Method and machine for tamping a track

Abstract

The invention relates to a method for tamping sleepers (6) of a track panel (7) supported in a ballast bed (5) by a tamping unit (9), which comprises two tamping tools (17) opposite each other, which are subjected to vibrations (22) during tamping of a respective sleeper (6), are lowered into the ballast bed (5) and are moved towards each other by an extrusion movement (30) while the track panel (7) is held in an elevated position. The extrusion speed (v) of at least one tamping tool (17) is monitored by an evaluation device (27), wherein a current value (28) of the extrusion speed (v) is compared to a limit value (29) when a predetermined extrusion time (t1) or a predetermined extrusion distance (s) is reached, and wherein a notification signal (31) indicates whether the current value (28) is higher than the limit value (29). This optionally indicates that a void (24) located below the sleeper (6) has not yet been sufficiently filled.

Description

Technical Field

[0001] This invention relates to a method for tamping sleepers of a track panel supported in a ballast bed by means of a tamping unit comprising two tamping tools opposing each other, which, during the tamping of a respective sleeper, are lowered into the ballast bed under the application of vibration and move toward each other by a squeezing motion while the track panel is held in an elevated position. The invention also relates to a tamping machine for performing this method. Background Technology

[0002] Ballasted railway lines require periodic track alignment, typically using track tamping machines, turnout tamping machines, or general-purpose tamping machines. These machines, which can move along the track in a cyclic or continuous manner, generally include a measuring system, a lifting unit, and a tamping unit. The lifting unit raises the track to the predetermined position. To secure this new layer, the ballast is tamped and compacted from both sides below the corresponding sleepers using tamping tools located on the tamping unit.

[0003] Various designs of tamping units for tamping sleepers supported in a ballast bed are known. For example, AT350 097B discloses a tamping unit with a hydraulic squeeze actuator connected on one side to a rotating eccentric shaft for generating vibration and on the other side to a tiltable tamping tool. A tamping unit with a hydraulic actuator is known from AT 339 358B, which has a combined function, acting as both a squeeze actuator and a vibration generator.

[0004] AT 515 801A4 describes a method for compacting a track ballast bed using a tamping unit; a mass figure for the ballast bed hardness must be specified. For this purpose, the tamping force of the tamping cylinder is recorded based on the tamping distance, and a parameter is defined by the energy consumption derived therefrom. However, this parameter is not very meaningful because it does not account for the non-negligible energy loss in the system. Furthermore, the total energy actually introduced into the ballast during the tamping process cannot reliably assess the condition of the ballast bed.

[0005] In one method known according to AT 520 056A1, for at least one tamping tool, each vibration cycle caused by a vibration actuator is analyzed. Specifically, during the vibration cycle, the order of forces acting on the tamping tool over the distance covered by the tamping tool is recorded. Continuous evaluation of these force-displacement orders allows for real-time detection of the condition of the ballast bed and whether sufficient compaction has been achieved. Summary of the Invention

[0006] The object of this invention is to improve upon the methods of the above type by enabling optimal ballast filling of the gaps under the sleepers in a simple manner. Another object of this invention is to provide a corresponding tamping machine.

[0007] According to the invention, these objectives are achieved by the method according to claim 1 and the machine according to claim 13. Advantageous embodiments of the invention are presented in the dependent claims.

[0008] In this paper, an evaluation device is used to monitor the compaction speed of at least one tamping tool. When a predetermined compaction time or a predetermined compaction distance is reached, the current value of the compaction speed is compared with a limit value, and a notification signal indicates whether the current value exceeds the limit value. During the filling of the voids under the sleepers, a reaction force generated by ballast friction acts on the tamping tool. As the voids are filled, this reaction force increases, and the stiffness of the sleeper bed formed under the sleepers also increases. Consequently, the compaction speed decreases, while the compaction pressure remains constant.

[0009] This invention utilizes this effect to record the current filling status. If the current value of the compression speed remains above the limit value after a predetermined compression stage, corresponding information is output via a notification signal. For example, an optical or acoustic notification signal is output. The current filling status can also be indicated by maintaining the notification signal or by a notification signal that changes upon a change in status. In either case, based on numerical comparison, the notification signal indicates whether the gap beneath the sleeper has been adequately filled or is still insufficiently filled. In the latter case, optimal filling can be achieved through subsequent measures.

[0010] In a simpler variation, a notification signal is fed to the display device to indicate to the operator that the voids under the current sleeper to be tamped are not filled sufficiently. This informs the operator that the current tamping process should continue and that further tamping may be necessary to achieve optimal filling.

[0011] In an improved embodiment of the invention, a notification signal is fed to the control device of the tamping unit, and in particular, the control device automatically specifies a longer compaction duration and / or a modified compaction force. This eliminates the need for operator intervention to optimize ballast filling.

[0012] If necessary, it is useful for the control device to automatically trigger a further tamping process on the current sleeper to be tamped. This measure is particularly advantageous if the available tamping distance of the tamping tool is insufficient to achieve the desired filling state.

[0013] A further advantageous improvement of the invention is that the vibration frequency of the tamping tool is increased when the current value is below a limit value. To this end, the current value is continuously compared with the limit value to record the achievement of the optimal filling state. Only when this optimal filling state is achieved will the vibration transmitted from the tamping tool to the ballast increase the temporary dynamic fluidization of the ballast due to the increased vibration frequency. This so-called ballast flow allows ballast particles to slide against each other with low friction. The ballast behaves similarly to a fluid and vibrates independently to higher layer densities. During the filling phase, this effect is limited due to the lower vibration frequency. Because the tamping tool moves larger interlocking ballast units, the friction maintained between ballast particles is beneficial to the filling process. Flow around the tamping tool is prevented.

[0014] To compare with the limit value, it is useful to evaluate the current value of the extrusion speed at the point in time when a predetermined extrusion time or predetermined extrusion distance is reached. In this variation, since it is not necessary to modify the recorded speed value, the high computing power of the evaluation device is not required.

[0015] In another variation, it can be advantageous to evaluate the average extrusion speed over the extrusion time or extrusion distance range as the current value. This compensates for inaccuracies when recording speed or irregularities during the extrusion process.

[0016] Another variation offers the option of determining the current value as the result of a weighted time integral or a weighted distance integral. Determining the current value as a weighted sum of several measurements of the extrusion rate requires less computational power. These measures also compensate for the irregularities in the extrusion process, where certain stages of the process are emphasized through appropriate weighting.

[0017] In these improved variations, weights are predefined based on process parameters calculated or measured during the tamping process. This special weighting allows the evaluation algorithm to be automatically adjusted according to changing tamping conditions.

[0018] Advantageously, the penetration work or penetration force is determined as a process parameter during the tamping tool's descent. Based on this process parameter, an adjustment weight is subsequently derived to form the current value of the extrusion speed.

[0019] Further improvements in evaluation are achieved when time series of extrusion speed or extrusion distance are fed as input data into a machine learning model. For example, neural networks, support vector machines, decision trees, regression analysis, or Bayesian networks can be incorporated into the evaluation apparatus. Other process parameters, such as the rise in gauge length or the desired extrusion pressure, can also be used as input data for the model. The model's output provides current values ​​that can be used to evaluate the filling state.

[0020] The tamping machine according to the invention for performing any of the methods includes a lifting unit for lifting the track panel and a tamping unit for tamping the lifted sleepers. Herein, a sensor system is arranged to record the compaction speed, wherein the sensor system is coupled to an evaluation device. An algorithm for comparing the current value of the compaction speed with a limit value is provided in the evaluation device. Furthermore, the evaluation device is configured to output a notification signal indicating whether the current value is higher than the limit value at a predetermined comparison time. The tamping machine designed in this way can optimally fill the gaps formed under the lifted sleepers in a simple manner.

[0021] In a further simple improvement, the evaluation device is coupled with a display device for showing notifications. The display alerts the operator to insufficient fill status, thereby initiating necessary follow-up actions.

[0022] In further improvements to the machine, the evaluation device is coupled with the control unit of the tamping unit. Once the control unit receives information about insufficient filling from a notification signal, it automatically initiates measures to further fill the gaps. For example, it may extend the compaction time or perform a further tamping process on the sleeper currently to be tamped. Attached Figure Description

[0023] The invention will be explained illustratively below with reference to the accompanying drawings. The following drawings schematically illustrate:

[0024] Figure 1 A tamping machine is shown;

[0025] Figure 2 The tamping unit is shown during the descent process;

[0026] Figure 3 The tamping tool used in the void filling process is shown;

[0027] Figure 4 The tamping tools used in the compaction process of the pillow bed are shown;

[0028] Figure 5 A schematic diagram showing the change of extrusion speed over time is shown;

[0029] Figure 6 The determination of the limit value is shown;

[0030] Figure 7 The determination of the limit values ​​and the evaluation of the measured extrusion speed are shown. Detailed Implementation

[0031] Figure 1The tamping machine 1 shown is movable on the rails 3 of the track 4 via a rail-based traveling device 2. Sleepers 6, supported in the ballast bed 5, together with the rails 3 fixed to the sleepers 6, form a track panel 7. To perform this method, the tamping machine 1 includes a lifting unit 8 and a tamping unit 9. Furthermore, a measuring system 10 is arranged for correcting the track position. Units 8 and 9 can be adjusted relative to the frame 12 via an actuation drive 11. Advantageously, the lifting unit 8 is also provided to laterally pull the track panel 7.

[0032] Figure 2 The diagram shows the processing sections of the tamping unit 9 and track 4. The tamping tool holder 14 is vertically guided within the tamping unit frame 13. A driven eccentric shaft, acting as a vibration actuator 15, is arranged on the tamping tool holder 14. Two compression actuators 16 are linked to the eccentric shaft. Rotation of the eccentric shaft causes the compression actuators 16 to vibrate, with the corresponding eccentricity determining the vibration amplitude.

[0033] On the tamping tool bracket 14, tamping tools 17 are mounted opposite each other to the sleepers 6 to be tamped. Each tamping tool 17 includes a tamping rod 18, the upper arm of which is connected to an associated actuation drive 16. A tamping pick 19 penetrates the ballast bed 5 during tamping and is positioned on the lower arm.

[0034] Figure 2 The tamping unit 9 is shown during the descent movement 20 of the tamping tool 17, where the tamping pick 19 applies a penetrating force 21 to the ballast bed 5. During this process, the vibration driver 15 is activated, causing vibration 22 to be applied to the corresponding tamping pick 19 via the associated tamping rod 18 and the resisted compression driver 16. The treated section of the track panel 7 is lifted to a predetermined target position by the lifting unit 8 with a lifting force 23. During this process, gaps 24 are formed under the sleepers 6 still to be tamped, which are filled with ballast during tamping. The roller clamps 25 of the lifting unit 8 hold the treated track panel 7 in place until the corresponding tamping process is completed.

[0035] A sensor 26 for recording the extrusion speed ν is arranged on at least one tamping tool 17. This sensor system 26 is coupled to an evaluation device 27 to compare the current value 28 of the extrusion speed ν with a stored limit value (threshold) 29. This comparison is performed continuously or at least at some point after the extrusion motion 30 has begun. In any case, the result of this comparison, performed when a predetermined extrusion time t1 or a predetermined extrusion distance s is reached, is subsequently relevant. For this purpose, corresponding default values ​​for the extrusion time t and / or extrusion distance s are stored in the evaluation device 27. When this default value is reached, the extrusion motion is typically not yet complete. The planned total extrusion time or planned total extrusion distance is greater than the default value associated with the value comparison.

[0036] If the relevant value comparison shows that the current value 28 of the compaction speed ν is still higher than the limit value 29, a corresponding notification signal 31 is output through the evaluation device 27. This indicates that the gaps 24 of the currently tamped sleepers 6 have not been fully filled. The operator receives the corresponding information through the display device 32 that receives the notification signal 31. In this way, the operator can initiate measures to optimize the filling of the gaps 24.

[0037] The evaluation device 27 is coupled to the control device 33 of the tamping unit 9 for automatically implementing corresponding measures. First, a notification signal 31 actuates the tamping drive 16 via the control device 33 to continue the tamping motion. The current value 28 of the tamping speed ν is continuously checked to ensure it has reached its limit value 29. The maximum possible tamping distance limits this measure. Furthermore, reservation is necessary to ensure that the ballast pushed under the sleepers 6 during filling is eventually compacted. If necessary, the same sleepers 6 are tamped again as a further measure to ensure optimal filling of the gaps 24. The process is then checked again by comparing the current value 28 and the limit value 29 of the tamping speed ν.

[0038] Shortly before the tamping pick 19 reaches the predetermined penetration depth, the tamping motion 30 begins with the corresponding actuation of the tamping drive 16. First, the tamping process fills the gap 24 beneath the sleeper 6, as... Figure 3 As shown. During this process, because a constant pressure is applied to the extrusion actuator 16, which is designed as a hydraulic cylinder, the tamping pick 19 applies a constant extrusion force 34 to the ballast particles.

[0039] During the filling of voids 24, vibration 22 is still applied to the tamping tool 17, at a lower frequency advantageously compared to the frequency during penetration into the ballast bed 5. In this way, the ballast particles remain in motion. The lower frequency prevents excessive fluidization of the ballast particles, thus preventing lateral drift of the ballast particles.

[0040] The start of the extrusion motion 30 is recorded in the evaluation device 27 so that the current value 28 of the extrusion speed ν is compared with the stored limit value 29 when the predetermined extrusion time t1 is reached. The limit value 29 is predetermined through theoretical analysis, simulation or testing and stored in the evaluation device 27.

[0041] One possibility for determining the limit value 29 through testing is to raise track panel 7 by the desired amount before the actual tamping process begins. In the first step 35, track panel 7 is raised, as follows: Figure 6As shown. During the pressing process, the pressing speed ν is measured in the second step 36, and the pressing force 34 is measured if necessary. Furthermore, in the third step 37, the time point t0 is determined using the measurement of the lifting force 23, from which the sleeper 6 is pushed upwards as the gap 24 is fully filled. At time point t0, the lifting force 23 decreases, and the pressing speed ν decreases. The limit value 29 used to identify whether the filling process is complete corresponds in this example to the speed ν measured when filling is achieved.

[0042] Optimal filling of voids 24 is achieved in each compaction process by continuously comparing the current value 28 and the limit value 29 of the compaction speed ν. Advantageously, the frequency of vibration 22 of the tamping tool 17 begins to increase from this point. The increased dynamic excitation increases the mobility of the ballast particles, thus transforming them into a denser structure. In this way, optimal compaction of the ballast pushed under the sleeper 6 is achieved in the final stage of the compaction process. The transition from filling frequency to compaction frequency can also be based solely on distance or solely on time. As described above, the corresponding threshold is determined in advance based on experience by measuring the lifting force 23.

[0043] In a further improvement of the invention, the limit value 29 and / or the time point t1 for comparison with the current value 28 of the compaction speed ν are determined based on other calculated or measured process parameters. Such process parameters are, for example, the penetration force 21 or penetration work during the descent of the tamping pick 19 into the ballast bed 5. The lifting of the track panel 7 by means of the lifting unit 8 and the desired compaction force 34 can also be used as process parameters affecting the limit value 29 or the comparison time t1.

[0044] Furthermore, determining the average speed as the current value 28 of the extrusion speed ν can be useful. The extrusion speed ν is recorded from the start of the extrusion process, and the average value is calculated continuously. For example, the average speed can be determined by weighted time integration or weighted distance integration, or by a weighted sum of several speed measurements. The weighting can be based on time or distance and can be defined according to the process parameters mentioned above. If the current value 28 determined in this way is higher than the limit value 29, incomplete filling is detected.

[0045] The final compaction process of the filled ballast is as follows: 38 Figure 4 As shown. This process occurs only after the upstream filling process 39 has been completed. Because the resistance of the ballast during filling is lower than that of the filled ballast, the speed v of the extrusion motion 30 during filling is greater than the speed during the final compaction of the filled ballast under a constant extrusion pressure 34.

[0046] The corresponding velocity order is as follows Figure 5As shown. At time point t0, when the gap 24 under the sleeper 6 is completely filled, a predetermined limit value 29 is determined. In the first example of the compression process, the current value 28 of the compression speed ν is compared with the limit value 29 at a predetermined compression time t1. This first example shows that the current value 28 is still higher than the limit value 29. This is related to the information that the filling process 39 has not yet been completed. In the second example, because a longer compression time is predetermined, the comparison is made at a later time point t1'. Here, the current value 28 is already lower than the limit value 29. This comparison provides information that the filling process 39 has been completed.

[0047] For example, the speed ν can be measured or estimated by measuring the extrusion distance of the extrusion cylinder 16, by measuring the rotation angle of the tamping rod 18, or by measuring the volumetric flow rate of the extrusion cylinder 16 or several extrusion cylinders 16. In a further improvement of the invention, the order of the measured or estimated extrusion speed ν is used as an input parameter for a machine learning model. For example, a neural network, support vector machine, decision tree, regression analysis algorithm, or Bayesian network can be set in the evaluation device 27.

[0048] Figure 7 A simple evaluation using evaluation device 27 is shown. As described above, a limit value 29 is predetermined and stored. The extrusion speed ν is recorded in each extrusion process 40. In comparison process 41, the current value 28 of the extrusion speed ν is compared with the stored limit value 29. Thus, it is automatically determined whether the current filling process 39 is complete. In the case of insufficient filling, a corresponding notification signal 31 is output.

[0049] This ensures optimal tamping for each sleeper 6. Tamping of the next sleeper 6 is only performed in the working direction 42 after the gap 24 under the corresponding sleeper 6 has been completely filled and the compaction of the filling ballast has been completed. The process is advantageously automated because the control device 33 reports to the machine controller that the tamping process is complete. Therefore, the machine 1 or so-called auxiliary device moves forward by one sleeper spacing, or, in the case of a multi-sleeper tamping unit 9, by several sleeper spacings.

[0050] If necessary, the tamping process may be interrupted after a predetermined number of tamping cycles or in the event of a significant change in conditions, in order to re-determine the limit value 29. This may be useful, for example, if a new ballast layer is being transitioned to an older ballast layer or if the type of sleeper 6 changes. Otherwise, common changes in track conditions are compensated for by weighting the determined process parameters as described.

Claims

1. A method for tamping sleepers (6) of a track panel (7) supported in a ballast bed (5) by means of a tamping unit (9), the tamping unit comprising two tamping tools (17) facing each other, which, during the tamping of the respective sleepers (6), descend into the ballast bed (5) under the application of vibration (22), and move toward each other by a squeezing motion (30) while the track panel (7) is held in an elevated position, characterized in that, An evaluation device (27) is used to monitor the compression speed (ν) of at least one tamping tool (17). When a predetermined compression time (t1) or a predetermined compression distance (s) is reached, the current value (28) of the compression speed (ν) is compared with a limit value (29), and a notification signal (31) indicates whether the current value (28) is higher than the limit value (29).

2. The method according to claim 1, characterized in that, The notification signal (31) is fed to the display device (32) to indicate to the operator that the gap (24) under the current sleeper (6) to be tamped is not filled.

3. The method according to claim 1 or 2, characterized in that, The notification signal (31) is fed to the control device (33) of the tamping unit (9), and a longer tamping duration and / or a modified tamping force (34) are automatically specified.

4. The method according to claim 3, characterized in that, The longer extrusion duration and / or the modified extrusion force (34) are automatically specified by the control device (33).

5. The method according to claim 3, characterized in that, The control device (33) automatically triggers a further tamping process for the current sleeper (6) to be tamped.

6. The method according to claim 1 or 2, characterized in that, When the current value (28) is lower than the limit value (29), the frequency of the vibration (22) of the tamping tool (17) is increased.

7. The method according to claim 1 or 2, characterized in that, The extrusion speed (ν) at the point in time when the predetermined extrusion time (t1) or the predetermined extrusion distance (s) is evaluated as the current value (28).

8. The method according to claim 1 or 2, characterized in that, The average value of the extrusion speed (ν) within the range of extrusion time (t) or extrusion distance (s) is evaluated as the current value (28).

9. The method according to claim 1 or 2, characterized in that, The current value (28) is determined as the result of the weighted time integral or the weighted distance integral.

10. The method according to claim 1 or 2, characterized in that, The current value (28) is determined as a weighted sum of several measurements of the extrusion speed (ν).

11. The method according to claim 9 or 10, characterized in that, Weights are predefined based on the calculated or measured process parameters of the tamping process.

12. The method according to claim 11, characterized in that, During the descent of the tamping tool (17), the penetration work or penetration force (21) is recorded as a process parameter.

13. The method according to claim 1 or 2, characterized in that, The time series of extrusion speed (ν) or extrusion distance (s) is fed into the machine learning model as input data.

14. A tamping machine (1) for performing the method according to any one of claims 1 to 13, the tamping machine (1) comprising a lifting unit (8) for lifting a track panel (7) and a tamping unit (9) for tamping the lifted sleepers (6), characterized in that, A sensor system (26) is arranged to record the extrusion speed (ν), and the sensor system (26) is coupled to an evaluation device (27), which is configured to compare the current value (28) of the extrusion speed (ν) with a limit value (29) and to output a notification signal (31) indicating whether the current value (28) is higher than the limit value (29).

15. The tamping machine (1) according to claim 14, characterized in that, The evaluation device (27) is coupled to a display device (32) for displaying notifications.

16. The tamping machine (1) according to claim 14 or 15, characterized in that, The evaluation device (27) is coupled to the control device (33) of the tamping unit (9).

Images