Why do train tracks need stones to enable a trains to run along its tracks?

Question

Why do train tracks need stones to enable a trains to run along its tracks?

Answer 1

I used to be a member of a ballast spreading and tamping crew, and I sure learned a lot about the wonder of rocks. As heavy trains pass over the tracks, it's inevitable that they'll sink and move. Having the tracks sitting in ballast makes them a lot easier to raise and line, not to mention it prevents a lot of movement in the first place. If you have a low spot that needs raising, it's easy to lift it up and tamp stone underneath. And then it's even easier to line it. As long as the ties are solid, there's not much you can't do with a hopper full of good stone.

Your question is a little tricky, though, because the ballast doesn't really need to be there. Older rail lines often get neglected, and there will be plenty of stretches that sit in dirt instead of stone. If the ground is wet, the tracks will pump as train wheels pass over them, and the whole thing is just a huge mess. Over the years, the ballast sinks into the ground, and more needs to be added. If you wait too long to add stone, the tracks sink in as well. And that's a big problem to deal with!

Answer 2

1.  Drainage

2.  Drainage

3.  Drainage

4.  Stability

5.  Support

Drainage is the whole point!  Get the water away from the track.   That makes the ties last a lot longer and prevents soft spots due to frost heave or erosion.

Stability: The rough stones end up interlocking (hooking into each other) which makes it hard for the ties to move. That way you don't have ties moving sideways (a kink), ties waddling or getting crooked. etc.  This also makes them unbelievably hard to shovel.

The Western Railway Museum inherited pea-gravel ballast, which is just terrible. It just shifts all over the place, like building your railroad track on marbles!

Support, kinda, but railroad track can sit on anything solid.  You don't NEED ballast, but your maintenance costs will be a lot lower if you have it.   Crushed stone is quite good support, though, try walking on that versus pea gravel!

Answer 3

What you're talking about would be ballast. Ballast is used to kepp the ties in place & prevent them from moving. The rail is secured onto the ties, so if the ties move, it can cause the rail to go out of alignment.Ballast (or gravel) help to keep the ties in place on the tracks.

Answer 4

because mud gets the wheels dirty.

Answer 5

Two words: support and drainage.

Try taking a stick or a metal rod and stirring it in crushed rock.  You'll find it's nearly impossible to move.  That's why ballast is so effective in holding tracks in place--keeping them level and properly aligned.  Poor ballast (often at railroad crossings) can lead to "soft spots" (mud) and if the track dips too much, the weight of the cars can cause a broken rail and derailment (I've seen it happen).

Second reason (already mentioned) is drainage.  Wood ties would rot in no time flat if left on the ground.  Proper drainage also discourages weeds from growing in the right-of-way.

Answer 6

The stones, or ballast, are to provide a stable surface that won't sink or buckle unevenly, and allow water drainage away from wooden ties, otherwise they'd rot out quicker. Usually 20 years is the life of the ties, but if submerged in water, they'll rot alot quicker.

  One rail line in Virginia, from Norfolk to Petersburg, ran thru a swamp, and they used tree trunks as a basis on the swamp floor to stabilise the ground underneath enough for a train to run thru. It was quite an engineering feat in the late 1800's. So it's not just stones that can be used for support, although they were used on top of the wooden trunks and a dirt mound as well, I guess.

- The Gremlin Guy -

Answer 7

Trains are heavy and need the surface prepared properly in order to not have settling problems.The rocks are merely to stop soil erosion from damaging the surface.

Answer 8

I guess the stones are so the tracks don't sink.  It's like when pouring concrete or tarring (looking at when they're building roads) it's a must.   It'll stop everything  from washing away underneath. Without it, big trouble!

Answer 9

The stones (usually crushed granite) is called ballast. It serves to stabilize the track and slow down the formation of kinks. Kinks, or misalignment's, form from continuous hard braking over time. Kinks also develop from temperature variations. Ballast also allows water to run through and not remain around the ties. This extends the life of the tie, and helps in northern climates where the ground freezes - and distorts - if there's water present. Some light duty railroads in the southern states don't use ballast I've noticed.

Answer 10

ballast and keeps the right of way dry. it is for dainage and support.

Answer 11

2 abzorb vibration.