Sleeper Density & Spacing of Sleepers

Sleeper density= Number of sleepers per unit rail length (per unit track length for welded rail)

Factors affecting spacing/density

1. Axle load and speed
2. Type and section of rails
3. Type and strength of sleepers
4. Type of ballast and ballast cushion
5. Nature of formation

Minimum Density
MKS: Minimum sleeper density= M+7 (BG)
FPS: Minimum sleeper density= N+3 (MG)

Spacing is not uniform
Spacing is less at joints. As joints are weak points and more impact of moving loads.