-Vacuumize and re-pressurize to immerse preservative oil into deeper layers of wood through prolonged oil immersion.

Only in this way can the wood be protected from the inside to the outside and will not deteriorate easily even if buried in wet gravel for decades to come.

4、 Wooden sleeper vs. cement sleeper: Who is the best match for rail?

It is true that many railways now use concrete sleepers because they are stronger and more durable. But many don't know that wooden sleepers are advantageous in some cases.

The rigidity of cement sleeper is too strong and the shock absorption performance is poor. When the train is pressed, the vibration will be directly transmitted to the ballast bed, which will easily cause the crushed stone to be pulverized and the subgrade to be deformed.

The wooden sleeper has natural elasticity, like a "cushion", which can absorb some vibration and impact. So the train runs past:

-More stable

-More quiet

-Greater passenger comfort

In addition, wooden sleeper has good insulation, which is especially important in electrified line; It is also lighter, easier to handle and maintain, particularly in mountainous and curves.

5、 Say two sentences at the end

It is always easy to notice "visible improvements" like faster trains, flatter heads, smarter systems. But the railway system is an extremely complex whole, and many "invisible details" are equally critical.

It is like a plain pine sleeper - it has undergone drying, pressurization, oil immersion, and deep anti-corrosion treatment before it can finally be padded under the rail, bearing the weight of a thousand kilograms for several years like a day.

So the next time you're on a train, if you're comfortable with the ride, remember it occasionally - that silent, tough wood. They may be unsightly, but they are important cornerstones for China's railway to move forward steadily