During the service life of the rail, due to passage of number of wheels, the friction between wheel and rail, forces caused due to acceleration and deceleration and the effect due to weather condition like temperature, snow and rains and the standard of maintenance of track, considerable wear and tear is caused on the vertical and lateral planes of a rail head
Types of Rail Wear
A rail may wear in three different ways
- Wear at the Top of Rail
- Wear at the End of Rail
- Wear at the Sides of Head of Rail
Wear at the Top of Rail
Wear on head of rail is due to abrasion on moving rails. It is due to the grinding action of sand or dust between the rails and wheels of the train. When train starts or applies brakes, the wheel just slides on the rails causing wear on the head. Another cause of wear at the top of rail may be excessive loading. Load coming on to a track may exceed the carrying capacity of the section thus causing the wear in the head of rail.
Wear at the Ends of the Rail
It is much greater than the wear on the head of the rail. This type of the wear is resulted due to the blows which the rail receives when the wheel jumps the space between the rail ends. The ends are battered by such blows. The contact surface between the sleepers and the rail is worn as the effect of these blows increased.
The ballast under the sleepers will loosen due to increase in the intensity of vibrations; also the sleeper will depressed due the displacement of ballast, as a result the fish plates will get loose under the constant impact of increasing vibrations
Wear at the Sides of Head of Rail
On the curve the wear of the rail takes place in both inner and outer rails. In such a case the outer wheel has to move through greater distance than the inner wheel while the inner wheel has to slide over the inner rail. As a result of this sliding wear of the inner rail occur because the metal in the rail head is burnt. Also at the curve, flange of outer wheel will strike the inner surface of the outer wheel due to centrifugal force. Thus side of the head of rail wears out.