(ORDO NEWS) — Probably at least once you had to walk along the railroad tracks. And most likely, you have seen a lot of gray stones that are strewn with rails and sleepers. We explain why they are needed.
If you’ve ever taken rocks off railroad tracks with you or thrown them around, don’t do it again. The integrity of the railway depends on these nondescript pebbles.
Why do we need stones on the railway?
Have you ever thought about why there are almost always stones on the railway tracks? Let’s start with the fact that the stones that you see next to the railway are called ballast.
They form the rail bed on which the railway sleepers are laid. The ballast is poured into the space between the sleepers and other rail supports, going beyond the contour of the rails.
A railroad sleeper is a rectangular support that is usually held perpendicular to the rails. They are usually made of wood or prestressed concrete, although the latter is more commonly used today. The function of railway sleepers is to keep the rails on the tracks vertical and at the correct distance from each other.
Ballast serves a variety of purposes on the railroad. It provides vertical and horizontal stability to the track under the influence of train loads and changing temperatures, and accordingly ensures that the rails remain in place when hauling extra-heavy trains.
It also plays an important role in keeping vegetation under control, which can weaken the soil under railroad tracks. Another important function of the ballast is that it protects the rails from flooding. This does not mean that the ballast completely seals the paths from water, but it does facilitate drainage so that the liquid does not wash away the ground.
In general, the general condition of the railway, the level of maximum train speeds, the service life of rails, fasteners and sleepers, as well as the costs of the current maintenance of the track and the entire system of its repairs depend on the design and quality of the ballast layer.
What kind of stones are strewn on the railroad?
At first glance, it may seem that railroad employees simply collected stones from the area and covered the tracks with them. But it’s not.
On railway tracks, only concrete stones can be used as ballast. For example, if you put smooth, round pebbles in ballast, then the stones will slide and roll while the train is moving, which means they will not be able to support the rails and sleepers.
In this regard, for the ballast, it is necessary to choose materials that will meet certain requirements. They should be:
1- Hard and wear-resistant
2- Elastic (with good cushioning ability)
3- Large, but not too large – to occupy a stable position and at the same time create a flat surface under the sleepers
4- Different shapes – cubic and elongated to improve wear resistance and create good grip
For the construction of railways, fractions of 25-60 are used (i.e., the size of the stone on the railway tracks should be from 25mm to 60mm), so the crushed stone is mixed.
For these purposes, crushed stone obtained by crushing rocks, waste from asbestos production, a pebble-gravel-sand mixture resulting from the natural destruction of rocks, coarse or medium-grained sand are well suited.
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