What makes the steps of foot over-bridges and Railways Station to wear out slowly ?

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks why the steps of foot over-bridges and railway stations wear out slowly. This implies we need to identify the factors contributing to the wear and tear of these structures.

2. **Identifying the Key Factor**: The primary factor that causes wear and tear in surfaces where people walk is friction. Friction is the force that opposes the motion of one surface against another.

3. **Role of Friction**: When a person walks on the steps of a foot over-bridge or railway station, their foot exerts a force on the surface. The frictional force between the foot and the step surface allows the person to maintain grip and prevents slipping.

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