An oil-immersed sleeper was lying on the line, black in color, looking nothing strange. Many people think it is wood soaked with oil, and the process is simple. I know it after a round in the workshop, from logs to sleepers that can go on the track, there must be several passes in the middle. The sequence is fixed, and it's impossible to move one step.

The first course is material selection. The wood used for making sleepers should be picked up. Pine wood has a large head. The figure shows that it has long fiber and tenacity and can rebound when pressed. Pine wood with turpentine, insects smell uncomfortable, this is also a natural cost. The materials shall be delivered to the site once, and the texture shall be smooth, the material shall be solid, and the unqualified materials shall not be left for the next time.

Cut the picked wood into standard size plain sleepers. At this point, it was just a piece of moulded wood, free from the word corrosion.

The next step is to dry. The cut plain sleepers are stacked into ventilation piles layer by layer. The joints between the wood and wood are reserved, and the bottom is padded to allow the wind to pass through the joints, so as to slowly take away the excess water inside. This step should not be urgent. When the wood contains too much water, the water will occupy the fiber and the oil behind cannot be squeezed in at all. Forced to dip, the oil can only hang a layer on the outer skin. It looks black and the inner part is still dry. Therefore, drying must be carried out before oil immersion, which is the most immovable part of the whole line.

Dry to a proper degree, and make a shallow opening on the wood surface, which is called nick. The wood surface is dense, and the oil has a way to go deep. These shallow ports are oil doors that allow it to follow the fiber, not just spin on the skin. It makes sense to open the mouth shallowly, just walk when it is oily enough, and the wood's own ribs are damaged when it is deep.

Following into the tank. The oil is hot, and the hot oil is better than the heavy oil in the aisle, and it is drilled along the fiber seam. The tank is pumped first to make room for the air in the fiber space, and then the oil is pumped in. One pumping and one pressure make the oil enter deep and evenly. The sequence of these two steps is also fixed. In turn, the pressure is pressed first and then the pumping is carried out. The air is blocked inside, and the oil top mostly sticks to the surface layer.

Not calculated out of the tank. The wood comes out of the pot and the oil is still moving deep, giving it time. The manufacturer will let it sit for a while and wait for the outer layer to dry before moving down. I was anxious to leave the factory, and the mind of the previous processes was reduced.

The two ends of the wood must be treated separately. When the fibers come here, they break off flush, like a bundle of straw, and water runs in faster than anywhere else. Ending two ends shall be added one more time, and the bundle and seal of the bundle shall be sealed.

The last thing is bundling and counting before going out.

The chain runs from top to bottom, each ring paving the next. Only when materials are accurately picked, water flows clean and openings are properly opened can oil enter and go deep. Before pumping, give enough time to pump out of the tank, and do enough oil work. Reverse one step forward and backward. There is little difference between the finished products. The color inside is different.

Different lines pay different attention to this process. Sleepers are pressed every day on the heavy-loaded freight trunk line. What is really hard to see is the depth of oil immersion. The special line of the mining area has heavy moisture, and the oil layer is the basis for wood to be reliable. Sleepers on the bridge are subject to various forces, and the elasticity depends on the wood itself. The durability depends on the oil penetration.

Qingdao Tiehan makes oil-immersed sleepers in this order from the beginning to the end, picking materials, drying, scoring and soaking, which is not economical. All these efforts are focused on what wood is in hand and how it leaves the factory.