Ensuring the safety of train traffic is the main condition of operation for the carriage of passengers and goods around the world. This is due to a constant increase in the speed of movement on railways and accelerated wear of rolling stock. With the increase in the speed of movement, the requirements to the reliability of the rolling stock are increasing. This leads to the need to maximize the use of the car fleet without compromising safety. In particular, in Russia, the wear of wagons and locomotives is more than 50%. The movement in the “wheel-rail” system is associated with intensive wear of both components, but in particular this applies to the wheels. In the course of operation, the geometry of the wheel, the quality of its material and the condition of the rolling surface deteriorate, the stresses increase, the smoothness of the course and the level of traffic safety are reduced. Wheel monitoring for the purpose of detecting defects is a basic condition for ensuring safety, especially for high-speed trains. For example, the non-roundness of the wheel can be one of the reasons for damaging the track or running gear of the rolling stock, reducing the smoothness of the course and increasing the risk of derailment.

       With a further increase in the speed of traffic, the control over the condition of wheel sets subjected to significant static and dynamic loads becomes increasingly important and requires increased attention at all stages of the life cycle. Here, the correct organization of maintenance and repair in operation, including monitoring of technical condition, is important, which requires accurate information about the wear values of the wheel pair. Practical experience shows that increased attention should be given to monitoring the condition of wheel sets on the move of the train, which makes it possible to quickly identify defective wheel pairs, and transmit the information received to the nearest technical inspection point (PTO) for detailed inspection by the technical service. Practically all systems and devices for monitoring the geometric parameters of wheel pairs of rail cars operating in Russia use a contact measurement method. When using contact devices, the influence of the subjective factor takes place.

       This problem is exacerbated by the fact that a limited amount of time is allocated for the inspection of the staff at the PTO (within 20 to 30 minutes). In this regard, there is a need to automate the process of monitoring the wheels, which will allow to perform measurements much faster. At the same time, the accuracy of measurements can be increased, the influence of the subjective factor can be excluded, and the possibility of planning maintenance will appear, since the data on the PTO will be transmitted automatically until the composition arrives there. The use of automated wheel control allows tracking the entire operation history, and in accordance with the deterioration of the wheel elements, to predict optimal operating conditions (for example, use without restrictions, use at speeds not exceeding …, use only on domestic transport, etc.). Drawing up such recommendations allows planning the loading of the machine depot, the production of spare parts, and have a reserve of rolling stock. More recently, on the railways of a number of countries, systems have been introduced to monitor the parameters of wheelsets of rolling stock in motion, operating on the principle of non-contact optical measurement. These systems can detect wheel defects long before they can cause an accident. A number of such systems are implemented on the railways of North America, Western Europe and Australia. With their help, it is possible to measure in the dynamics such wheel parameters as the diameter, height and thickness of the ridge, the width of the wear part of the rolling surface, the thickness of the rim, etc. However, optical systems have a number of significant drawbacks that limit application. Such shortcomings include quick mud staining of optical elements, and dependence on weather conditions (in fog and precipitation any optical system gives a strong error or does not work at all). In addition, it is necessary to take into account the high cost of such systems, and dependence on foreign producers.

       This prevents their wide implementation. The above mentioned shortcomings do not have an acoustic diagnostic system developed by specialists of our company. This device consists of a microphone that is attached to a rail and a computer that processes acoustic signals. To deploy this measuring system, you do not need a specially equipped post. The microphone can be fixed on any part of the path. If a radio channel is used to connect the microphone to the computer, the operator may be at some distance in a comfortable environment indoors. When the train passes, each wheel rustles in its own way, depending on the technical condition. The computer system allows you to isolate the noise of each wheel, perform a spectral analysis of its noise, and automatically determine the degree of wear of each wheel pair, and highlight the faulty ones. The examination of the composition takes about 2 minutes (that is, the time it takes for each wheel to pass over the microphone). At the same time, there is no time lost for diagnostics. The microphone of the measuring device is placed in the usual way, where the passing trains are inspected. The relatively low cost of this equipment allows it to be implemented on all major routes, which will raise safety to a qualitatively new level.