Why Are There Stones Alongside Railway Tracks?

Traveling in a train is an amazing experience in itself. You get to witness the stunning vistas of nature, sprawling fields, cities teeming with people, or endless stretches of land with no sign of any life whatsoever. One more thing that you almost always see throughout your train-journey are those small stones lying alongside the track on which your train races?

Have you ever given any thought as to why there are almost always stones alongside a railway track?

Track Ballast

To start with, the stones that you see lying close to the railway tracks are collectively called track ballast. It basically forms the trackbed on which the railway sleepers are kept. Track ballast is packed between the sleepers, in the areas below, and  on the sides of railway tracks. I can already hear the question beginning to form in your head; what’s a sleeper?

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Concrete sleepers (Source: Wikipedia)

Concrete sleepers (Source: Wikipedia)

A railway sleeper is a rectangular support that is usually kept perpendicular to the tracks. Sleepers are known by a few other names too, like a railroad tie or a crosstie. These are usually made of wood or pre-stressed concrete, although the latter is more widely used today. The function of railway sleepers is to hold the rails upright and properly spaced.

Why Specifically Those Stones?

Chipped_Stones_beside_Rail_Tracks

Source: Wikipedia

It’s not like the construction crews put just any stone they find around the tracks. That wouldn’t do the trick. For instance, if you put smooth, round pebbles in the ballast, then they might roll or slide over each other when a train passes over the tracks; therefore, they would fail at their main job – providing solidarity to the tracks. Given that fact, you need stones of a specific type that won’t move around too much, except by kids chucking stones near the tracks, of course!

In order to guarantee that the stones stay in place, they use sharp and edged stones in the ballast. Interesting, huh?

Is That All Track Ballast Does?

In fact, the track ballast serves a number of purposes. First of all, it makes sure that tracks stay in place when super-heavy trains roll by on them. It also plays an instrumental role in keeping any vegetation in check that might grow around the tracks (and make the ground beneath the tracks weaker). Another important aspect of track ballast is that it seals out any water that may be around the tracks to actually reach the tracks on a regular basis. That doesn’t mean the ballast completely insulates the tracks from water, which would be impossible, but it does facilitate water drainage around and beneath the tracks so that water doesn’t stay near the tracks and compromise the solidarity of the ground.

A novel technique to reduce vibrations

The excessive use of railway lines for transportation poses a threat to the buildings in the areas near the tracks due to the immense vibrations the tracks experience when a high speed locomotive moves over them. Also, the loud noise that is produced when a train moves rapidly also the tracks is also a nuisance to the surrounding areas.

In order to minimize these vibrations, a fairly simple clamping technique is employed using a dynamic vibration absorber. It consists of EPDM or Ethylene Propylene Diene Monomer rubber because of its high resistance to heat, water and other mechanical strains. As a result, the vibrations are reduced to a great extent and the noise is also diminished to a bare minimum.

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What we’re trying to say should be clear… Picking up stones from around the tracks on a pleasant, sunny day and chucking them out into the nearby forest is not an ideal way to release your stress!

References

  1. Track ballast – Wikipedia
  2. International Journal of Engineering and Applied Sciences
  3. University of Wisconsin – Madison
The short URL of the present article is: http://sciabc.us/WI17A
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9 comments

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1
Karuppusamy Rangasamy

This article is very good

2
Karuppusamy Rangasamy

Urban & Country side young kids shall know about this onfo

3

Good information.

4

The Ballast also serves an important function in long welded rail sections (rails without fishplated joints). That is to prevent buckling of track in hot weather. We provide extra shoulder ballast section and keep the full ballast profile clean to stop any vertical or lateral movement of the track under thermal stress which is very common in India.
I'm an engineer with Eastern Railway ( Indian Railway ) and I maintain 51 km of track over which 400 trains (passenger trains only) passes daily.

5
intrigueintelligence

Nice info and great job

6

and in India it serves one more purpose, to facilitate stone throwers during any agitation ( Rail Roko even it may be for increase in air fare, Agitation for reservations or for that matter any agitation for any purpose. LOL )

7

Why do metro rails do not have them

8

dk_Ind is partially right in his assumption. There are few reasons for this but the most primary one is ballasted tracks will require a lot of load carrying capacity for the viaduct (the elevated bridge on which tracks are laid). We do have materials available that can do the functions of ballasted track bases but these are not as cheap a solution as ballast. Since the distances are short in Metro Rails, these materials can be used instead of the usual ballast.

Another angle is of safety. Since ballast are often prone to flying out at high speeds when trains cross over them, they are not really safe in the middle of roads which is where most metro tracks pass through.

Source: I am a Civil Engineer at Nagpur Metro Rail Corporation.

9

May be the elevated track does not need them ...but the stones can be found where the Metro is grounded...like Yamuna Bank station and shastri park train terminal