Question

Explain why wooden or concrete sleepers are kept below the railway line.

Answer 1

Part 1. Railway track:

1. A railway track or railroad track is the structure of a railway or railroad.
2. It consists of the rails, fasteners, railroad ties, and ballast, plus the underlying subgrade.
3. It allows trains to run by providing a fixed surface to roll upon.

Part 2. Explanation:

1. As we know Pressure $\left(P\right)$ = Force$\left(F\right)$/Area$\left(A\right)$= $\frac{F}{A}$ Or $P\propto \frac{1}{A}$
2. It is obvious from the above equation that if the area increases, pressure decreases. That's why wooden or concrete sleepers are kept under the tracks.
3. So the weight of the moving train will be distributed over a comparatively large area of the sleepers.
4. Hence the overall pressure acting on the ground decreases and prevents the ground’s shrinking under the weight of the train.

Thus sleepers increase the area and simultaneously reduce the pressure on the line.