top of page

Railway Safety - Wheel profile Gauge | Conicity Measurement

Updated: Feb 18, 2022

Wondering why this article is here?

One of the most recent news about a train derailment, which led to many people's deaths and injured several others, became the reason behind writing this article on derailments. No matter the country, this seems to be a common problem around the globe. Often there is news from other countries about train accidents, and a more significant portion of these are due to derailment. But this article here is not to criticize what has happened, or we do not aim to blame anyone.

What if we told you we do have a solution for this?

One can not change what is entirely natural, but we can take care of a few things as humans. So, in this article, we will try to bring forth the major reasons behind these derailments and focus on that one solution that can fight most of these reasons. So, to begin with, listed below are the top reasons which lead to derailments:

  • Broken rails.

  • Defective wheels.

  • Unusual track interactions

  • Wheel-rail interactions.

  • Improper/harsh handling.

  • Collision.

Other than just broken tracks, there are numerous other reasons why derailments occur. But no matter what the reason, the accidents involving derailments have always led to huge losses. In this article, we will try to provide a solution to some of these technical errors, capable of almost eliminating them from the list. Other than the manual/human errors, the technical errors can be completely eradicated with the help of technology. To understand this is in detail, one needs to understand the very basis of the structure and arrangement in which the wheels and the track make contact when in action. The below images give us an idea about the profiles of the wheel and rail used.

conicity measurement

conicity measurement

So, to understand the wheel's profile, we need to understand the principle of 'conicity', which is brought under application while designing the wheels for the railway tracks. Conicity is a characteristic that describes the tire's tendency to roll like a cone. In simple terms, the train wheels are not like our traditional wheels used in any other vehicle but are conical.

conicity measurement

Conicity is used to investigate the dynamic interactions between railway vehicles and tracks. The flanges are made in the shape of a cone, based on the lateral force behaviour (with a coning of 1 in 20). Which in turn affects the steering performance of the vehicle. The Conical wheel arranges itself according to the train's steering onto the track. This conical shape allows free movement of the wheels on the track during turns.

The above images explain how the conical wheels move on the track during turns (left/right) for smooth and effortless running trains. But this is not the reason why derailments happen.

Why do derailments happen?

After understanding the concept of conicity well, it will not be wrong to say that these derailments happen specifically when this conicity profile is disturbed.

The wheels on which a train runs are subjected to much wear ad tear. They have to carry heavier weights and keep running on the tracks unstoppably for longer durations. So, it is evident that the structure of the wheel might get altered due to many reasons, such as:

  • excessive rubbing of the wheel with the track

  • breaking of the wheels or track

  • overtime the withering of the wheels

  • Or any foreign particle getting attached in such a way that it changes the profile of a wheel or track, resulting in improper contact between the two and many more.

No matter the reason, the point to be concerned about is how the wheel and track make contact with each other. The below image shows a wheel that has lost its initial profile due to wear and tear and how the track will struggle to make a legitimate point of contact with it while moving. Due to an improper profile, the wheel fails to stay in contact with the wheel, and in the worst case, a single wheel derails the entire compartment, further resulting in huge loss.

Undoubtedly, these issues are looked after by the concerned authorities. But what if this alteration in the wheel profile and track get ignored due to any reasons. The profile of both decides if the wheel will continue to run smoothly on to the track or not.

What if it is overlooked due to any negligence or any such reasons?

The result will always be 'chaos' filled with huge losses.


The only solution is to ensure that the wheel and track profile is always accurately maintained. For this, the wheel needs to be checked so that it is impossible for them to be faulty or have a disturbed profile. But the sad part is that this checking is still carried out manually at most places. Although there are very advanced devices available that can help get the most accurate readings for the profile and tell immediately if the wheel is fit to be used or not. They are not widely used, resulting in human lives and the loss of government property.

Such measurement instruments use extremely easy-to-use and straightforward software capable of doing these measurements in seconds with extreme accuracy. They are so precise that even a tiny error can not escape saving so many lives.

For more detail on this, please watch this video

Or, click the link below to know more about this life-saving device.

1 Comment

Gourab Amar
Gourab Amar
Feb 18, 2022

Beautiful , Great products for railway safety

bottom of page