Functions of Ballast
Ballast is the granular material placed and packed below and around the sleepers to transfer load from the sleepers to the formation. Ballast in railway tracks performs the following function:
- It provides a suitable foundation for the sleepers.
- It transfers and distributes loads from the sleepers over a larger area of the foundation.
- It holds the sleepers in the correct position and prevents their lateral and longitudinal movement due to dynamic loads.
- It helps in maintaining the correct levels and alignment of a track.
- It acts as an elastic medium and thereby increases the elasticity of the track.
- It protects the top surface of the formation.
- It improves the drainage facility of the track.