The reduce the wearing of rails, the rails are placed at an inward slope of: 

Explanation:

• Maximum load of the wheel acts near the inner edge of the rail. This causes wear and tear of rails.

• To reduce wear on rails, Top of rails of a track are placed at an inward slope of 1 in 20.

Additional Information 

Wear on Rail:

• Wear is one of the prominent defects of rails.
• When the axle loads are abnormally heavy and the train moves with very fast speed then the concentrated stresses exceed the elastic limit resulting in metal flow.
• On the gap or joint the ends are battered and at the curves the occurrence of skidding, slipping and striking of wheel flanges with rails results in wear and tear of rails.
• On the basis of position of wear, wear on rail classified as:

1. ​Wear on the top or head of rail.
2. Wear at the ends of rails.
3. Wear on the sides of the head.