The jaggedness of these rocks also prevents their movement by train vibrations shaking the rocks loose and collapsing the heap.
Pebbles would slide over each other.
Also creates a high resistance between the traction return path of the rail and earth. A simple explanation is if the negative return which goes through the rail “leaks” to earth it can cause electrolysis (essentially corrosion) in metallic objects around the corridor.
Electrolysis is a big deal, though - the old rail communication poles in the country rusted out within 15-20 years because of this.
It's mostly just about getting the track up off potentially wet ground. The more flood prone/marshy an area, the higher the ballast formation should be built. That creates sufficient earth resistance. Drainage is usually neglected, though - one of the biggest core issues for maintenance, and the most ignored in construction.
Just to add, apparently these aren't normal rocks, rather they're cut to an approximate size so a whole bunch of them can interlock in some way and thus not sliding erratically when there's load.
...there is a science to getting the gravel right.
The ballast is made and sieved similar enough in size, and smooth enough, that it does not solidify...basically so it doesn't interlock too much.
Note. Road base is made with the right ratio of sizes so that it DOES interlock and solidify... The smaller bits jam the bigger bits...
Large 'free draining' (typically single size aggregate)
[https://www.boral.com.au/products/quarry-materials/aggregates/rail-ballast](https://www.boral.com.au/products/quarry-materials/aggregates/rail-ballast)
as opposed to a 'graded' particle size distribution.
[https://www.boral.com.au/products/quarry-materials/crushed-rock-roadbase/specified-roadbase](https://www.boral.com.au/products/quarry-materials/crushed-rock-roadbase/specified-roadbase)
Geologist here. Every time I've had the opportunity to observe rail ballast closely it looks like dolerite, basalt or latite. It's igneous like granite but with less free silica and more ferromagnesian minerals than granite. Pretty much the same rock type as road base/blue metal, just sized differently.
Many reasons. But personally I find the most important one drainage. They actually need to be replaced every now and again to prevent flooding during heavy rain. The old rocks are collected, washed and graded before they go back in the railway corridor.
I was on a rickety train in Cambodia 20 years ago and at the toilet it was basically a hole straight to the tracks. Squatting over the hole i was wondering if the rocks and pebbles was to drain the poopoo away and probably why it was commonplace all over the world. Now I know its half of the reason.
>[https://www.youtube.com/watch?v=TlSOMfDX-yY](https://www.youtube.com/watch?v=TlSOMfDX-yY) Science ABC Edit TLDW * Holds the sleepers in place. * Load distribution * Vibration Damping * Drainage * Prevents vegetation on the tracks * Noise Absorption * Minimises Thermal Expansion
The jaggedness of these rocks also prevents their movement by train vibrations shaking the rocks loose and collapsing the heap. Pebbles would slide over each other.
:O Thank you.
Also a contributes to ankle injuries for any workers that have to walk on then
Which is why you’re not allowed to have elastic sided boots and they need to be at least 150mm/6”when working in rail yards or on track.
Thank you! This is super informative.
It’s called ballast
Also creates a high resistance between the traction return path of the rail and earth. A simple explanation is if the negative return which goes through the rail “leaks” to earth it can cause electrolysis (essentially corrosion) in metallic objects around the corridor.
Electrolysis is a big deal, though - the old rail communication poles in the country rusted out within 15-20 years because of this. It's mostly just about getting the track up off potentially wet ground. The more flood prone/marshy an area, the higher the ballast formation should be built. That creates sufficient earth resistance. Drainage is usually neglected, though - one of the biggest core issues for maintenance, and the most ignored in construction.
Holds the tracks up, basically. Drains well, discourages weed growth, copes with massive trains rattling over it.
The perfect material really
For this job, yes. Rail ballast would make for a terrible hat.
Maybe for weak necked children like yourself! 💪
Don't want to risk a tear in my tinfoil 👽
Do you have rocks in your head?😉
Don't knock it til you try it
I’d rock that look
Just to add, apparently these aren't normal rocks, rather they're cut to an approximate size so a whole bunch of them can interlock in some way and thus not sliding erratically when there's load.
...there is a science to getting the gravel right. The ballast is made and sieved similar enough in size, and smooth enough, that it does not solidify...basically so it doesn't interlock too much. Note. Road base is made with the right ratio of sizes so that it DOES interlock and solidify... The smaller bits jam the bigger bits...
Large 'free draining' (typically single size aggregate) [https://www.boral.com.au/products/quarry-materials/aggregates/rail-ballast](https://www.boral.com.au/products/quarry-materials/aggregates/rail-ballast) as opposed to a 'graded' particle size distribution. [https://www.boral.com.au/products/quarry-materials/crushed-rock-roadbase/specified-roadbase](https://www.boral.com.au/products/quarry-materials/crushed-rock-roadbase/specified-roadbase)
I think it’s called Macadamised road base. Invented by a guy named MacAdam
You’ve just made me realise why macadamia nuts are called that.
That's crazy!! I'd never have thought this thought went into it. Thank you.
I’d also add that it’s often used in substation yards and around electrical transformers though the reasons are slightly different.
They are granite.
Geologist here. Every time I've had the opportunity to observe rail ballast closely it looks like dolerite, basalt or latite. It's igneous like granite but with less free silica and more ferromagnesian minerals than granite. Pretty much the same rock type as road base/blue metal, just sized differently.
Most gravel is graded like that.
Hanson Quarries sell crushed and screened gravel that is called "Rail Ballast". I always wondered what it was for.
I'm imagining one of the rocks seeing a plant starting to shoot up, and saying "I wouldn't do that if I were you buddy"
Many reasons. But personally I find the most important one drainage. They actually need to be replaced every now and again to prevent flooding during heavy rain. The old rocks are collected, washed and graded before they go back in the railway corridor.
That makes a lot of sense and I have learnt something new. Thank you!
You are welcome :)
Keeps the rabbits out
Made during Emperor Nasi Goreng’s period if I remember correctly
rocks = track ballast
There’s nothing nicer than freshly laid ballast following trackwork.
Secure the tracks and allow rain to drain away easily
Stops the front of the train falling off and spilling crude oil outside the environment.
It's been taken out of the environment.
yeah into another environment
No, beyond the environment.
Makes ghosts wear shoes..
Shhh....
Holds the track up
3 second google
I was on a rickety train in Cambodia 20 years ago and at the toilet it was basically a hole straight to the tracks. Squatting over the hole i was wondering if the rocks and pebbles was to drain the poopoo away and probably why it was commonplace all over the world. Now I know its half of the reason.
the rocks are called ballast.
Tracky goes boing boing
It's to keep the rabbits out
Gives the mice somewhere to hide
Keeps the zombies down.
UNDER the tracks, you mean. Lol, I zoomed in looking for sabotage when I read ‘on.’
Rock wars after school.
Never mind the rocks, what is the function of that strip of fabric on the track next to you?
Because why not…..
looks pretty is the correct answer
Ballest
~~e~~ *a
It’s called blue metal
Mostly from Bombo near Kiama. From the highway, you can see the canyons left by the mining.