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Due to which of the following co-efficient of adhesion improves ?
Sand on rails
Dew on rails
Oil on the rails
Both b and c
Sand on rails
The coefficient of adhesion is a measure of the friction available between the driving wheels of a locomotive and the rails. Applying sand to the interface increases the coefficient of adhesion, preventing wheel slippage during starting or on steep gradients.
The coefficient of adhesion is a measure of the friction available between the driving wheels of a locomotive and the rails. Applying sand to the interface increases the coefficient of adhesion, preventing wheel slippage during starting or on steep gradients.
╬╝=WFtтАЛтАЛ тАФ where ╬╝ is the coefficient of adhesion, FtтАЛ is tractive effort, and W is the weight on driving wheels.
The coefficient of adhesion depends on the state of the rail surface. Sand acts as an abrasive material that increases surface roughness and friction, effectively countering the loss of traction caused by contaminants like oil, water, or dew. By increasing the friction force, it allows the locomotive to transmit higher tractive effort to the rails without the wheels spinning.
Adhesion is primarily a function of the rail-wheel contact surface condition.
Contaminants like oil, dew, or frost reduce the coefficient of adhesion significantly.
Sanding gear is a standard feature in locomotives to handle poor track conditions.
High adhesion allows for better acceleration and steeper climb capabilities.
Prevents wheel slippage on wet or greasy rails.
Increases the maximum tractive effort possible for a given locomotive weight.
Ensures safer operation on inclines.
Can increase wear and tear on the rails over time.
Requires additional maintenance of the sanding mechanism.
Heavy haulage trains
Mountain railways
Electric locomotives in suburban transit
Dew, oil, and grease create a lubricating film between the steel wheel and steel rail, drastically reducing the friction coefficient and often leading to wheel slip.
Optimal adhesion is critical for regenerative braking effectiveness as well.
A is correct тАФ Sanding the rails increases the coefficient of adhesion by providing an abrasive interface that enhances friction between the wheel and the rail.
In competitive exams, always remember that any substance reducing friction (like oil or water) decreases adhesion, while abrasive materials like sand increase it.