Coning of Wheels in Railway – Objective | Theory | Advantage & Disadvantage

Coning of Wheels in Railway

The wheel of the locomotive is in the shape of a frustum this phenomenon is called coning of wheels. As we see the wheels of our cars are flat and they can cut any turn easily as the wheel of the wheels can be turned easily but in the case of locomotives, steering wheels is not possible. There comes conning of the wheel.  This helps the wheel to rebalance itself in turn.

Coning of Wheels in Railway

The slope of the wheel is 1:20. The same slope is provided to rails and sleepers to match it with the wheels. Due to coning, the diameter changes from small to large in a curve and stays at mid diameter during a straight path. The distance between the inside edge of wheel flanges (B) is generally kept less than the gauge (G). The result is a gap of 1cm between the flange and the running face of the rails.

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Objective of coning of wheels

Due to coning, the outer wheel travels more distance than the inner wheel which helps in easy, movement in curves and avoid derailment. Coning also reduces stress in the rails as more surface area is now in contact. Coning also reduces the sideways movement of the locomotive. It also reduces the wear and tear of tracks. As the wheels are coned, It automatically keeps the locomotive in center.

Advantage of coning of wheels

1. It Reduces the wear and tear of wheels and
2. It Prevents lateral movement of
3. The coining of wheels prevents slipping of
4. It provides stability during a
5. Coning Prevent
6. Helps in reducing slip between rail and wheel.

Disadvantage of coning of wheels

1. Pressure on outer rail is more than inner rail, results in wear of outer rail earlier than inner
2. If no base plate will be used, the rail will get
3. The horizontal component tends the rail outwards causing bending of rail.

Theory of coning

When an axel faces a curve, the outer wheel will travel more distance than the inner wheel as the radius of the outer track is more than the inner track. But it is not possible as the axle is the same. That’s why coning of the wheel is done.

Due to centrifugal force trying to pull the locomotive outside, the locomotive shifts towards the outer rail and the diameter of the outer rail increases and the inner wheel also shifts outside resulting in lesser diameter.

𝑆𝑙𝑖𝑝 = ∅(𝑅1 − 𝑅2)

𝑅2 = 𝑅 + 𝐺/2

𝑅1 = 𝑅 − 𝐺/2

Where G = Gauge distance R1 = Inner rail radius

R2 = Outer rail radius R = Radius of curve Since, G = 1.676

Slip = 0.029 m per degree.

So, for slip = 0, R1 should be equal to R2, But that is not possible that’s why due to coning,

the outer rail distance becomes more than the inner rail hence the no-slip condition is generated.

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