Which of the following statements are correct about ballast?
1) Screening is the process of renewing the ballast section which has degraded.
2) Boxing is relatively loose ballast which is placed on the side of the sleepers to provide lateral stability.
3) Maximum water absorption on ballast can be 15%.
1
1 and 2 only
2
Only 2
3
1, 2 and 3
4
2 and 3 only