People who do the work know that responsibility comes with the mobilization of materials. From the second you sign in, the quality account of this batch of sleepers is on your head.
So I can't fool about accepting this. Especially the corrosion resistant sleepers - they were laid on the railway, exposed to the weather and rain, and had to be carried for at least ten or twenty years. You can pass the inspection by blinking. If there is a problem in the future, it cannot be solved by blinking.
Today, I talked about where to watch after the sleeper arrives at the construction site.
Look at the section, not just the surface
Upon receipt of the sleepers, many people used to beat the surface and knock the corners, and then accepted the sleepers when they thought they were "looking good". It's like buying a watermelon with only skin color and not listening, and it's likely to step on the pit.
The correct practice is to look at the section. Sleepers treated by the oil-immersed process will have obvious oil-immersed traces on the cross section - the color is darker than the original color of the wood, and the sleepers are evenly penetrated into the wood, not just floated on the surface. Good oil immersion treatment, the immersion depth can often reach more than 13mm, that is to say, the preservative is actually "drilled" into the wood, not doing a superficial trick.
If the color difference between the inside and outside is obvious, the surface is dark and there is a piece of white flower in the inside, then the anti-corrosion effect of this batch of goods should be marked with a question mark. Pine wood itself has loose fiber and strong oil absorption capacity. If it is still like "mixed rice" after treatment, the process is mostly wrong.
Measure the dimension, and the allowable error shall not exceed the standard
Sleepers, looking rough, have requirements for dimensional accuracy. During rail laying, the spacing and elevation of sleepers are based on the design parameters. If the dimension deviation is large, the rail will be uneven.
Take the tape measure one by one. Width, thickness and length shall be measured as per the contract. If the deviation is within the allowable range, it is OK. If it is obviously "shrunk" or "enriched", the photo shall be taken and rejected.
Don't think it's a big deal. A car of sleepers mixed with several pieces of wrong size, the site workers may be easy to pave directly, and I found it wrong after paving. The rework cost is much more expensive than the original careful acceptance.
Look for cracks and don't wait for it to "show" itself
Pine wood makes sleepers with a natural stinginess - easy to crack. This is much better after oil immersion, but does not mean complete disappearance.
During acceptance, carefully walk along the surface of sleepers, with focus on the end and near the knot. Slight surface hairline is not a problem, but if the crack is deep and long, even through a part of the section, the structural strength of the sleeper will be reduced. Sleepers bear a thousand tons of train weight on the railway, with hidden damage inside, which is a time bomb.
In other words, the oil immersion process is actually very advantageous in this respect - after the preservative oil penetrates into the wood fiber, it can play a certain "moisturizing" role, and slow down the speed of wood cracking. This is why railway systems prefer oil-immersed sleepers, which are not just corrosion resistant, but also have greater stability and weather resistance than ordinary sleepers.
Only the black and white words are the basis of the contract
The last, the most tangible one - take out the contract, one by one. Whether the wood species are correct, whether the anti-corrosion grade is correct, and whether the treatment process is correct, how the contract is written and how the site is inspected.
The acceptance is not a formality, but the last insurance for your project. The parameters marked on the contract are the commitments made by the supplier to you. If you do not check them, you will voluntarily give up the right of speech.
In the end, there is no technical barrier to the acceptance of sleepers, which relies on carefulness and truthfulness. Check the oil on the section, measure the size with a ruler, find cracks with the eyes and determine the parameters according to the contract, and the quality is basically stable.
Pine wood after deep oil immersion treatment, corrosion resistance, insect resistance, deformation resistance are all on a step, in the railway such a high intensity, long cycle use scene, calculated to be cost effective solution. But the prerequisite is - you have to make sure that every piece delivered to the site is a truly qualified product.
So, don't be afraid of troubles during acceptance. Look more now and exercise less for ten years later. How to calculate the average value of this account.
