Question

Railway civilengineer

What is the effect of selecting different types of sleepers, rail size, and subgrade strength on the granular layer thickness?

Answer 1

Sleepers act as a medium between the rails and the granular layer (ballast). Wooden sleepers are more elastic and can be used with less thickness or without a granular layer if subgrade is of good quality. cast iron sleepers require more thickness of ballast due to its rigidity.

Rail size affects the thickness of the ballast based on the bending stresses. To reduce the bending stresses in the rail the ballast thickness is kept more.

Subgrade strength is inversely proportional to the thickness of the ballast used. More is the strength of subgrade lesser is the chance of settlement and lesser thickness can be provided for the ballast.