Product Expertise: Metravi VIT-20 Video Infrared Thermometer – A case Study for Hot Axle Detection


The temperature of the Axle is one of the most crucial things that are to be checked to ensure the safety of any train, be it goods or passenger trains, as the same can indicate the health of the bearing of the wheels accurately. A hot axle can lead to a multitude of issues, the most dangerous and severe being loss of life.

So, to ensure the safety of the passengers as well as smooth operations, the Indian Railways conducts regular check-ups of the axle temperature and any trains found to have hot axle is immediately dealt with, using the robust procedures of the Indian railways C&W staff.

Earlier, the temperature of the axles was measured manually, using the back of one’s hand, definitely a very risky action! However, with the progress of technology, non-contact infrared thermometers are now being used to measure the temperature safely and easily.

The biggest challenges have been that:

  1. The temperature needs to be measured quickly as the trains have very short halt times.
  2. The temperature needs to be recorded.
  3. Accuracy is a key factor.
  4. Access to the axle is limited from the platform end.
  5. TxR staff need to do multiple jobs when the train halts,along with taking temperature and recording it manually.


In the early days of Infrared Thermometer technology, very rudimentary models were available, which had a short distance to spot ratios (which is one of the most important factors when measuring the temperature of an object from a distance), low accuracy, single use batteries and no data recording facilities. The Indian Railways needed a solution that could accurately record the temperature of the axle rapidly from a safe distance, all the while ensuring that it is also able to collect and record data for future reference.

The Need:

We understood the exact operations performed by the TxR and C&W staff for hot axle detection, studied the methods and instruments used, inquired about the innovation they required and how we could make their life easier.

We also understood from the officers the pressing need to have accurate and reliable data, which would be verifiable and easily stored long term for future reference, while also ensuring that the solution is portable, lightweight and easy to operate both by the Txr staff (while measuring the temperatures) and also by the C&W staff (while generating reports and storing the data for future reference).

Innovation by Metravi:

After about a year of development and trials of prototypes, we came out with a complete solution for Hot Axle detection – The Metravi VIT-20.

The VIT-20 was cutomised for Indian Railways needs and has the following features, which make it the most ideal candidate for Hot Axle detection for the Indian Railways.

  • The VIT-20 is a Video Infrared Thermometer that is able to record temperatures as well as videographic evidence of the collection & measurement process. The videography data makes it easy to corelate the temperature of a particular axle to the coach number and the coach number to the train, while also recording the date and time stamps of when the collection of data.

• It has a long battery life and comes with a rechargeable battery, hence, single-use batteries are eliminated and recurring costs and waste are also reduced.
• It has inbuilt as well as expandable memory, ensuring that you never run out of space.
• The ease of use is such that any TxR staff who has even used an ordinary infrared gun can easily use the VIT-20.
• It does not require any special software to transfer the data to a computer for reporting or for storage.
• It has a distance to spot ratio of 50:1, which ensures accurate temperature measurements of the axle, even from a distance (the platform).
• As per the guidelines, to judge if there is a hot axle or not, comparison of the axle temperature is done with the current ambient temperature and relative humidity. The VIT 20 offers all these measurements, which no other infrared thermometer is able to do. It measures both the ambient temperature and relative humidity while measuring the axle temperature.

Thus, the Metravi VIT-20 has proven to be the ideal instrument for aiding Hot Axle detection and is successfully being used in several divisions around the country.

All Metravi product details are available on their website:

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