METHOD AND SYSTEM FOR CORRECTING VERTICAL POSITIONING ERRORS OF A TRACK

Description

Technical area

[0001] The invention relates to a method for correcting vertical track position errors after a lifting and tamping process, with a stabilization process carried out by means of a dynamic track stabilizer, in which a stabilization unit acts on the track at a work point moving forward in a working direction. Before the lifting and tamping process, track position data of the unworked track is recorded, and after the lifting and tamping process, track position data of the tamped track is recorded at a measuring point located upstream of the stabilization unit in the working direction. Furthermore, the invention relates to a system for implementing the method. State of the art

[0002] From WO 2006 / 056215 A1 a method for correcting vertical position errors (elevation errors) of a track with ballast is known, whereby the track is tamped by lifting it into a preliminary target position and then, as part of a track stabilization process, is lowered in a controlled manner into a final target position by applying a static load in conjunction with transverse vibrations.

[0003] During the lifting and tamping process, a targeted elevation of the track is specified in relation to the track elevation errors, allowing track sections with larger elevation errors to be more strongly compacted during subsequent track stabilization. This is intended to counteract rapid subsidence due to traffic loads into the old, faulty track elevation.

[0004] This well-known method is commonly referred to as "design overlift," in which a specific overlift value is specified based on empirical data. This allows for the sustainable correction of individual errors. However, this approach results in unnecessarily strong overlift in some processing zones, with the associated increased demand for ballast.

[0005] AT 519317 A1 discloses a modified method in which, prior to a lifting and tamping process, a smoothed actual track position profile is created from the actual track position of the untreated track. The respective overlift value is subsequently specified based on this actual track position profile relative to the approximately smoothed actual track position profile. In this method, only short-wave track geometry errors are processed with an overlift value. Long-wave settlements are ignored when specifying the overlift value.

[0006] EP 0 952 254 A1 describes another method for track alignment correction using a dynamic track stabilizer. The track stabilizer is operated with a variable static load to eliminate long-wave track alignment errors after a lifting and tamping process. Based on a measurement of the tamped track, a new target track position is calculated, with correction values ​​derived from this determining the change in the static load. A similar method is known from WO 2020 / 177967 A1, whereby a dynamic track stabilizer can achieve increased track subsidence by removing ballast from the end faces of the sleepers using a respective lateral clearing device. Description of the invention

[0007] The invention is based on the object of improving a method of the type mentioned above over the prior art in such a way that, after the stabilization process, an optimal track position is achieved regardless of the type and extent of existing track defects. Furthermore, it is an object of the invention to provide a corresponding system.

[0008] According to the invention, these objects are achieved by the features of independent claims 1 and 8. Advantageous developments of the invention emerge from the dependent claims.

[0009] At a final measurement point located downstream of the stabilization unit in the working direction, additional track position data of the stabilized, lowered track is recorded outside the influence of the stabilization unit. During the stabilization process, the dynamic track stabilizer is controlled based on the track position data of the untreated and tamped track at the work site and the track position data of the stabilized, lowered track at the final measurement point. Together with the measurements before and after the lifting and tamping process, the additional final measurement of the track position after the stabilization process enables precise control of the dynamic track stabilizer. Specifically, the track position measured before and after the lifting and tamping process, together with the track position measured after the stabilization process, are used as the basis for the controlled control of the dynamic track stabilizer.In this way, residual errors tend to zero after an initial settling phase, resulting in optimal track alignment. Residual errors detected, particularly after the lifting and tamping process, are eliminated by the controlled control of the dynamic track stabilizer.

[0010] In a further development of the process, track position data for a final target position of the track are specified, whereby the dynamic track stabilizer is additionally controlled during the stabilization process based on correction data derived for the work site from the target position data and the track position data of the unworked track. Thus, measurement data from individual errors and other pronounced position errors of the unworked track are directly incorporated into the control of the dynamic track stabilizer, thereby proactively minimizing control deviations. This process extension actively compensates for uneven overlifts through the upstream lifting and tamping process with design overlift.

[0011] To record track position data, a longitudinal inclination or longitudinal height and a transverse inclination or superelevation of the track are advantageously measured at each measuring point. In a curve, the longitudinal inclination or longitudinal height of an inner rail is preferably recorded. Relative to this, the transverse inclination or superelevation indicates the position of an outer rail. Thus, the vertical positions (elevations) of both rails of the track in different processing states are recorded as track position data.

[0012] In an advantageous embodiment of the method, at least one of the following operating parameters of the dynamic track stabilizer is changed during the stabilization process depending on the recorded track position data: an oscillation frequency of the stabilization unit, a travel speed of the dynamic track stabilizer, a load of the stabilization unit acting on a left rail of the track, a load of the stabilization unit acting on a right rail of the track and a total load acting from the stabilization unit on the track.

[0013] The stabilization process is logically initiated with a predefined initial value for the respective operating parameter, whereby an adjusted value is continuously calculated for the respective operating parameter during the stabilization process using an algorithm installed in a computing unit. The continuous recalculation of the variable operating parameter results in an immediate adaptation of the stabilization process to various system-specific or external influences.

[0014] Preferably, weighting factors are stored in the algorithm for the respective operating parameter, with the weighting factors being continuously adjusted by means of a control system. For example, a formula with its own weighting factors is implemented in the computing unit for each variable operating parameter. The controlled activation of the dynamic track stabilizer is then achieved simply by continuously adjusting the weighting factors. Such an algorithm enables high-quality control because the characteristics of the current controlled system and the dynamics of the control are specified separately. Each operating parameter formula maps the specific interaction between the respective operating parameter and the recorded track position data. A stored adjustment logic for the weighting factors determines the control dynamics.

[0015] According to the invention, a track position measuring system comprising several measuring devices is carried along with the dynamic track stabilizer, wherein the corresponding track position is recorded at the respective measuring point using the assigned measuring devices with respect to a common reference system. In this way, the track position data of the track position changing during processing is collected while the dynamic track stabilizer advances. A track point under consideration is initially located in front of the stabilization unit, where the track position is recorded after the lifting and tamping process. Due to the forward movement of the dynamic track stabilizer, the same track point becomes the current work point during the controlled lowering of the track by the stabilization unit, with a measuring point immediately behind it. In a double unit, this measuring point is preferably located between two stabilization unit units.Outside the influence of the stabilization unit, the track position data of the lowered track position are recorded at the final measurement point. Thus, each measurement point corresponds to a track section under consideration in a chronological sequence during a work run.

[0016] In a further development of this improvement, the reference system is formed by a camera attached to one of the measuring devices and a reference mark attached to another measuring device and positioned within the camera's recording range. In order to record the track position data, the camera records measurement marks attached to the remaining measuring devices. Such an optical measuring system delivers precise measurement results for multiple measuring points, with the shared reference system simplifying further processing of the acquired track position data. In a useful further development, a reference mark is attached directly to the stabilization unit. The corresponding measuring point thus coincides with the work point. The vibration amplitudes of the stabilization unit are then also recorded using the camera. This additional measured variable can be used as an additional parameter for controlling the stabilization process.

[0017] The system according to the invention for carrying out one of the described methods comprises a track position measuring system and a dynamic track stabilizer with a stabilization unit for correcting vertical position errors at a forward-moving work point of a track, wherein the track position measuring system is set up to detect the track position at a measuring point upstream of the dynamic track stabilizer in the working direction and at a final measuring point downstream of the dynamic track stabilizer in the working direction and located outside the sphere of influence of the stabilization unit, wherein the dynamic track stabilizer comprises a control device to which track position data detected by means of the track position measuring system are fed, and wherein the control device for controlling the dynamic track stabilizer depending on the track position data assigned to the work point and the track position data of the stabilized track assigned to the final measuring point,lowered track outside the influence area of ​​the stabilization unit.

[0018] Advantageously, the control device comprises a computing unit in which an algorithm for recalculating at least one operating parameter of the dynamic track stabilizer is implemented based on continuously updated track position data. Thus, detected track position errors lead to an adjustment of the control of the dynamic track stabilizer almost in real time. The short response time results in a further improvement in the quality of the corrected track position.

[0019] The distance between the work site and the final measurement point is advantageously between 3 m and 10 m, especially between 5 m and 8 m. This ensures that an undisturbed actual track position is determined at the final measurement point after the stabilization process. In this way, the final measurement provides particularly precise data for a control loop controlling the dynamic track stabilizer. The final measurement point follows the work site at a sufficiently close distance to allow rapid control adjustments to be made if necessary.

[0020] In a further development of the system, the stabilization unit comprises a vibration generator and roller clamps that can be clamped to the track rails. The stabilization unit is supported against a machine frame with separately controllable load drives. This improvement allows different loads to be applied to a left and right rail of the track. This enables precise coordination of the depressions achieved with the stabilization unit, ensuring that the specified transverse gradient or camber of the track is precisely achieved.

[0021] An advantageous extension of the system relates to a machine network in which a tamping machine is arranged directly upstream of the dynamic track stabilizer in the working direction, and wherein the track position measuring system comprises at least one measuring device assigned to the tamping machine. With a continuously operating track tamping machine, there is the option of permanent coupling with the dynamic track stabilizer. A cyclically operating tamping machine and a dynamic track stabilizer traveling behind it are operated without mechanical coupling. In both variants, the expanded track position measuring system also extends to measuring points on the tamping machine, so that additional track position data is directly available for controlling the dynamic track stabilizer.

[0022] Advantageously, the track position measuring system comprises a first measuring device to which a camera is mounted, a second measuring device having a reference mark mounted on it, and at least one further measuring device with a reference mark mounted between the first and second measuring devices. Such an optical measuring arrangement delivers precise measurement results even over long distances, while interference caused by vibrations can be specifically filtered out.

[0023] A further improvement to this track position measurement system includes a flashlight that can be controlled together with the camera. This allows the illumination of the reference and measurement marks to be coordinated with the camera's exposure time, thus suppressing interference from sunlight or other light sources. Short description of the drawings

[0024] The invention is explained below by way of example with reference to the accompanying figures. They show schematically: Fig. 1 Dynamic track stabilizer behind a tamping machine Fig. 2 Track position measuring system with five measuring devices in a top view Fig. 3 Stabilization unit with machine frame and track in a sectional view Fig. 4 Optical measuring arrangement with passive markers Fig. 5 Optical measuring arrangement with active markers Fig. 6 Optical measuring arrangement with redundant markers Description of the embodiments

[0025] One in Fig. 1 The dynamic track stabilizer (DGS) 1 shown is an independent track construction machine with a machine frame 2 that is supported on rail bogies 3 and can be moved along a track 4. In the example described, this dynamic track stabilizer 1 is operated together with a tamping machine 5. However, the invention also relates to a method in which the dynamic track stabilizer 1 is used independently of a tamping machine 5.

[0026] In a variant not shown, the tamping machine 5 and the dynamic track stabilizer 1 form a combined track maintenance machine. The cyclical forward movement of a tamping unit 6 is adapted to the continuous forward movement of the dynamic track stabilizer 1, for example, via a longitudinally displaceable auxiliary frame (satellite).

[0027] The Fig. 1 The cyclically operating tamping machine 5 shown is positioned in front of the dynamic track stabilizer 1 with respect to a working direction 7. An exaggerated progression of a track position changing during the working process serves to better illustrate this. A front rail bogie 3 of the tamping machine 1 travels on the untreated track 4. In front of it, a measuring device 8 is guided to record the actual position of this untreated track section. This measuring device 8 is an element of a track position measuring system 9 for recording track position data at various measuring points 10. In addition or in an alternative embodiment of the method, track position data of the untreated track 4 is recorded using a separate track measuring vehicle.

[0028] In the example according to Fig. 1 A measuring system 9 with measuring chords is assigned to the tamping machine 1 as a reference system. The dynamic track stabilizer 1 comprises another measuring system 9 with its own measuring chords. When machines 1, 5 are operated in conjunction, these two measuring systems 9 are combined into a common track position measuring system 9. Advantageously, all recorded track position data is processed by a common evaluation device 11. If necessary, data is transmitted between the tamping machine 5 and the dynamic track stabilizer 1 via an air interface.

[0029] In Subsequently, the track position data are fed to a control device 12 for adaptive control of the dynamic track stabilizer 1. Any track position data of the unprocessed or already tamped track 4 recorded by a separate track measuring vehicle are transmitted in advance to the control device 12 or via a radio link.

[0030] During a lifting and tamping process, a track grid consisting of sleepers 13 and rails 14 attached to them is lifted from a ballast bed 15. For this purpose, the tamping machine 5 comprises a lifting unit 16, which is arranged in front of the tamping unit 6. Between these two units is a further measuring device 8 for recording the lifting 17 performed. In the raised track position, tamping picks of the tamping unit 6 penetrate the ballast bed 15. Under vibration, a setting movement occurs, during which ballast is pushed under the raised sleepers 13 and compacted. In this way, the track 4 is temporarily fixed in a raised track position.

[0031] In the illustrated variant, each measuring device 8 is designed as a rail-guided device. The respective device 8 comprises flanged rollers pressed against the inner sides of the rails 14 by means of a spreading axis. A non-contact variant of the respective measuring device 8 comprises a support on which measuring sensors (e.g., laser scanners) directed toward the rails 14 are arranged. These sensors detect the position of the measuring device 8 relative to the rails 14.

[0032] At the last measuring point 10 of the track position measuring system 9 of the tamping machine 1 in the working direction 7, for example, there is a measuring device 8 with an inertial measuring unit (IMU) 18. This is arranged on a measuring frame 19, which is guided on the rails 14 by four flanged rollers. This measuring device 8 records track position data of the tamped track 4 in a known manner. At the same time, the measuring device 8 serves as the rear reference unit of a chord measuring system mounted on the tamping machine 5.

[0033] The over-lifted track position is lowered to a final target track position 20 in a subsequent stabilization process. This is where the dynamic track stabilizer 1 comes into play. The dynamic track stabilizer 1 is controlled based on measurement data recorded at several measuring points 10, including a final measurement point 21. Specifically, the dynamic track stabilizer 1 performs a controlled lowering of the track 4 at a work point 22 that moves forward with the machine 1 in the working direction 7.

[0034] At this work station 22, a stabilization unit 23 with rolling clamps 24 is clamped onto the rails 14 ( Fig. 3 ). At a predetermined frequency, a vibration generator 25 arranged on the stabilization unit 23 causes the track grid in the area of ​​the work station 22 to vibrate horizontally. The stabilization unit 23 is supported relative to the machine frame 2 by means of load drives 26, each of which is assigned to the rail 14 located below it. These load drives 26 are designed, for example, as separately controllable hydraulic cylinders. By changing the pressure, the static load, which acts on the assigned rail 14 via flanged rollers 27 of the stabilization unit 23, can be changed. A measuring device 8 is arranged directly behind the work station 22 in order to record the currently performed track subsidence.

[0035] In a track position measuring system 9 designed as a chord measuring system, this measuring device 8 serves, on the one hand, to control the lowering of the track 4 and, on the other hand, to remeasure the undisturbed actual track position 28 after stabilization. In the example shown, a total of four measuring devices 8 are arranged on the dynamic track stabilizer 1. Viewed from the front, the first measuring device 8 is guided along a track section with an over-raised track position. The second measuring device 8 is located directly behind the stabilization unit 23. Behind it, the third and fourth measuring devices 8 are arranged at defined distances from one another.

[0036] The four measuring devices 8, together with corresponding measuring chords, form two three-point measuring systems. To control the subsidence, a chord is stretched over each rail 14 between the first and third measuring devices 8. The reference system for the final measurement of the undisturbed track 4 is formed by measuring chords stretched between the second and fourth measuring devices 8. On the measuring device 8 positioned between them, the distance (arrow height) to the assigned measuring chord is measured, and the track position is derived from this according to the well-known traveling chord measuring principle. The position of the third measuring device 8 defines the final measurement point 21. In order to precisely record the position of the undisturbed track 4, a distance a between the final measurement point 21 and the work point 22 is, for example, 6 m. Alternatively, the third measuring device 8 is designed as a measuring carriage with an inertial measuring unit 18 arranged on a measuring frame 19.In this case, the final measurement is carried out using only this adapted measuring device 8.

[0037] The stabilization unit 23 is designed either as a single unit or as a double unit. A double unit comprises two almost identically constructed unit units, arranged one behind the other on track 4. Fig. 1 Such a second unit is shown in dotted lines. With a double unit, vibrations of different directions can be introduced into track 4 simultaneously, resulting in more variable operating parameters than with a single unit.

[0038] According to the invention, at least one operating parameter of the dynamic track stabilizer 1 is changed depending on the track position data acquired during a stabilization process. The acquisition of track position data at several measuring points 10, 21, namely at the measuring points 10 upstream of the stabilization unit 23 and at a subsequent measuring point 21 downstream of the stabilization unit 23, is essential. In the example according to Fig. 1 The corresponding measurements are carried out using the described three-point measuring systems and the inertial measuring unit 18.

[0039] In an improved variant, the measurement of the track position changing during the work process is carried out by means of an optical measuring system 9, as in Fig. 2 shown. The advantage of this variant is a common reference system for all measurements performed. With respect to the working direction 7, a rear measuring device 8 comprises a camera 29 which is directed at all measuring devices 8 in front of it. On each of these measuring devices 8 in front of it, a measuring mark 30 is arranged, one of which is defined as the reference mark 30. A virtual optical chord 31 stretches between the reference mark 30 and the camera 29 and serves as a reference basis for the position of the remaining measuring marks 30. All marks 30 of the measuring system 9 lie in a recording area 32 of the camera 29. The respective measuring or reference mark 30 comprises, for example, a crosshair on a reflective surface.

[0040] In the evaluation device 11 of the track position measuring system 9, the images from the camera 29 are continuously evaluated. The distances between the measuring devices 8 and the image scale of the camera 29 are known. Using these known size ratios, the evaluation device 11 calculates an actual change in position of the measuring mark 30 relative to the optical chord 31 from a displacement of a measuring mark 30 imaged on an image sensor. In a given coordinate system x, y, z, corresponding displacement values ​​Δx, Δy ( Fig. 4 ). These calculated displacement values ​​Δx, Δy correspond to arrow height values ​​measured with a conventional chord measuring system.

[0041] Advantageously, camera 29 is configured to capture monochrome images to optimize analysis. The image sensor's resolution is 5 megapixels, for example. This allows displacements of the measurement marks 30 to be detected in millimeters. A recording frequency of approximately 200 Hz ensures that changes in position are detected immediately. This results in approximately 200 measurements per second.

[0042] In an advantageous further development, the camera 29 is coupled to a flashlight 33. For example, several high-performance LEDs are arranged around a lens of the camera 29 in order to flash in the direction of the measuring marks 30 synchronously with the triggering of the camera 29. In this embodiment, the measuring marks 30 are designed as passive elements of the track position measuring system 9 ( Fig. 4 ). For example, the respective measuring mark 30 is glued as a retroreflective foil to a suitable surface of the associated measuring device 8.

[0043] In Fig. 5 Active measuring marks 30 are shown. These are controlled together with the camera 29 and illuminate in the direction of the camera 29.

[0044] High-performance LEDs are also preferably used here, which flash synchronously with the shutter release of the camera 29. The respective measuring mark 30 comprises a transparent foil, which is backlit with diffuse light by an LED flash 33. Compared to a passive measuring mark, a higher light intensity can be achieved, which allows for better results, especially in dusty environments and poor weather conditions.

[0045] A further improvement of the track position measuring system 9 used in the present invention is described in Fig. 6This takes into account that, in exceptional cases, obstacles 34 may be located between the camera 29 and the measuring marks 30. For example, in the case of significant deflections in track curves, individual components may temporarily obscure the respective viewing axis. Several redundant measuring marks 30 are assigned to a measuring device 8 here, so that the position of the measuring device 8 can be reliably recorded even if one of the measuring marks 30 does not appear in the image taken by the camera 29.

[0046] Based on the recorded track position data, the following operating parameters of the dynamic track stabilizer 1 are continuously adjusted: f dgs Vibration frequency of the vibration generator 25 al dgs Load of the stabilization unit 23 on the left rail 14 ar dgs Load of the stabilization unit 23 on the right rail 14 ag dgs Total load V dgs Overrun speed (forward speed) of the stabilization unit 23

[0047] The track position data recorded in working direction 7 upstream of the stabilization unit 23 are assigned to the current work station 22. This means that before the stabilization process, all track position data are recorded with a spatial assignment to track 4. For example, the track position data is supplemented with position data from a navigation satellite system (GNSS data). With known distances between the measuring points 10 and the work station 22, a simple reference can be established over a recorded distance.

[0048] Specifically, the following measurement data are recorded in advance and then used to adjust the operating parameters if the respective measuring point 10 corresponds to the current work point 22: h ivs Actual longitudinal height of the untreated track 4 q ivs Actual transverse slope (actual superelevation) of the untreated track 4 h ins Actual longitudinal height of the tamped track 4 q ins Actual transverse slope (actual superelevation) of the tamped track 4

[0049] In addition, specified values ​​for a final target track position are used to adjust the operating parameters: hs Target longitudinal height of the finished track 4 qs Target transverse inclination (target superelevation) of the finished track 4

[0050] Example formulas for the ongoing adjustment of operating parameters use the following weighting factors: g f1 1st weighting factor for vibration frequency g f2 2nd weighting factor for vibration frequency g a1 1st weighting factor for load g a2 2nd weighting factor for load g a3 3rd weighting factor for load g a4 4th weighting factor for load g v1 1st weighting factor for overrun speed g v2 2nd weighting factor for overrun speed

[0051] At the start of a work assignment, the following initial values ​​are used for the operating parameters: f 0 Initial value for vibration frequency a 0 Initial value for the left and right load v 0 Initial value for the overrun speed

[0052] The following formulas are stored in the control device 12 in order to adapt the operating parameters of the dynamic track stabilizer 1 for the current work station 22 during a stabilization process: f dgs : = f 0 + g f 1 ⋅ h s − h ivs + g f 2 ⋅ h ins − h s al dgs : = a 0 + g a 1 ⋅ q s − q ivs + g a 2 ⋅ q ins − q s + g a 3 ⋅ h s − h ivs + g a 4 ⋅ h ins − h s ar dgs : = a 0 − g a 1 ⋅ q s − q ivs − g a 2 ⋅ q ins − q s + g a 3 ⋅ h s − h ivs + g a 4 ⋅ h ins − h s v dgs : = v 0 − g v 1 ⋅ h s − h ivs + g v 2 ⋅ h ins − h s ag dgs : = al dgs + ar dgs

[0053] Due to the effect of the dynamic track stabilizer 1, track 4 lowers during the crossing and changes its longitudinal height and / or cant. These changes are recorded by remeasuring the track geometry. The following track geometry data is used to adjust the track geometry correction and the operating parameters: h ind Actual longitudinal height of the stabilized track 4 q ind Actual transverse inclination (actual superelevation) of the stabilized track 4

[0054] For example, an iterative adjustment of the operating parameters was carried out using the following formulas stored in the control device 12: Δh : = h s − h ind Δq : = q s − q ind g f 1 n + 1 : = g f 1 n + k gf 1 ⋅ Δh g f 2 n + 1 : = g f 2 n + k gf 2 ⋅ Δh g a 1 n + 1 : = g a 1 n + k ga 1 ⋅ Δq g a 2 n + 1 : = g a 2 n + k ga 2 ⋅ Δq g a 3 n + 1 : = g a 3 n + k ga 3 ⋅ Δh g a 4 n + 1 : = g a 4 n + k ga 4 ⋅ Δh g v 1 n + 1 : = g v 1 n + k gv 1 ⋅ Δh g v 2 n + 1 : = g v 1 n + k gv 2 ⋅ Δh

[0055] During iterative adjustment, the original values ​​of the weighting factors are replaced with new values. If both the roll angle and the longitudinal height correspond to the respective target values ​​after the stabilization process, the dynamic stabilizer 1 is perfectly adjusted and no adjustment of the weighting factors takes place.

[0056] The factors used, k gf1 , k gf2 , k ga1 , k ga2 , k ga3 , k ga4 , k gv1 , k gv2 , determine a control gain and are determined, for example, in tests or simulations. The same applies to the initial values ​​of the operating parameters f 0 , a 0 , v 0 and to the initial values ​​of the weighting factors g f1 (0), g f2 (0), g a1 (0), g a2 (0), g a3 (0), g a4 (0), g v1 (0), g v2 (0). By carrying out the procedure frequently, empirical values ​​are gained so that suitable values ​​are available at the start of a work operation.

[0057] In the extended procedure involving tamping machine 5, the following overlift values ​​(correction values) are specified: h ks : = h s − h ivs ⋅ F h q ks : = q s − q ivs ⋅ F q In a simple implementation, a fixed factor F h , F q is specified to determine the camber values. However, known methods for continuously adjusting the camber to changing track conditions can also be used.

Claims

1. A method for correcting vertical position defects of a track (4) after a lifting-tamping process, with a stabilizing process carried out by means of a dynamic track stabilizer (1) in which a stabilizing unit (23) acts on the track (4) at a forward-moving working point (22) in a working direction (7), with track position data of the untreated track (4) being recorded before the lifting-tamping process, and with track position data of the tamped track (4) being recorded after the lifting-tamping process at a measuring point (10) located in front of the stabilizing unit (23) in the working direction (7), characterized in that additional track position data of the stabilized, lowered track (4) are recorded outside the sphere of influence of the stabilizing unit (23) at a post-measuring point (21) located behind the stabilizing unit (23) in the working direction (7), and that the dynamic track stabilizer (1) is actuated during the stabilizing process as a function of track position data of the untreated and the tamped track (4) at the working point (22) and of track position data of the stabilized, lowered track (4) at the post-measuring point (21), that a track position measuring system (9) comprising a plurality of measuring devices (8) is carried along with the dynamic track stabilizer (1), and that the corresponding track position with respect to a common reference system is recorded at the respective measuring point (10, 21) by means of the assigned measuring devices (8).

2. A method according to claim 1, characterized in that track position data of a target position (20) of the track (4) are predefined, and that the dynamic track stabilizer (1) is additionally actuated during the stabilizing process as a function of correction data which are derived for the working point (22) from the data of the target position (20) and the track position data of the untreated track (4).

3. A method according to one of the claims 1 to 2, characterized in that a longitudinal gradient or longitudinal level and a crossfall or superelevation of the track (4) are each measured at the respective measuring point (10, 21) to record the track position data.

4. A method according to one of the claims 1 to 3, characterized in that at least one of the following operating parameters of the dynamic track stabilizer (1) is changed during the stabilizing process as a function of the recorded track position data: - a vibration frequency, - a travelling speed (vdgs), - an imposed load acting on a left rail (aldgs), - an imposed load acting on a right rail (ardgs), - a total imposed load.

5. A method according to claim 4, characterized in that the stabilizing process is started with an output value of the respective operating parameter, and that an adjusted value is continuously calculated for the respective operating parameter during the stabilizing process by means of an algorithm set up in a computing unit.

6. A method according to claim 5, characterized in that weighting factors are stored in the algorithm for the respective operating parameter, and that the weighting factors are continuously adjusted by means of a control.

7. A method according to one of the claims 1 to 6, characterized in that the reference system is formed by means of a camera (29) attached to one of the measuring devices (8) and a reference mark (30) attached to another measuring device (8) and positioned in a recording area (32) of the camera (29), and that measuring marks (30) attached to the remaining measuring devices (8) are recorded by means of the camera (29) in order to record the track position data.

8. A system for carrying out a method according to one of the claims 1 to 7, having a track position measuring system (9) and having a dynamic track stabilizer (1) comprising a stabilizing unit (23) for correcting vertical position defects at a forward-moving working point (22) of a track (4), characterized in that the track position measuring system (9) is set up to record the track position at a measuring point (10) arranged in front of the dynamic track stabilizer (1) in the working direction (7) and at a post-measuring point (21) arranged after the dynamic track stabilizer (1) in the working direction (7) outside the sphere of influence of the stabilizing unit (23), that the dynamic track stabilizer (1) comprises a control device (12) to which track position data recorded by means of the track position measuring system (9) are fed, and that the control device (12) is set up to actuate the dynamic track stabilizer (1) as a function of track position data assigned to the working point (22) and of track position data of the stabilized, lowered track assigned to the post-measuring point (21) outside the sphere of influence of the stabilizing unit (23).

9. A system according to claim 8, characterized in that a distance (a) between the working point (22) and the post-measuring point (21) lies in a range between 3 m and 10 m, particularly between 5 m and 8 m.

10. A system according to claim 8 or 9, characterized in that the control device (12) comprises a computing unit in which an algorithm is implemented for recalculating at least one operating parameter of the dynamic track stabilizer (1) on the basis of continuously updated track position data.

11. A system according to one of the claims 8 to 10, characterized in that a stabilizing unit (23) comprises a vibration generator (25) and roller clamps (24) that can be clamped onto rails (14) of the track (4) and is supported against a machine frame (2) with imposed load drives (26) that can be actuated separately.

12. A system according to one of the claims 8 to 11, characterized in that a tamping machine (5) is arranged immediately in front of the track stabilizer (1) in the working direction (7), and that the track position measuring system (9) comprises at least one measuring device (8) which is assigned to the tamping machine (5).

13. A system according to one of the claims 8 to 12, characterized in that a camera (29) is attached to a first measuring device (8), that a reference mark (30) is attached to a second measuring device (8), and that at least one further measuring device (8) with a measuring mark (30) is attached between the first and second measuring device (8).

14. A system according to claim 13, characterized in that the track position measuring system (29) comprises a flash lamp (33) that can be actuated together with the camera (29).