On any train journey, you have almost surely
seen those endless piles of stones that line the railway tracks. At a casual glance,
they might look like regular pebbles, but if you ride on trains frequently,
you may have noticed that regardless of the country in which you’re travelling, the
shape and texture of those stones are almost always the same—all across the globe!
So what’s the reason behind that? Why do such otherwise unremarkable
rocks line our planet’s railway tracks? The crushed stones that line railroad tracks
are collectively called track ballast. More specifically, the track ballast constitutes
the trackbed upon which sleepers or railroad ties are laid. As you may have seen, these
stones are packed below, between and around the railroad ties. The thickness of the track
ballast usually ranges between 25-30 cm, and varies depending on certain conditions pertaining
to the geographical location of the railway track. Track ballast usually consists of crushed
rocks or stone, but in some cases, less suitable alternatives, like burnt clay,
are also used. However, it’s important to understand that you can’t just throw a bunch
of rocks on a railroad and be done with it. As mentioned, the stones in the track
ballast have a characteristic shape, size and texture. Their surface is
not smooth and their edges are jagged, and for good reason. These rocks interlock
with each other and therefore stay in place. If you replace them with circular or smooth rocks,
they would slide over each other and compromise the strength of the track ballast. As you might
imagine, this can have catastrophic results. Railway tracks are made of steel and other
metallic parts that are prone to corrosion and rusting, as they are constantly exposed to
the forces of nature, including extreme heat from the sun, rain, vegetation and general
wear and tear. The primary reason behind the existence of track ballast is to protect the
railway track. It does this in a number of ways. 1 - Holds the sleepers in place.
Many trains, including cargo and passenger trains, roll by on railway tracks every day.
Therefore, it’s not surprising that those tracks must constantly withstand
a great deal of stress and pressure. Track ballast holds the sleepers in place, so
that they don’t move longitudinally or laterally when heavy trains roll over them. Without track
ballast, those sleepers might give away under the constant pressure of passing trains.
2 - Load distribution Trains are immensely heavy and exert
massive pressure on the tracks and sleepers. Since stones in the track ballast are jagged, they
interlock with each other. This way, the immense load that’s exerted on the sleepers and track
gets distributed evenly through the track ballast. 3 - Vibration dampening
Track ballast absorbs the vibrations caused by a moving train. The cushioning effect
provided by the stones in the track ballast adds to the comfort of passengers riding in the train.
To test this, next time you ride in a train, pay close attention to how you feel when the
train passes over a stretch of railway track without track ballast.
4 - Drainage It’s important to ensure that railway tracks
don't get flooded by rains or water clogging. Track ballast comes in handy in this regard too. It prevents water clogging or the accumulation
of water on or around the sleepers. Without it, water would accumulate on the tracks
and cause rapid rusting of their metallic parts. 5 - Prevents vegetation around the tracks
Although we all enjoy swaths of land filled with green grass, plants and trees,
vegetative growth can wreak havoc on the strength of a railway track. It’s extremely
important that there is no growth of grass, weeds or plants around the tracks. The stones
in the track ballast greatly contribute to keeping out vegetation that could compromise
the structure and strength of the track. 6 - Noise absorption
A moving train is quite loud, especially to people who are OUTSIDE the train. The crushed stones
in the track ballast offer a larger surface area than a flat plane. This greatly facilitates noise
absorption. When trains move on tracks that don’t have track ballast, they are noticeably louder.
7 - Minimizes heat expansion During the summer season, railway tracks tend
to expand due to the heat. Track ballast helps keep this heat expansion to a safe minimum,
ensuring the efficacy and safety of the track. As you can see, track ballast not only protects
the railway track and its sleepers from the forces of nature and the stress of a moving train, but
also adds to the overall comfort of passengers. Looking at those stones, you may think
that once they’re deposited in the tracks, they just lay there forever, without ever
being disturbed. Well, that's not quite true. If the ballast is covered in too much
dirt or mud, it will affect its effectiveness; it can cause debris to accumulate between the
stones and negatively impact its draining ability. Just like the railway track, track ballast
requires regular maintenance and cleaning. Sometimes, the stones are replaced
with a new set of crushed stones. There are also machines called ballast cleaners
that specialize in cleaning track ballast, which reduces the amount of manual labor required.
It’s amazing how such a seemingly random set of stones constitute the backbone of an industry
that affects millions of lives around the world!
Cool. My son learned this at 5 but not from YouTube. It was from an informative and entertaining children's show in Germany...sendung mit der elephant oder maus, I think. They were quite technical and with practical examples and so, but easy for a child to grasp. Explaining concepts about wild vegetation growth and how it hinders that in places it should. Even more interesting was the episode with the track reconditioning train/machine. It showed how all the rocks are sucked up with a powerful vacuum and then fed along a belt on top of the train cars to be cleaned, sorted by size, and then packed new again under the tracks. All in real time. I've actually seen this process take place here. Slow, loud, and cool as hell. Nice find, OP
I don't need to see some video. It's called ballast and they help keep the tracks and the ties in-place as well as protecting the track and ties from rust and rot from excessive moisture.
No problem when the ballast fails just gets a bit bumpy.
https://www.youtube.com/watch?v=9X2A2f6E5DI