What is Ballast | Railway Ballast | Functions of Ballast.


What is Ballast?

Railway Ballast is the foundation of railway track and provide just below the sleepers. The loads from the wheels of trains ultimately come on the ballast through rails and sleepers.


Functions of Ballast:-

Some of the important functions of railway ballast are:
1.    To provide firm and level bed for the sleepers to rest on.
2.    To allow for maintaining correct track level without disturbing the rail road bed.
3.    To drain off the water quickly and to keep the sleepers in dry conditions.
4.    To discourage the growth of vegetation.
5.    To protect the surface of formation and to form an elastic bed.
6.    To hold the sleepers in position during the passage of trains.
7.    To transmit and distribute the loads from the sleepers to the formation.
8.    To provide lateral stability to the track as a whole.

Requirements for Ideal Ballast:-

The ideal material for ballast should fulfill the following requirements
1.    It should be possible to maintain the required depth of the material in order to distribute the load of passing train on the formation ground.
2.    The material to be used for ballast should not be too rigid but it should be elastic in nature.
3.    The material for ballast should be of such nature that it grips the sleepers in position and prevent their horizontal movement during passage of train.
4.    It should not allow the rain water to accumulate but should be able to drain off the water immediately without percolating.
5.    It should be strong enough a resistance to abrasion.

Materials for Ballast:-

The following materials are used for ballast on the railway track.
1.    Broken Stone
2.    Gravel
3.    Cinders / Ashes
4.    Sand
5.    Kankar
6.    Moorum
7.    Brick Ballast
8.    Selected Earth. 

Comments

Post a Comment

Popular posts from this blog

Lane’s Weighted Creep Theory

Image
Bligh, in his theory, had calculated the length of the creep, by simply adding the horizontal creep length and the vertical creep length, thereby making no distinction between the two creeps. However, Lane, on the basis of his analysis carried out on about 200 dams all over the world, stipulated that the horizontal creep is less effective in reducing uplift (or in causing loss of head) than the vertical creep. He, therefore, suggested a weightage factor of 1/3 for the horizontal creep, as against 1.0 for the vertical creep. Thus in Fig–1,  the total Lane’s creep length (L l ) is given by L l = (d 1 + d 1 ) + (1/3) L 1 + (d 2 + d 2 ) + (1/3) L 2 + (d 3 + d 3 ) = (1/3) (L 1 + L 2 ) + 2(d 1 + d 2 + d 3 ) = (1/3) b + 2(d 1 + d 2 + d 3 ) To ensure safety against piping, according to this theory, the creep length Ll must no be less than C1H L , where H L is the head causing flow, and C 1 is Lane’s creep coefficient given in table –2 Table – ...
Read more

What is Soil in Geotechnical Engineering.

Image
Definition of Soil The word ‘soil’ is derived from the Latin word solium which, according to Webster’s dictionary, means the upper layer of the earth that may be dug or plowed; specifically, the loose surface material of earth in which the plants grow. The above definition of soil is used in the field of agronomy (The application of soil and plant sciences to land management and crop production) where the main concern is in the use of soil for raising crops. In geology, earth’s crust is assumed to consist of unconsolidated sediments, called mantle or regolith, overlying rocks. The top soil contains a large quantity of organic matter and is not suitable as a construction material or as a foundation for structure. The top soil is removed from the earth’s surface before the construction of structure. The term ‘ soil ’ in the soil engineering is defined as an unconsolidated material , composed of solid particles , produced by the disintegration of rocks . The void space...
Read more

What is Mill bent in Industrial Buildings?

Image
The assembly of roof truss attached to and supported on column at both the ends is known as bent, mill bent or transverse bent . An industrial buildings consists of a series of such transverse bent supporting the roof. The distance between the two adjacent transverse bents is known as bay . The space between the column lines is usually called an aisle.
Read more