Method and track maintenance machine for correction of track position errors

Abstract

A method for the correction of vertical position error of a track by a track tamping machine and a dynamic track stabilizer. Starting from a registered actual position, an over-lift value is prescribed for a treated track location with which the track is lifted into a preliminary over-lift track position and tamped. The track is subsequently lowered by dynamic stabilization into a resulting final track position. In this, a smoothed actual position course is formed from a course of the actual track position, wherein an over-lift value is prescribed for the treated track location in dependence of the course of the actual track position with regard to the smoothed actual position course. In this way, only short-wave track faults are treated with an over-lift value.

Claims

1. A method of correcting vertical position faults of a track, the method comprising: measuring an actual track position; forming a smoothed actual position course from a course of the actual track position; starting from the actual track position, prescribing an over-lift value for a given track location that is being treated, the over-lift value being dependent on the course of the actual track position relative to the smoothed actual position course; lifting the track into a preliminary over-lift track position defined by the over-lift value of the given track location and tamping the track with a track tamping machine; and subsequently lowering the track by dynamic stabilization with a dynamic track stabilizer into a resulting final track position.

2. The method according to claim 1, which comprises, subsequent to the dynamic stabilization, detecting residual fault values with a re-measuring system, and prescribing the over-lift value for a currently treated track location in dependence of at least one residual fault value.

3. The method according to claim 1, which comprises determining the smoothed actual position course from the course of the actual track position by way of a low-pass filter.

4. The method according to claim 1, which comprises determining local maxima of the course of the actual track position by way of the smoothed actual position course.

5. The method according to claim 4, which comprises forming a polygon which connects local maxima of the stored course of the actual track position.

6. The method according to claim 1, which comprises determining a wavelength for the vertical position faults from the course of the actual track position, and prescribing the overlift value also in dependence on the wavelength.

7. The method according to claim 1, determining a deviation value for the given track location from the course of the actual track position with regard to the smoothed actual position course and forming the overlift value by multiplying the deviation value by an overlift factor.

8. The method according to claim 7, which comprises iteratively adapting the overlift factor while taking into account a residual fault value of the track detected after the dynamic stabilization has taken place.

9. The method according to claim 8, which comprises detecting the residual fault value is detected at a track location with a local minimum of the course of the original actual track position.

10. The method according to claim 9, which comprises adding the residual fault value detected at a track location and the overlift value applied at the track location to form a sum value, and, for prescribing a new overlift factor, dividing the deviation value originally present at this track location by the sum value.

11. The method according to claim 10, which comprises using several residual fault values detected one after another for determining the new overlift factor.

12. A track maintenance machine for correction of vertical position errors of a track, the track maintenance machine comprising: a track tamping machine for lifting and tamping the track; and a dynamic track stabilizer for dynamically stabilizing the track; and an evaluation device and a control device configured for executing the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described by way of example below with reference to the attached figures. There is shown in schematic representation in:

(2) FIG. 1 a track tamping machine with a dynamic track stabilizer

(3) FIG. 2 a diagram of the track position according to the prior art

(4) FIG. 3 a diagram of the track position according to the present invention

(5) FIG. 4 a diagram with a polygon

DESCRIPTION OF THE EMBODIMENTS

(6) The track maintenance machine 1 shown in FIG. 1 is intended for a correction of vertical position errors of a track 2 resting in the ballast bed 3. In this, a track tamping machine 5 situated at the front in the working direction 4 is coupled to a dynamic track stabilizer 6.

(7) The track tamping machine 5 comprises a tamping unit 7 for tamping sleepers 8, and a track lifting unit 9 located in front. Both units 7, 9 are arranged on a common satellite frame 10. At a front end, the latter is mounted for longitudinal displacement in a machine frame and supported at a rear end on a separate rail undercarriage 11.

(8) Arranged above the same is a work cabin 12 with a control device 13. For the correction of vertical position errors of the track 2, a reference system 15 having measuring axles 14 is provided. With this, the course of the actual track position I is determined. Alternatively, a measuring run by means of a separate measuring car can take place, with subsequent transmission of the measurement data to the machine 1.

(9) The dynamic track stabilizer 6 comprises stabilizing units 16 which can be pressed upon the track 2 with a vertical load and simultaneously set the track in transverse vibrations. For check measurement of the resulting final track position R, a separate re-measuring system 17 with measuring axles 18 is provided.

(10) Shown in FIG. 2 are the track position courses which change during tamping and stabilizing within the scope of the known “Design Overlift”. In this, the extension of the track 2 in the working direction 4 is indicated in the x-axis, and the respective vertical position of the track 2 is indicated in the y-axis. For example, in the case of a level track section, a target track position S extends in the x-axis, with a vertical deviation equalling zero.

(11) With regard to the target track position S, the detected actual track position I has vertical error values f of varying magnitude. Up to now, it has been customary for tamping a track 2 to prescribe an overlift value u correlating to the respective error value f. Set as a specific lifting value h was the error value f plus the correlating overlift value. The result was a temporary overlift track position U. By means of the dynamic track stabilizer 6, a lowering into a final track position R took place subsequently.

(12) With the method according to the invention, first a smoothed actual position course G of the track 2 is formed. In FIG. 3, the track position courses I, S, R, U according to FIG. 2 are also shown. By means of a low-pass filter, the smoothed actual position course G is determined from the course of the actual track position I. A variant provides that a sliding mean value is determined as smoothed actual position course G via a pre-set averaging length (for example, 30 m).

(13) All of the upper turnaround points of the course of the actual track position I which lie above the smoothed actual position course G are recognized as local maximums 19. With this point cloud, it is possible to determine a curve function by means of which a curve G′ connecting the local maximums 19 can be described. Alternatively, the smoothed actual position course G can be shifted in the direction of the local maximums 19, so that the displaced curve G′ approximately connects the local maximums 19.

(14) In a further method step, deviation values a are determined as difference values between the course of the actual track position I and the curve G′ connecting the maximums 19. With an overlift factor c, this results in the overlift values u by multiplication:
u=c.Math.a

(15) Consequently, there are no overlift values at the track locations with deviation values a equalling zero (local maximums of the course of the actual track position I). Here, the track is lifted with a basic lifting value b which is required for attaining the target track position S. In this, the error value f known from the survey of the track 2 is added to a sinking value d occurring during stabilizing:
b=f+d

(16) For the other track locations, an overlift value u according to the above-shown formula ensues. In this, the greatest overlift values u occur at track locations with a local minimum 20 in the course of the actual track position I. In total, a lifting value h thus results as the sum of the basic lifting value b and the overlift value u:
h=b+u

(17) A simplified determination of the deviation values a is shown in FIG. 4. In this, the maximums 19 of the course of the actual track position I are connected by a polygon P. The individual deviation values a ensue as the difference between the course of the actual track position I and the polygon P.

(18) The resulting final track position R after stabilizing has taken place can be used to optimize the overlift factor c. Only at the start of the method, an overlift factor c derived from empirical data is prescribed. Thereafter, an iterative adaptation takes place.

(19) As can be seen in FIG. 4, the method uses residual error values r, measured at local minimums 20 of the course of the actual track position I, which lie behind a currently treated track location i with respect to the working direction 4. In this, detection takes place by means of the re-measuring system 17. For computation of the overlift u.sub.(i) at the treated track location i, the overlift factor c.sub.(i) is prescribed as follows:
c.sub.(i)=a.sub.(i-1)/u.sub.(i-1)+r.sub.(i-1))

(20) If a positive residual error value r.sub.(i-1) remains, then the overlift factor c.sub.(i) is automatically reduced, and the following overlifting u.sub.(i) turns out smaller. However, if the track 2 sinks below the target track position S during stabilization, then the overlift value u.sub.(i) increases for the following treatment intervals.

(21) An ideal overlift factor c.sub.(i) is computed by mean value formation over several track position waves and prescribed to the track tamping machine 5 as a new overlift factor c.sub.(i). For example, the following formula with several residual error values r.sub.(i-1), r.sub.(1-2), r.sub.(1-3) is applied:
c.sub.(i)=((a.sub.(i-1)/(u.sub.(i-1)+r.sub.(i-1)))+(a.sub.(i-2)/(u.sub.(i-2)+r.sub.(i-2))+(a.sub.(i-3)/(u.sub.(i-3)+r.sub.(i-3)))/3

(22) The track maintenance machine 1 comprises an evaluation device 21 which is designed for the above-explained calculations. This is, for example, an industrial computer. The values of the actual track position I and of the resulting final track position R are fed to the evaluation device 21 in order to determine from this in real time the overlift value u.sub.(i). In addition, currently calculated values c.sub.(i), u.sub.(i) can be shown to a machine operator by means of a display unit. In this, it is possible to emit a warning signal in the event of erratic changes of the calculated overlift factor c.sub.(i).

(23) A further improvement for adapting the overlift factor u.sub.(i) can be achieved by inclusion of a detected wavelength of the vertical position errors. Normally, this is between 10 m and 12 m. In a track 2 with poor ballast condition, however, track position errors with a wavelength between 5 m and 6 m develop.

(24) The improved method provides that first the wavelength is determined from the actual track position, and then the overlift value u.sub.(i) is adjusted in dependence of the wavelength. In the case of a shorter wavelength, for example, the overlift factor c.sub.(i) is increased in order to counteract a likely re-sinking of the track 2 at track locations i with poor ballast condition.