Sleepers are the footstone of silence under the railway track, bearing the weight of the train and withstanding the test of wind, rain, winter and summer. Ordinary wood is not competent for this important task. It is easy to decay and deform, and its life is short. Through a series of rigorous processes, the anti-corrosion sleepers have transformed from ordinary pine into a strong and durable "guard" on the railway line. The core of this transformation is the three key steps of wind and sun, sawing and cutting, and hot oil cooking.
Wind and sun - stable foundation
The pine logs just transported from the forest farm contain a lot of water, and the internal structure is still unstable. Directly processed and used, it is easy to shrink, warp or even crack due to water loss or environmental humidity change in the future, which seriously affects the strength and dimensional accuracy of sleepers, and also brings difficulties to subsequent anti-corrosion treatment.
Therefore, the first step is "wind and sun" - a natural drying process. The timber is neatly stacked on the open and well ventilated storage yard, exposed to the air and sunlight. The wind blows continuously, taking away the moisture on the wood surface; Sunlight provides heat, which makes the moisture inside the wood migrate outward and evaporate slowly and evenly. When the moisture in pine wood is controlled at a low and stable level, it has the basic stability as a sleeper blank, greatly reducing the risk of deformation and cracking in the future.
Sawing knife cutting - shaping and preparation
The dried pine logs have different shapes and rough surfaces. They need to be processed into uniform sizes that meet the strict requirements of the railway. This is the core task of "sawing and carving".
The huge sawing machine starts to work. According to the accurate drawings and standards, the thick logs are cut into sleeper blanks with the required length, width and thickness. Pine wood has become one of the ideal materials for making sleepers because of its straight texture, relatively uniform structure and easy processing.
But that is not enough. In order to achieve the best effect of the subsequent anti-corrosion treatment, a special treatment - scoring is also required on the sleeper surface. Special machines or cutters are used to carve many well-designed traces of depth, direction and density on the sleeper surface, opening up countless "channels" for the anticorrosive oil to enter the interior of the wood. Without this process, it is difficult for the anti-corrosion oil to fully and evenly penetrate into the wood core, and the anti-corrosion effect will be greatly reduced. Scoring is the key preparation to improve the depth and uniformity of anti-corrosion treatment.
Hot oil cooking -- injecting "longevity" gene
After drying and fine processing, the sleepers have had a qualified "body shape". However, in order to truly resist the erosion of decaying fungi, moths and termites in nature and extend the service life for decades, we must also undergo the core transformation - hot oil cooking.
The treatment is carried out in a large cylindrical anti-corrosion tank with excellent sealing. The notched sleepers are carefully loaded into the cans. After the tank door is closed, vacuum pumping begins in the tank, and then special anti-corrosion oil is injected into the tank to completely submerge the sleepers. Next, pressurize and heat.
High temperature reduces the viscosity of the anticorrosive oil and makes it easy to flow like water; High pressure is like a powerful thrust, forcing these low viscosity anticorrosive oils to penetrate into the deep interior of the wood along the natural conduits and fiber gaps of the wood, especially those pre carved tracks. This high temperature and high pressure process lasts long enough to ensure that the preservative oil can penetrate deeper into the wood to achieve the effect of deep impregnation.
When the treatment is completed, the pressure is relieved and the excess anti-corrosion oil is discharged, the tank door is opened, and we can see the new sleepers: their color is darker, the surface is saturated with oil, and the weight is increased. This indicates that the preservative oil has been deeply injected into the "blood" of the wood, forming an effective protective barrier inside and outside the wood.
Transformation completed: ordinary pine to railway guard
After being stabilized by wind and sun, shaping and preparation by sawing knife, and in-depth protection by hot oil cooking, the ordinary pine has completed its transformation into a corrosion-resistant sleeper.
Stability enhancement: pre drying treatment greatly reduces the risk of deformation and cracking of sleepers due to moisture changes, and ensures the geometric stability after laying.
Reliable strength: pine wood has certain strength and toughness, and can stably bear the load of track and train after being processed into standard size.
Anti corrosion and insect prevention: the deeply impregnated anti-corrosion oil is the core secret of sleeper longevity. It has effectively prevented the breeding and spread of decaying bacteria, resisted the gnawing and destruction of moths and termites, and extended the service life of sleepers from a few years or more of ordinary wood to decades.
Economical and durable: Although the manufacturing process is complex, the extra long service life greatly reduces the maintenance frequency and replacement cost of railway lines. In the long run, anti-corrosion sleepers are a very economical and durable choice.
Behind this seemingly inconspicuous sleeper is rigorous technology and scientific treatment. Wind and sun, sawing and cutting, hot oil cooking, each step is indispensable, which together gives the pine a strong ability to resist the erosion of years and protect the safe passage of the railway. They lay silently on the ballast and under the steel rail, bearing the heavy pressure and wind and rain day after day. It is this carefully designed transformation that enables them to perform the mission of "railway cornerstone" so reliably.
