ACTUAL SECURITY ISSUES
Track economy of the railways of Russia due to its material consumption is the most costly branch in the system of Russian Railways. On the railways of a number of foreign countries, for example, Australia, the United States, South Africa, the operating costs in the track economy, attributed to the unit of transportation work, are much smaller than in the domestic ones. It is known that the reliability of roads on the roads of Russia, despite the relatively high quality of the rails, is much lower than a number of foreign ones for a number of operational parameters (mean time between failures, technical resources, etc.) This situation is largely due to the lack of effective controls technical condition of roads. Numerous examples of premature rail replacement are known, carried out according to the regulations. At the same time, examples of unexpected emergency situations are known due to the sudden destruction of the rails, which could not be prevented due to the lack of the necessary measuring equipment. Here it is necessary to take into account that in the current conditions of intensive track maintenance fatigue phenomena accumulate imperceptibly in the structure of rail steel, making it fragile. The process of softening began to go unnoticed. Therefore, the rail can break down suddenly, without the appearance of fatigue cracks and other signs of fatigue wear. Existing methods of nondestructive testing in this case are completely ineffective, since there are no signs of a future fracture. The need for additional measures to protect against such accidents is the reason for additional costs, which may amount to 50% of the total operating costs. It follows that it is necessary to develop new, more effective methods for monitoring the technical condition of the rail, which can detect problems in advance, and take preventive measures to eliminate them.
In the complex program of radical modernization of the railway transport in Russia, much attention is paid to improving the carrying capacity of railways, including by increasing the weight of the train. Taking into account the limited lengths of the receiving and receiving tracks at the stations, this can be achieved only by increasing the axial and running loads of trains on the railway track. However, the increase in congestion of trains is limited by the carrying capacity of wagons and the strength of the tracks. The use of additional wagons in freight trains leads to premature deterioration of rails and a concomitant decrease in safety. The experience of successful operation on the railways of a number of countries shows that for the transportation of, for example, iron ore, wagons with an axial load of up to 30 tons and more can be used provided that the roads are ready for increased loads.
The above aspects require research on the interaction of track and rolling stock in new conditions. To obtain reliable data on the effect of increased axial loads on the stress-strain state of the elements of the track structure and their failures, not only scientific research is required, but also the development of equipment for operational monitoring of the technical condition of rails . A review of Russian and foreign sources shows that such equipment does not exist! To monitor the condition of the tracks, non-destructive testing tools are used, which can detect the problem only after the appearance of visible defects (cracks, chips, shells, voids). The main problem here is that with intensive operation in the rails an unseen accumulation of fatigue occurs in the form of a change in the physical properties of steel. There are no visible defects. But steel becomes fragile, and with the passage of another heavy-loaded composition, a fragile rail can suddenly collapse, as shown in the photo.
The photo above shows that the rail, which has a normal elastic structure, bends, but does not break. The photo below shows the cause of the accident – if fatigue is accumulated in the rail structure, then it does not bend, but suddenly breaks.
The economic efficiency of the operation of rail transport directly depends on the speed of transportation and the maximum volume of cargo that can allow transportation of transport infrastructure in each railway train. These parameters are limited to safety parameters associated not only with the design features of the tracks, but also with the ability to monitor (monitor) the technical state of these paths in real time. Therefore, effective monitoring of the technical condition of the rail is a key task, which has recently received increased attention. As a rule, research results in this area are technological secrets (know-how) and are not published. Known ready solutions in the form of measuring systems and laboratory diagnostic centers. Existing laboratory methods include strength tests (using the Vickers, Rockwell or Brinell method), measuring the size of structure fragments by means of an electron microscope, testing for rupture and compression, studying the effects of operating factors (friction, temperature, environment, etc.) the characteristics are disjointed, and do not give a general objective assessment of the properties of the materials. This makes planning difficult.