What are the requirements of an Ideal material for ballast?

Ballast is the material which is in granular form, usually the broken stone or brick, kankar, gravel or sand places below and around the sleepers to transfer load from sleeper to subgrade formations and at the same time allow drainage of the railway track.

1. Ballast imparts some degree of elasticity to the railway track or permanent way.
2. Ballast also provides easy means of maintaining the correct levels of the two lines of railway track.
3. Ballast maintains the level and alignment of the railway track.

Requirement of good ballast:

1. Ballast should be tough enough to manage to crumble i.e. it should not crumble.
2. The ballast should be in proper cubical shape and angular shape with sharp edges.
3. The ballast should offer resistance to weathering and abrasion.
4. Ballast should provide a good drainage system for the railways.
5. Most importantly it should be economical.
6. Ballast should satisfy the characteristics of strength, durability, economy and stability.