RU2785306C1 - A method for determining the lengths of rails of equalizing spans and places of temporary repair of the bar by flaw detection signals - Google Patents

Abstract

FIELD: non-destructive testing.

SUBSTANCE: invention relates to methods of non-destructive testing of metals and can be used for the maintenance and operation of railway infrastructure by determining the exact coordinates and parameters of sections of rail tracks detected using flaw detection. The method comprises installation of a rail flaw detection tools on the rail moving unit, as well as the installation of global satellite navigation and relative navigation systems using the wheel of the moving unit, the moving unit is moved along the rail track, the rails are constantly tested by flaw detection tools, response signals are received from the rails, the coordinates of which are stored in the form of a flaw diagram of the rail track together with data navigation systems, the signals of the flaw detection tools are analyzed. At the time of the flaw detection, the temperature of the rails is measured, the lengths of regular objects of the rail bar are isolated and measured according to the flaw diagram, their average value is determined, a correction factor is obtained as the ratio of the lengths of the measured average value to the specified length of regular objects. Taking into account the obtained coefficient and temperature, the actual values of the lengths of the equalizing and temporary rails of the bar are calculated. The values of the joint stagger on one rail line are determined relative to the opposite joints on the other line by comparing the coordinates of the signals from the bolted joints on both lines.

EFFECT: present invention improves the accuracy and reliability of determining the lengths of the rails of the equalization spans and the places of temporary repair of the rail bar using the flaw detection signals in automatic mode.

1 cl, 4 dwg

Description

The method for determining the lengths of rails of a seamless railway (railway) track refers to methods and means of non-destructive testing of materials and can be used in the maintenance and operation of modern rail tracks and other extended metal products. The inventive method can be applied to determine the exact coordinates and parameters of problem areas of the railway. infrastructure detected by the appropriate diagnostic tools.

The jointless railway track is the most progressive and widespread design of the track structure, which gives a significant technical and economic effect due to a number of its advantages compared to the link track [1].

A jointless track usually consists of welded rail lashes 800 m or more in length, which are separated by leveling spans (two, three or four discharge rails on both tracks), turnout zones and station tracks. In recent years, the organization of jointless rail lashes up to the span (up to 35 km) has been progressive.

It is known that in the cold season the rails are shortened, and in the hot season they are lengthened. The main difference between the operation of a seamless track and a conventional link track is that significant longitudinal stresses act in the rail lashes caused by temperature changes. When laying the rail lash for a constant mode of operation, the optimal temperature for fastening the lash (neutral temperature) is usually 30-35°C, and the temperature stress in the lash is zero.

With an increase in the temperature of the lashes in comparison with the temperature of fixing, longitudinal compression forces arise in them, which can create a danger of ejection of the track and derailment of the rolling stock. At low temperatures, tensile forces appear in the welded lash, which can cause the lash to break and form a large gap that is dangerous for the passage of the train, or rupture of the rail joint due to shearing of bolts in the bolted joints.

If a dangerous rail defect is detected in the welded lash, the damaged area is cut out, and a temporary rail (cabin) 8–11 m long is laid instead of it, with the cabin installed in butt plates [2]. Thus, in the place of temporary restoration of the lash, two bolted joints appear, which violates the integrity, temperature-stressed state and stability of the seamless track.

As of 2020, the Russian Railways network has about 200,000 temporary restoration sites. Each new tie-in in a jointless lash (with two bolted joints) negatively affects the smoothness of the trains. The ends of the rail lashes adjacent to the newly formed cabin become "breathable", i.e. can change their original length with changes in ambient temperature. Uncontrolled thermal expansion of the rail lash, in turn, can lead to the so-called "ejection" of the track and to the derailment of the rolling stock.

Information about the actual values of lengths, temperatures, number and track coordinates of leveling rails and temporary cuttings is very important for knowing the actual state of the seamless track and checking its compliance with the passport project in order to identify violations of the current track maintenance. The specified information is manually entered into the paper and electronic Journal of accounting for the service and temperature regime of rail lashes (in the distance of the track) and into the centralized computer program "Unified corporate automated infrastructure management system along a seamless track" of JSC "Russian Railways" (program "EKASUI BP") [3 ].

Known technical solutions aimed at monitoring the condition and repair of places of temporary restoration of the rail whip [4-7]. Naturally, before repair, as a rule, the coordinates and lengths of temporary rails are determined manually. Known technical solutions are mainly aimed at various methods of restoring a seamless rail lash by performing welding. In [7], it is proposed to control the state of a long object (rail) by laying a fiber optic cable along the rail, which requires significant capital investments and increases the cost of the rail track design.

Manual measurement of the lengths of equalizer and temporary rails along the entire length of the track, constant monitoring and manual entry of all changes in seamless lashes into paper and electronic journals, as well as into the EKASUI BP computer system, are time-consuming tasks. In addition, when manually entering data, employees make mistakes (misses) and do not have time to make all changes in the state of the lashes in time.

Another parameter of the railway way, according to the Instruction [2], is the requirement that the bolted joints of both rail threads should be located on the square (opposite each other). The run of the joint along one rail thread relative to the joint of another thread in straight sections should be no more than 80 mm.

To check the correct position of opposite bolted joints, a special square tool is used, consisting of two unequal lengths of thin boards about 1–2 m long, fastened at a right angle [2]. Despite the fact that more modern devices have recently been proposed, for example, based on a laser emitter [8], elements of manual fixation of the value of the run of joints, and hence possible errors of a subjective nature, are not excluded.

Thus, for an objective assessment of the temperature-stress state of a seamless track, it is advisable to automate the following processes:

- fixing the coordinates of bolted rail joints;

- determination of the lengths of equalizing and temporary rails in lashes;

- determination of the value of the run of the bolted joints of the joint on one rail thread relative to the joint of the other thread;

- introduction of an array of data and changes to the Unified Corporate Database "EKASUI BP" of JSC "Russian Railways" to solve the problems of ensuring the stability of a seamless track.

The known method [9] for diagnosing a rail track allows a magnetic flaw detector installed on a flaw detector car to detect defects and structural elements of rails (bolted and welded joints, rail metal plates, turnouts, etc.). The signals from these elements and their position are stored in the diagnostic map (in the form of computer files of defectograms). Data on the structural elements of the rail track are used for navigation during ultrasonic (US) flaw detection of the same section of the rail track. The diagnostic map is corrected according to the results of multiple ultrasound or magnetic flaw detection.

The known method [9], adopted as a prototype, allows, among other things, to detect and measure the length of the rails of the leveling spans and places of temporary restoration of the lash according to the signals of flaw detection. However, the accuracy, quality and speed of detection of these rails is low and does not meet the requirements of the current track maintenance.

The tasks solved by the claimed method are the automation and increase in the accuracy of determining the lengths and coordinates of the rails of the leveling spans and rails in places of temporary restoration of the whip, i.e. rail lengths between bolted joints.

To solve this problem, in the method for determining the lengths of rails of leveling spans and places for temporary restoration of the lash according to flaw detection signals, which consists in the fact that rail flaw detection tools are installed on the rail mobile unit, as well as global satellite navigation and relative navigation systems using the wheel of the mobile unit, moving unit along the track, constantly probe the rails by means of flaw detection, receive response signals from them, which are stored in the form of a defectogram of the rail track together with the data of global and relative navigation systems, analyze the signals of flaw detection tools, additionally measure the temperature of the rails in the process of measurements, isolate and the lengths of regular objects of the rail string are measured by the defectogram, their average value is determined, the correction factor is obtained as the ratio of the lengths of the measured average value to the passport length of regular objects, taking into account the obtained th coefficient and the measured temperature, the actual (corrected) values of the lengths of the leveling and temporary rails of the lash are calculated, and by comparing the coordinates of the signals from the bolted joints on both threads, the values of the runs of the joints on one rail thread relative to the opposite joints on the other thread are determined.

The essential differences of the proposed method compared with the prototype are:

1. Temperature measurement of rails during flaw detection. As you know, when the temperature changes, there are noticeable changes in the linear dimensions of metal products, which are very clearly manifested in long products (including railway rails). In the prototype, the issues of taking into account temperature during measurements are not considered, which leads to a decrease in the accuracy of measurements of both the coordinates and the lengths of individual track objects.

2. The lengths of regular objects (rails of a standard length of 12.5 m in leveling spans, elements of turnouts, etc.) are identified and measured according to the defectogram. As a rule, the lengths of regular objects have standard values, and their passport values can be used to correct possible measurement errors. In the prototype passport values of the lengths of regular objects to improve the accuracy of measurements are not used.

3. By comparing the coordinates of the signals from the bolted joints, the values of the runs of the joints on one rail string relative to the opposite joints on the other thread are determined. In the prototype, the issues of determining the values of the runs of opposite bolted joints are not considered.

4. In the prototype, increasing the accuracy of measuring the coordinates of track objects is achieved by fixing the coordinates of bolted joints and other objects with multiple control of the track by magnetic and ultrasonic methods of flaw detection. This method is time consuming and does not provide the required efficiency in obtaining results. The inventive method provides obtaining the required accuracy of determining the lengths of the rails between the joints from the defectogram during a single passage along the controlled section of the track.

Thus, the significant differences of the proposed method make it possible to obtain a technical result: an increase in the accuracy and reliability of determining the lengths of the rails of equalizing spans and places of temporary restoration of the rail lash according to the signals of flaw detection in automatic mode, as well as measuring the values of runs of opposite bolted joints on two threads of the rail track.

The inventive method is explained by the following graphic materials:

Fig. 1 - a fragment of the defectogram of the magnetic channel of both threads of the rail track recorded by the flaw detection tool, where:

1 - defectogram;

2 - signals from bolted joints;

3 - leveling span (discharge rail zone);

4 - place of temporary restoration of the track (temporary rail or cabin);

- величина забега болтовых стыков левой нитки относительно стыков правой нитки.

- the value of the run of the bolted joints of the left thread relative to the joints of the right thread.

Fig. 2 - algorithm for implementing the proposed method.

Fig. 3 - distribution of rail lengths (distances between bolted joints) on one of the Russian railways.

Fig. 4 - table of comparisons of the results of measurements by the magnetic method of rail lengths before and after correction.

The inventive method is implemented in the following sequence.

On the mobile unit (for example, a specially equipped flaw detector car), means for flaw detection of rails, as well as global satellite navigation and relative navigation systems using the wheel of the mobile unit (odometer) (not shown in Fig.) are installed. The mobile unit is moved along the track. The results of the operation of the flaw detection tool and the corresponding coordinates of the rail track objects are stored in the form of a defectogram 1 (Fig. 1).

Known methods on the defectogram 1 determine the signals from the bolted joints 2 (Fig. 1). To obtain maximum reliability, in the general case, all available methods of non-destructive testing (ultrasonic, magnetic, visual using video recording of rails, eddy current methods) can be used. However, this complicates the procedure for recognizing bolted joints. As the practice of rail track diagnostics shows, for these purposes, the most reliable in all weather conditions and, at the same time, relatively easy to implement, is the magnetic method of rail flaw detection (when the flaw detection tool is moving: magnetodynamic - method, in foreign literature - magnetic flux displacement method - MFL) . The method consists in magnetizing the section (head) of the rail to a level close to saturation, and fixing deviations in the level of magnetic induction in the presence of anomalies (defects or breaks in the continuity of the rail in the form of bolted joints) in the rail whip .

In the area of bolted joints (mainly from butt gaps), signals of a characteristic shape of significant amplitude are formed (Fig. 1), which stand out with high reliability against the background of wave-like signals from metal sleeper linings and rail fasteners, from welded rail joints and from interfering signals of low amplitude due to microcracks, crushing, slippage and other surface defects of the rails.

Coordinate "binding" (comparison of signals with track coordinates) to the rail track of the measurement results (defectoscopy signals) can be carried out using on the flaw detection tool:

1) global navigation systems GPS, GLONASS, which provide low positioning accuracy of the flaw detection tool (several meters at a reasonable cost);

2) a speed sensor and an odometer, in which, due to slippage, slippage, wear of the wheel of the moving unit (on which the odometer is installed), the error in fixing the path coordinate can be up to 10-20%;

3) kilometer and picket poles, beaten off by employees of the flaw detection tool, as a rule, manually and giving an error of 0.5 to 3.0 m;

4) special (magnetic or radio wave) marks applied to the rail track and automatically read by a flaw detection tool. This method is distinguished by the high accuracy of determining the path coordinates (but only in the vicinity of the marks), as well as the high cost of preparatory work.

According to the authors, the most convenient way to link diagnostic signals to the track is to use the structural elements of the track: bolted and welded rail joints, turnouts, butt plates, and other elements. These objects are well detected by the magnetic method in automatic mode and visually by the operator.

Subsequent binding to the global coordinate system is carried out by sharing data from GPS, GLONASS and relative navigation (odometer) using the wheel of the mobile unit.

рельсов как в уравнительных пролетах рельсовых плетей, так и в местах временного восстановления плети (п.2 на фиг. 2):According to the coordinates of the bolted joints x _n (n=1, ..., N), determined by the above method, calculate the lengths

rails both in equalizing spans of rail lashes, and in places of temporary restoration of the lash (item 2 in Fig. 2):

In order to minimize the table of lengths of the desired rails, an exception is made from the list of rails that fall into the zones of turnouts and station tracks (item 3 in Fig. 2). Turnouts are made according to different projects, structurally they consist of several blocks with rails of different lengths, and their accounting can complicate the procedure for identifying equalization and temporary rails and measuring their lengths. Determination of zones of turnouts and station tracks is carried out in a known manner [10].

до

).According to the array of signals on the defectogram 1 formed in the process of diagnosing the path (Fig. 1), and the coordinates of the bolted joints determined according to paragraph 2 of the algorithm (Fig. 2), regular objects of the rail track are determined. Shown in FIG. 3, the distribution of distances between bolted joints on the studied polygon of the rail track (about 170 km long) shows that the most common rails are 12.5 m long and much less often - 25 m long. Rails in temporary restoration sites mainly have lengths from 6 to 12 m and their number, as expected, is much less than rails of nameplate length (12.5 m). Taking into account the possible errors in determining the lengths of the rails according to the defectogram, the estimated range of the lengths of regular objects is set (for example, for rails 12.5 m, the estimated range is from

before

).

регулярных объектов осуществляют путем анализа всех сигналов от рельсов, длины которых попадают в оценочный диапазон по выражению (п.4 фиг. 2):Determination of the average value of lengths

regular objects is carried out by analyzing all signals from the rails, the lengths of which fall into the estimated range according to the expression (item 4 of Fig. 2):

регулярных объектов, получаемых из технической документации на рельсы [2], вычисляют значение поправочного коэффициента

, компенсирующего в определенной степени погрешность измерений длин рельсов по дефектограмме (п.5 фиг. 2) и получаем скорректированное значение измеряемой величины по выражению (3):Using the passport value of lengths

regular objects obtained from the technical documentation for the rails [2], calculate the value of the correction factor

, compensating to a certain extent the error in measuring the lengths of the rails according to the defectogram (item 5 of Fig. 2) and we obtain the corrected value of the measured value by expression (3):

от паспортной и измеряемой длины

в зависимости от температуры t окружающей среды, учитывается при обработке входного массива данных (см. п. 1 фиг. 2) по формуле:Possible rail length deviations

from passport and measured length

depending on the ambient temperature t, is taken into account when processing the input data array (see item 1 of Fig. 2) according to the formula:

where 0.0000118 is the thermal expansion coefficient of rail steel, L, m is the corresponding rail length, for example, L=12.5 m [1].

стыков на одной рельсовой нитке относительно противоположных стыков на другой нитке осуществляют путем сравнения координат сигналов от болтовых стыков на обеих нитках (фиг. 1). Выполнение этой операции упрощается, так как непрерывную последовательность дефектоскопических сигналов правой и левой ниток пути регистрируют на одной дефектограмме.Compliance with the permissible value of the race according to [2]

joints on one rail thread relative to opposite joints on the other thread is carried out by comparing the coordinates of the signals from the bolted joints on both threads (Fig. 1). The performance of this operation is simplified, since a continuous sequence of flaw detection signals of the right and left lines of the track is recorded on one defectogram.

The above calculations according to expressions (1) - (4) are performed on standard computers (microprocessors) (not shown in Fig.) installed both on board the flaw detection tool and in stationary centers for analyzing (decoding) defectograms.

To test the proposed method, a 20-kilometer section of the seamless track of the North-West region was analyzed. In accordance with the proposed method, the specially developed flaw detector car software provides automatic processing of signals (defectograms) of the magnetic channel and generates a list of bolted joints with their coordinates, track thread and rail length, indicating the temperature of the string at the time of measurement. The result of comparing the lengths measured by the program 30 pcs. temporary felling with data from the rail book (manually maintained by track workers) is shown in Fig. four.

Due to the inevitable errors in the measurement of track coordinates by known methods, the initial error in determining the lengths of fellings was significant (on average, ±135 mm on the rail). The proposed algorithm (Fig. 2) for correcting the measurement of rail lengths made it possible to reduce the measurement error to an average of ±14 mm on the rail, i.e. 10 (!) times (see Fig. 4 before and after correction).

In addition, there are errors and discrepancies with the defectogram of the magnetic channel (Fig. 4), gross errors (misses) of track workers in the manual sheet. The length of five cuttings is indicated in the hand list with a clear error (from 240 to 2225 mm). 18 stacked cuttings were not recorded, and three extra (missing or eliminated) fellings were indicated (not shown in Fig. 4).

Thus, the proposed method makes it possible to automate the measurement of the lengths of temporary and equalizing rails with sufficient accuracy for the practice of technical maintenance of jointless lashes, as well as to eliminate gross blunders in manual data entry of a jointless track.

The implementation of the proposed method with the introduction of a correction factor, as can be seen from Fig. 4, allows you to significantly improve the accuracy of determining the coordinates and lengths of the rails of the leveling spans and rails in the places of temporary restoration of the lash, i.e. rail lengths between bolted joints.

It is obvious that the proposed method makes it possible to increase the accuracy of not only the desired cuttings, but also the coordinates of any structural elements of the rail track and, more importantly, the coordinates of dangerous rail defects detected during flaw detection.

The introduction of the proposed method practically expands the scope of the flaw detector car or the diagnostic complex: with the simultaneous search for internal and surface defects in the rails, the flaw detection tool also performs measuring functions that increase the safety of train traffic.

Sources

1. Instructions for the device, laying, maintenance and repair of a seamless track. Approved by order of Russian Railways OJSC dated December 14, 2012 No. 2544r.

2. Instructions on the current content of the path. Approved by order of Russian Railways OJSC dated November 14, 2016 No. 2288/r.

3. A system for monitoring deviations (inconsistencies) in the maintenance of a seamless track and taking measures in cases of detection of deviations from passport values in the base of the Unified Corporate Automated Infrastructure Management System along a seamless track. Approved by order of Russian Railways OJSC dated November 19, 2020 No. 2539/r.

4. RU 2643324.

5. RU 2300601.

6. RU 2757644.

7. RU 2676176.

8. RU 101454.

9. RU 2521095.

10. RU 2652673.

Claims (1)

A method for determining the lengths of rails of leveling spans and places for temporary restoration of a lash according to flaw detection signals, which consists in installing means for rail flaw detection, as well as global satellite navigation and relative navigation systems using a wheel of a mobile unit, moving the mobile unit along the rail track , constantly probe the rails with flaw detection tools, receive response signals from them, the coordinates of which are stored in the form of a defectogram of the rail track together with data from global and relative navigation systems, analyze the signals of flaw detection tools, characterized in that they measure the temperature of the rails at the time of measurements, isolate and measure according to the defectogram of the length of regular objects of the rail string, their average value is determined, a correction factor is obtained as the ratio of the lengths of the measured average value to the passport length of regular objects, taking into account the obtained coefficient the actual values of the lengths of the leveling and temporary rails of the lash are calculated, and by comparing the coordinates of the signals from the bolted joints on both lines, the values of the runs of the joints on one rail line relative to the opposite joints on the other line are determined.

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