Ballast :-

Ballast is the granular material usually broken stone or brick, shingle or kankar, gravel or sand. It provides a suitable foundation for the sleepers. It also holds the sleepers in their correct level and position. The lateral stability of a track depends on it.

Functions of ballast :-

Ballast performs the following functions –

• Transfers the load from the sleepers to the subgrade and then distributes it uniformly over a larger area of the formation.
• Holds the sleepers in position and prevents the lateral and longitudinal movement due to load transfer.
• Imparts some degree of elasticity to the track.
• Provides easy means of maintaining the correct levels of two lines of a track.
• Corrects track alignment.
• Provides good drained foundation immediately below the sleepers and help to protect the top surface of the formation.

Types of Ballast :-

1. Broken Stone
2. Gravel / Shingle / River Pebbles
3. Ashes / Cinders
4. Sand
5. Moorum