Rail condition calculation method and rail condition calculation system

Abstract

To provide a rail soundness calculation method and a rail soundness calculation system capable of calculating rail soundness by a simple and efficient method.SOLUTION: A rail soundness calculation method comprises: a measurement step of measuring a high / low displacement waveform and an axle box acceleration waveform of a track; a waveform calculation step of calculating a floating sleeper waveform from the high / low displacement waveform; a section specification step of specifying a peak position exceeding a predetermined threshold in the high / low displacement waveform or the floating sleeper waveform, and specifying a section having a predetermined offset amount centered on the peak position; an amount calculation step of calculating a floating amount of a sleeper which is the maximum value of the floating sleeper waveform in the section and a rail irregularity amount calculated from the maximum value and a minimum value of the axle box acceleration waveform; and a rail soundness calculation step of calculating rail stress from the floating amount of the sleeper and the rail irregularity amount to calculate rail soundness.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method and system for calculating rail soundness for evaluating the soundness of rails, and more particularly to a method and system for calculating rail soundness caused by irregularities on the rail top surface and loose sleepers. [Background technology]

[0002] Traditionally, in order to maintain and manage railway tracks on which railway vehicles run, rail corrosion, which is a cause of rail damage, has been identified to estimate the location of rail damage and prevent it from occurring in the first place.

[0003] Various methods are known for preventing such rail damage, and for example, the rail soundness evaluation method described in Patent Document 1 is known.

[0004] The rail soundness evaluation method described in Patent Document 1 is a rail soundness evaluation method for evaluating the soundness of a rail due to corrosion, and comprises the steps of: obtaining rail corrosion amount data associated with the rail position; estimating rail stress associated with the rail position; identifying rail fatigue strength based on the corrosion amount data; and calculating the rail soundness at the rail position based on the rail stress and rail fatigue strength.

[0005] This method for evaluating rail integrity allows for the acquisition of rail corrosion data associated with a specific rail location to determine rail fatigue strength, as well as the estimation of rail stress associated with that location. Based on the obtained rail stress and rail fatigue strength, the rail integrity at each rail location can be calculated. Therefore, by utilizing not only rail corrosion data but also indicators and estimation results that show track condition, it is possible to efficiently quantitatively evaluate the rail integrity at any rail location on an operational line. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-075806 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, according to conventional methods for evaluating rail integrity, applying this evaluation method to the maintenance and management of operational railway tracks presented the following challenges in terms of data processing for the step of estimating rail stress, as described above. First, in order to achieve safer rail management, it is considered more appropriate to refer to data within a certain range, taking into account the actual occurrence characteristics of floating sleepers and irregularities on the rail top surface, whose location and occurrence amount change continuously, rather than limiting the data to a single point on a specific kilometer on the chart. However, a data processing method to achieve this had not been established. Furthermore, since water leakage that promotes rail corrosion and irregularities on the rail top surface is known to occur inside tunnels, etc., there was also the challenge of needing to process and extract data according to its positional relationship with ledger data for tunnels, etc., rather than considering the entire range of track kilometers.

[0008] Furthermore, the rail integrity evaluation method described in Patent Document 1 uses data on vertical displacement and axle box acceleration. However, the sampling intervals for these data differ, being 25 cm for vertical displacement and 1 cm for axle box acceleration, making it difficult to simply compare the data. In other words, different sampling intervals necessitate a method for identifying the values ​​of vertical displacement and axle box acceleration for arbitrary kilometers. Additionally, if there is a shift in the peak position of the vertical displacement and axle box acceleration data, the rail integrity will be overestimated, making it impossible to evaluate appropriately.

[0009] Therefore, the present invention has been made in view of the above problems, and aims to provide a method and system for calculating rail soundness that can calculate rail soundness in a safer and more efficient way. [Means for solving the problem]

[0010] The rail soundness calculation method according to the present invention comprises: a measurement step of measuring the track's height displacement waveform and axle box acceleration waveform; a waveform calculation step of calculating a floating sleeper waveform from the height displacement waveform; a section identification step of identifying a peak position in the height displacement waveform or floating sleeper waveform that exceeds a predetermined threshold, and identifying a section having a predetermined offset amount centered on the peak position; a quantity calculation step of calculating the amount of rail irregularity calculated from the maximum value of the floating sleeper waveform in the section, which is the amount of sleeper floating, and the maximum and minimum values ​​of the axle box acceleration waveform; and a rail soundness calculation step of calculating rail stress from the amount of sleeper floating and the amount of rail irregularity to calculate the rail soundness. The rail soundness calculation process involves referencing ledger waveform data, which is obtained by converting ledger data of at least one of the tunnel or track bed types into waveform data, to extract the rail soundness only within the tunnel, the rail soundness only on the ballast track, or the rail soundness only on the ballast track within the tunnel. It is characterized by doing so.

[0011] Furthermore, in the rail soundness calculation method according to the present invention, it is preferable that the quantity calculation step involves multiplying the floating sleeper waveform or axle box acceleration waveform by 0 to create a waveform of 0 for the entire section, and then performing a process to replace the data within the section of the waveform of 0 for the entire section with the maximum value of the floating sleeper waveform and the maximum and minimum values ​​of the axle box acceleration waveform.

[0012] Furthermore, in the rail soundness calculation method according to the present invention, it is preferable that the rail soundness calculation step calculates the influence of the amount of sleeper lift and the amount of rail irregularities, respectively.

[0014] Further, the rail soundness calculation system according to the present invention comprises: measuring means for measuring a track height displacement waveform and an axle box acceleration waveform; waveform calculation means for calculating a floating sleeper waveform from said height displacement waveform; section specifying means for specifying a peak position exceeding a predetermined threshold value among said height displacement waveform or said floating sleeper waveform, and specifying a section having a predetermined offset amount centered on said peak position; quantity calculation means for calculating a sleeper floating amount calculated from the maximum value of said floating sleeper waveform in said section, and a rail irregularity amount calculated from the maximum value and the minimum value of said axle box acceleration waveform; and rail soundness calculation means for calculating a rail stress from said sleeper floating amount and said rail irregularity amount to calculate a rail soundness The rail soundness calculation means refers to ledger waveform data, which is obtained by converting ledger data of at least one of the tunnel or track bed types into waveform data, and extracts the rail soundness only within the tunnel, the rail soundness only on the ballast track, or the rail soundness only on the ballast track inside the tunnel. , which is characterized by the above.

[0015] The above summary of the invention does not list all necessary features of the present invention, and subcombinations of these feature groups may also constitute the invention. [Effect of the Invention]

[0016] The rail soundness calculation method and rail soundness calculation system according to the present invention comprise a section specifying step of specifying a peak position exceeding a predetermined threshold value among the height displacement waveform or the floating sleeper waveform, and specifying a section having a predetermined offset amount centered on said peak position. Therefore, even when using data with different sampling intervals, it is possible to automatically calculate rail soundness using track inspection data, axle box acceleration data and ledger data, and automatically extract locations requiring attention for rail fracture considering structures such as tunnels. [Brief Description of the Drawings]

[0017] [Figure 1] Flow diagram of the rail soundness calculation method according to an embodiment of the present invention. [Figure 2] Diagram showing waveforms used in the rail soundness calculation method according to an embodiment of the present invention. [Figure 3] Detailed flow diagram of the rail soundness calculation method according to an embodiment of the present invention. [Figure 4]This figure shows the method for displaying the rail soundness according to the rail soundness calculation method of this embodiment. [Figure 5] A graph showing the relationship between the 5m chord height displacement and the rail's structural integrity. [Modes for carrying out the invention]

[0018] Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. Note that the following embodiments are not intended to limit the invention as described in each claim, and not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention.

[0019] Figure 1 is a flowchart of the rail soundness calculation method according to an embodiment of the present invention; Figure 2 is a diagram showing the waveform used in the rail soundness calculation method according to an embodiment of the present invention; Figure 3 is a detailed flowchart of the rail soundness calculation method according to an embodiment of the present invention; Figure 4 is a diagram showing the display method of the rail soundness calculation method according to this embodiment; and Figure 5 is a graph showing the relationship between the 5m chord height displacement and the rail soundness.

[0020] As shown in Figure 1, the rail condition calculation method according to this embodiment includes a rail condition calculation means that performs a measurement step (S101), a waveform calculation step (S102), a section identification step (S103), a quantity calculation step (S104), and a rail condition calculation step (S105).

[0021] The measurement process (S101) involves measuring the track elevation displacement waveform and axle box acceleration waveform using measuring means installed on a track inspection vehicle or the like. The elevation displacement is measured and evaluated by the relative displacement between three points separated by a certain distance in the longitudinal direction. For example, a method called the 5m chord straight-line method is preferable. The 5m chord straight-line method involves placing a 5m chord against the rail and measuring the distance between the chord and the rail at its center. Furthermore, for the axle box acceleration measurement method, it is preferable to measure acceleration data simultaneously with track displacement data using acceleration sensors installed on the axle box support device of the bogie of the track inspection vehicle.

[0022] The measurement data for vertical displacement and axle box acceleration can be obtained as waveform data as shown in Figures 2(a) and (b).

[0023] The waveform calculation step (S102) calculates the floating sleeper waveform shown in Figure 2(c) from the high and low displacement waveforms measured in the measurement step (S101). A floating sleeper refers to a state in which a gap is created between the bottom surface of the sleeper and the track bed surface, and the floating sleeper waveform is a plot of the fluctuation in the amount of sleeper floating along the kilometer. Various conventional calculation methods can be used to calculate the floating sleeper waveform from the high and low displacement waveforms.

[0024] The section identification step (S103) identifies the peak position in the high / low displacement waveform or floating sleeper waveform that exceeds a predetermined threshold, and identifies a section having a predetermined offset amount centered on that peak position. Specifically, for example, in the high / low displacement waveform in Figure 2(a), a point (P1) that falls below a preset threshold is identified. Then, in the axle box acceleration waveform (see Figure 2(b)) and the floating sleeper waveform (see Figure 2(c)), a section R1 is identified as the starting and ending kilometer points, with a specified offset applied to a position at the same kilometer as P1. In the rail soundness calculation method according to this embodiment, when measuring using the 5m chord straight-arrow method in the measurement step (S101), it is preferable to set the offset to 3m before and after. The offset amount can be appropriately changed depending on the measurement method in the measurement step (S101).

[0025] Furthermore, in cases where sections R2, for example, have adjacent points where the high and low displacement waveforms fall below a threshold, a specified offset amount can be identified from each peak position, and the resulting step-like shape can be created by superimposing these offset amounts from each other's peak positions.

[0026] Subsequently, the maximum and minimum values ​​within the specified interval are determined for the axle box acceleration waveform and the floating sleeper waveform. Specifically, as shown in Figures 2(b) and (c), the maximum value A of the axle box acceleration in interval R1 is determined. max and minimum value Amin and the maximum value F of the floating sleeper waveform max is obtained.

[0027] A quantity calculation step (S104) calculates the amount of sleeper floating calculated from the maximum value F of the floating sleeper waveform in each section specified in the section specifying step (S103), max and the rail irregularity amount calculated from the maximum value A of the axle box acceleration waveform max and the minimum value A min Specifically, as shown in Fig. 3, the height displacement waveform or the axle box acceleration waveform is multiplied by 0 to create a waveform with all sections being 0. Next, for the waveform with all sections being 0, the data within the section specified in the section specifying step (S103) is replaced with respective values of the maximum value F of floating sleeper, max the maximum value A of axle box acceleration max and the minimum value A min Through this replacement, the maximum value F of floating sleeper obtained from floating sleeper and axle box acceleration, which are csv data calculated from the floating sleeper waveform and the axle box acceleration waveform, max and the maximum value A of axle box acceleration, max and the minimum value A min can be used as real number sequence data on the distance axis. Through this processing, even when the floating sleeper waveform and the axle box acceleration waveform refer to different kilometer correspondence tables (tables for associating data numbers with kilometer posts), subsequent calculation can be performed only with data that refers to one of the kilometer correspondence tables, thereby avoiding minute positional displacement and enabling calculation at strictly the same kilometer post.

[0028] Thereafter, the irregularity amount of the rail top surface is calculated from the difference between the maximum value A of axle box acceleration max and the minimum value A min by a conventionally known calculation method. Further, the maximum value F of floating sleeper max is set as the amount of sleeper floating.

[0029] A rail soundness calculation step (S105) first calculates rail stress σ from the amount of sleeper floating and the irregularity amount of the rail top surface m The rail stress σ mWhen the amount of unevenness on the top surface is z (mm), the amount of sleeper lift is d (mm), and a, b, and c are coefficients, σ m It can be calculated from =az+bd+c. Then the calculated rail stress σ m Rail condition f h Calculate the rail condition f. h The fatigue limit of the rail is σ c If we let (MPa), then f h = 1 - σ m / σ c It can be calculated by [method].

[0030] Furthermore, the rail integrity calculation process (S105) is performed by determining the rail integrity f h After determining the structure, as shown in Figure 2(e), the rail soundness of only the sections with structures is extracted using data obtained by converting ledger data such as tunnel data and track bed type and joint data shown in Figure 2(d) into waveform data. Specifically, the waveform created in the quantity calculation process (S104) with all sections set to 0 is modified by replacing the data within tunnel sections and ballast track sections in the ledger with 1, and by multiplying the resulting waveform with the rail soundness waveform, it becomes possible to extract the rail soundness of only the ballast track inside the tunnel. Similarly, by creating a waveform from the ledger data with only the joints set to 1 and the other sections set to 0, it becomes possible to determine the presence or absence of joints in the sections identified in the section identification process (S103), i.e., the sections targeted for rail soundness calculation.

[0031] As mentioned above, rail condition f h Since this can be determined from the amount of sleeper lift and the amount of rail unevenness, it is preferable to calculate the degree of influence of the amount of sleeper lift and the amount of rail unevenness, respectively, and, as shown in Figure 4, to display the areas where rail soundness has deteriorated separately, showing the degree of influence of the amount of rail unevenness and the amount of sleeper lift on rail soundness.

[0032] This makes it possible to determine whether a section where the rail condition has deteriorated and is deemed highly dangerous is largely due to the amount of rail unevenness or the amount of sleeper lifting, and it becomes easier to select a maintenance method, such as grinding the top surface of the rails or maintaining the ballast track.

[0033] Furthermore, the rail soundness calculation method according to this embodiment is preferably performed by a rail soundness calculation system. The rail soundness calculation system includes the above-mentioned measuring means for measuring the track's height displacement waveform and axle box acceleration waveform; waveform calculation means for performing a waveform calculation step (S102) for calculating a floating sleeper waveform from the height displacement waveform; section identification means for performing a section identification step (S103) for identifying a peak position in the height displacement waveform or floating sleeper waveform that exceeds a predetermined threshold, and identifying a section having a predetermined offset amount centered on the peak position; quantity calculation means for performing a quantity calculation step (S104) for calculating the amount of sleeper floating calculated from the maximum value of the floating sleeper waveform in the section, and the amount of rail irregularity calculated from the maximum and minimum values ​​of the axle box acceleration waveform; and rail soundness calculation means for performing a rail soundness calculation step (S105) for calculating rail stress from the amount of sleeper floating and rail irregularity to calculate the rail soundness.

[0034] In the rail condition calculation method according to this embodiment, the waveform calculation step (S102), section identification step (S103), quantity calculation step (S104), and rail condition calculation step (S105) are preferably performed by a processing means (not shown) installed on or on the ground of a railway vehicle. The processing means is preferably a processing device such as a computer. The processing device includes an arithmetic unit such as a CPU (Central Processing Unit) that executes the processing program, a ROM (Read Only Memory) that stores the processing program, and a RAM (Random Access Memory) that temporarily stores data necessary for the CPU's processing. Furthermore, the processing device preferably includes input devices such as a keyboard, mouse, and touch panel, output devices such as a CRT (Cathode-Ray-Tube) display, liquid crystal display, and printer, and a communication interface.

[0035] Such a processing device is preferably a computer system built within a computer, and such a computer is preferably a personal computer, workstation, server, or tablet computer. Various types of computers can be used as long as they operate according to programs such as application software recorded in a storage device, and it may be a single computer or a group of computers connected to each other via a network or other means.

[0036] Thus, according to the rail soundness calculation method and rail soundness calculation system of this embodiment, even if there is a difference in the peak position between the axle box acceleration and the floating sleeper waveform, the rail soundness can be calculated in a simpler and more efficient way without underestimating the rail stress.

[0037] Next, the rail soundness calculation method according to this embodiment was applied to data from a conventional railway line in operation to confirm its effectiveness. First, the outline of the section for which rail soundness was evaluated is as follows: Track length: 59,500 km (single track, ballast track length in tunnels: 16,334 km), Annual tonnage: 1.8 to 3 million tons, Main track structure: 50 kgN rails (standard length), ballast track, PC sleepers. Note that in calculating rail soundness, rail stress σ m This is calculated using a coefficient that assumes a typical express train running on the line in question, and the fatigue limit σ c The pressure was set to 180 MPa, assuming there was 3 mm of corrosion at the bottom of the rail.

[0038] Furthermore, the calculation target section was defined as the range of 3m before and after the negative peak position of the chord height displacement of -7mm or less at 5m. For estimating the amount of rail irregularity, axle box acceleration waveforms with a bandpass filter of wavelength 0.33 to 1.25m were used, and for estimating the amount of sleeper lift, height restoration waveforms with a restoration bandwidth of 3 to 50m were used.

[0039] Based on the rail soundness calculation method according to this embodiment, five locations (points A to E) where rail soundness had deteriorated were selected as subjects for on-site investigation. Visual inspections, measurement of rail irregularities by 1m stretching, and measurement of sleeper lift by loosening the rail fastening device were performed. The results are shown in Table 1 below. In Table 1, the "Examples" column shows the results calculated using the rail soundness calculation method according to this embodiment, while the "Comparative Examples" column shows the results of on-site investigations.

[0040] [Table 1]

[0041] As is clear from Table 1, the amount of sleeper lift in the example was found to be roughly close to that of the comparative example. Regarding the amount of rail irregularities, although there was a slight error, the example and the comparative example were found to be roughly close to each other. From these results, it was confirmed that the rail soundness calculation method according to this embodiment can appropriately evaluate defective areas.

[0042] Next, a comparison was made between the rail soundness calculation method according to this embodiment and the tunnel rail management method using 5m chord height displacement. Figure 5 is a graph showing the relationship between the minimum value of the 5m chord height displacement in the calculation target section and the rail soundness. As shown in Figure 5, there is a high correlation between the 5m chord height displacement and the rail soundness, and the tunnel rail management method using 5m chord height displacement can appropriately grasp the risk of rail breakage to a certain extent. However, at location B, where a large amount of rail irregularity was confirmed in the field survey, the 5m chord height displacement was -8.9 mm, which is a relatively small displacement. It can be seen that the priority of treatment is evaluated relatively low in the conventional tunnel rail management method using 5m chord height displacement.

[0043] Based on the above, the rail soundness calculation method according to this embodiment, which evaluates vehicle running surface irregularities with very short wavelength components (wavelength 3m or less) that cannot be evaluated by height displacement data alone, by estimating the amount of rail irregularity from axle box acceleration, can more accurately assess the risk of rail breakage.

[0044] Furthermore, while the rail soundness calculation method and rail soundness calculation system according to the above embodiment described above have explained the case where structural data and joint data are used as ledger data in the rail soundness calculation process, the method may be applied to the management and analysis of track displacement data, such as extracting track displacement data only from curved sections, rather than being limited to these ledger data. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention. [Explanation of Symbols]

[0045] S101 Measurement process, S102 Waveform calculation process, S103 Section identification process, S104 Quantity calculation process, S105 Rail soundness calculation process.

Claims

1. A measurement process for measuring the vertical displacement waveform and the axle box acceleration waveform of the track, A waveform calculation step for calculating a floating sleeper waveform from the aforementioned high and low displacement waveforms, A section identification step involves identifying the peak position in the high / low displacement waveform or floating sleeper waveform that exceeds a predetermined threshold, and identifying a section having a predetermined offset amount centered on the said peak position. A calculation step for calculating the amount of rail irregularity calculated from the maximum value of the floating sleeper waveform in the aforementioned section, which is the amount of sleeper floating, and the maximum and minimum values ​​of the axle box acceleration waveform, The system includes a rail soundness calculation step which calculates rail stress from the amount of lift of the sleepers and the amount of unevenness in the rails to calculate the rail soundness, The rail soundness calculation step is a rail soundness calculation method characterized by referring to ledger waveform data, which is obtained by converting ledger data of at least one of the tunnel or track bed types into waveform data, to extract rail soundness only within the tunnel, rail soundness only on the ballast track, or rail soundness only on the ballast track inside the tunnel.

2. In the rail condition calculation method described in claim 1, The rail soundness calculation method is characterized in that the quantity calculation step is performed by multiplying the floating sleeper waveform or axle box acceleration waveform by 0 to create a waveform of 0 for the entire section, and then performing a process to replace the data within the section of the waveform of 0 for the entire section with the maximum value of the floating sleeper waveform and the maximum and minimum values ​​of the axle box acceleration waveform.

3. In the rail condition calculation method described in claim 1, The rail soundness calculation step is a rail soundness calculation method characterized by calculating the effects of the amount of sleeper lift and the amount of rail irregularities.

4. A measuring means for measuring the vertical displacement waveform and the axle box acceleration waveform of the track, A waveform calculation means for calculating a floating sleeper waveform from the aforementioned high and low displacement waveforms, A section identification means for identifying a peak position in the aforementioned high / low displacement waveform or floating sleeper waveform that exceeds a predetermined threshold, and for identifying a section having a predetermined offset amount centered on the said peak position, A quantity calculation means for calculating the amount of sleeper floating calculated from the maximum value of the floating sleeper waveform in the aforementioned section, and the amount of rail unevenness calculated from the maximum and minimum values ​​of the axle box acceleration waveform, The system includes a rail soundness calculation means that calculates rail stress from the amount of lift of the sleepers and the amount of unevenness in the rails to calculate the rail soundness, The rail soundness calculation means is characterized by referring to ledger waveform data, which is a waveform data of ledger data of at least one of the tunnel or track bed types, to extract rail soundness only within the tunnel, rail soundness only on the ballast track, or rail soundness only on the ballast track inside the tunnel.

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