What is Ballast?
The granular material i.e. broken stones, shingles, gravel etc., placed under and around the sleepers to transport the wheel load from the sleepers to the formation and provide proper drainage, is called ballast.
What are work ballasts in railway track beds?
The primary reasons for using ballast are as follows:
- It provides a hard and flat bed for the sleepers.
- It keeps the sleepers in proper place during the passing of moving trains.
- This provides a somewhat elastic bed for the track.
- It transmits and distributes the load from the sleepers to the formation evenly.
- This provides a handy means of maintaining the correct level of the two rails of the track, without disturbing the railroad bed.
- It protects the surface of the formation from frost, rain and direct exposure to the sun.
- This provides proper drainage to the track and keeps the sleepers in dry conditions.
- It hinders the growth of vegetation at the time of formation.
- This prevents lateral longitudinal and vertical movement of the track.
- It provides proper super elevation to the outer rail on curves.