Abstract
The invention relates to a method for the automatic correction of the position of individual faults (H(n)) of a track formed by rails (16) and sleepers (9) with a track tamping machine (2). After the left and right rails have been surveyed independently by means of an inertial measuring unit (11), the length and position of the individual fault (TAMP, S, E) to be corrected is determined by taking into account a limit value of the individual faults (F.sub.LIM) and a maximum extension (s.sub.max) in the longitudinal direction of the track (s). The tamping units (7) of the tamping machine (s) are positioned exactly at the starting point (S) and end the tamping at the end point (E) of the determined track correction section (TAMP). Both track sections (F.sub.LI,F.sub.RE) are tamped and corrected simultaneously.
Claims
1. A method for automatically correcting the position of a track formed by left and right rails and sleepers with a track tamping machine, said method comprising the following steps: surveying the left and right rails of a track section independently of each other so as to determine and record an actual height position of each rail, a track direction, and a track superelevation using an inertial measuring unit and a computing and control unit; determining a starting point and an end point of an individual fault of the left rail and of the right rail to be corrected based at least in part on a limit value of the individual fault and a maximum extension in a longitudinal direction of the track; selecting the starting point depending on progression of the individual fault of the rail that is closer to the track tamping machine and selecting the end point depending on progression of the individual fault of the rail that is farthest in the longitudinal direction from the track tamping machine; defining a height reference line for the left rail and a height reference line for the right rail based at least in part on the track superelevation; positioning tamping units of the tamping machine and starting tamping exactly at the starting point of the individual fault of the determined track correction section, wherein sections of both left and right rails are corrected simultaneously and, in addition to the individual fault, the track direction is also corrected, and wherein the tamping is terminated at the end point.
2. The method according to claim 1, wherein the method further comprises after the surveying, test tamping in a region of maximum faults occurring so as to determine ballast bed hardness and, on the basis of the ballast bed hardness, the track is overlifted so as to improve the durability of the track position correction by using an expected settlement in the track position correction.
3. The method according to claim 2, wherein depending on the ballast bed hardness determined by the test tamping and the lifting correction height, the track is controlled by the tamping machine in operating modes of single tamping, multiple tamping, automatic optimized tamping or high-pressure tamping.
4. The method according to claim 2, wherein, depending on the ballast bed hardness determined by the test tamping, worn and worn-out ballast is replaced using a ballast replacement machine and then a new surveying step is carried out with subsequent individual fault correction.
5. The method according to claim 1, wherein the starting point of the tamping is located at a range before an actual start of the individual fault and the end point is located at a range after an actual end of the individual fault.
6. The method according to claim 1, wherein lifting is built up away from the starting point via a ramp and is reduced towards the end via a ramp.
7. The method according to claim 1, wherein immediately after the individual fault correction the track is processed with a dynamic track stabilizer.
8. The method according to claim 1, wherein ballast bed hardness is determined at each tamping at each sleeper and is recorded and stored as proof of quality and used to predict durability of the individual fault correction.
9. The method according to claim 1, wherein a respective position of the tamping unit relative to the track is displayed on a monitor.
Description
BRIEF DESCRIPTION OF THE INVENTION
(1) The drawings describe the method according to the invention, wherein:
(2) FIG. 1 schematically shows an individual fault tamping machine;
(3) FIG. 2 schematically shows a measured individual fault of a rail line;
(4) FIG. 3 schematically shows a representation of the measured individual fault curves of the left and right rail;
(5) FIG. 4 shows a diagram showing the course of the settlement depending on the elevation, as well as the course of the remaining elevation in the track;
(6) FIG. 5 schematically shows an individual fault, the course of an overlift of the track and the resulting track position after stabilization of the track (after complete settlement);
(7) FIG. 6 schematically shows an individual fault and the course of the ballast bed hardness over the length of the individual fault.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(8) FIG. 1 shows an individual fault tamping machine 2. The working direction is indicated by W. A lifting and lining device 13 is used to lift and straighten the track to the target position by means of lifting drives 3 and lining drives 4. The track position is corrected by the tamping unit 7 and the tamping tools 8, 15 which plunge into the ballast and compact the ballast under the sleepers 9. The machine 2 is powered by a drive motor 5 during work and travel. The machine 2 is designed in such a way that it can also correct individual faults in switches. For this purpose, the machine is equipped with pivotable tamping tines 8, 15, split-head tamping units 7 and a rotating device 6 for the tamping units 7. The machine 2 can be moved along the track 16 by means of bogies 12. The rails 16 rest on the transverse sleepers 9 which lie in the ballast bed. The machine control and regulating system consists of the two measuring carriages 10 and the rear IMU measuring carriage 11. The machine control and measuring system is usually designed as a cord measuring system. In this case, one cord runs centrally for the lining position and two other cords are run over the rails 16 for the longitudinal height position. The sensors for recording the longitudinal heights and the direction are located on the center measuring carriage 10. The rear measuring carriage 11 is designed in such a way that an inertial unit or north-based navigation system mounted on it can record the longitudinal height of both rails, the directional position and the transverse height as a function of the path. An odometer is used to record the displacement s during the measurement run. The measured values are recorded, displayed and stored equidistantly on an on-board computer with display 18. The vehicle has two cabs 17.
(9) FIG. 2 shows an example of an individual fault curve F.sub.Li of the left rail along the curve length s of the track. F.sub.Lim indicates a limit below which a fault must fall in order to be treated as an individual fault to be corrected. A simple mathematical way to determine the size of the individual faults and the high points is to find the maxima (MAX) and minima (MIN). The typical length of a pronounced individual fault L.sub.Typ is between 12-15 m. If there are other individual faults in the neighborhood of the first detected fault that fall below the F.sub.Lim limit (MIN.sub.1, MIN.sub.2, MIN.sub.3), then these are only considered if they are within a maximum length s.sub.max (e.g. typically 35-40 m). This is to avoid that instead of correcting the dangerous individual faults, entire sections of the line are worked through. According to the invention, the aim is the automatic computer-aided determination of the defective tamping area and the tamping parameters. Mechanized correction of individual faults is only carried out in the case of dangerous individual faults which, if not corrected, would lead to a track blockage or a slow speed section. Since these should be corrected as quickly as possible, working through longer sections would be inefficient. F.sub.Lim is set in such a way that individual faults that are almost of the same magnitude as the actual triggering individual fault are also corrected. This is efficient because otherwise these faults would develop into a critical fault in the near future. H(n) indicates the lifting value at sleeper n. The dashed line connecting the maxima (MAX.sub.1, MAX.sub.2, MAX.sub.3) is the reference height line of the left rail to which the rail is brought by the correction. In order to achieve a uniform vertical stiffness profile in the longitudinal direction (softening the hard high point regions), tamping is started N sleepers (typically 6) before the high point MAX.sub.1 and ended M sleepers (typically 6) after the last high point MAX.sub.3. Since the track fault with the minimum MIN.sub.4 is above the fault limit F.sub.Lim (i.e. smaller) it is not considered for correction and remains uncorrected in the track. S marks the starting point of the tamping and E the end. The machine operator can determine the exact positioning at the starting point S using the graphic display on the master computer 18.
(10) FIG. 3 shows an example of the individual fault curve F.sub.Li of the left rail at the top and the individual fault curve F.sub.Re of the right rail at the bottom. The right rail shows an increasing superelevation u(x) as a general case. The individual fault is therefore in a transition arc. As described before, the individual faults with respect to start and end point are first treated separately for both rails. For the left rail, the reference line REF.sub.Li is obtained and for the right superelevated rail the reference line REF.sub.Re, which rises according to the superelevation ramp u(s). Since a settlement of 5 mm occurs after tamping even without lifting, the individual faults on the left and right are lifted separately in height, but both sides are always tamped under at the same time. The settlement then occurs equally on both sides of the rail, so that there is no twisting error. The first longitudinal height error detected in the longitudinal direction and to be corrected is taken as the starting point S, and the last longitudinal height error detected and to be corrected is taken as the end point E. In order to check whether any impermissible twisting errors occur, the difference of the superelevations is calculated over the typical base length B of the twist of 3 m.
(11) The twist V is calculated as: V=[u(n)+h(n)]?[u(n+B)+h(n+B)] where n is the sleeper under consideration. The twist is calculated for all positions starting at the starting point (or B=3 m before) to the end point (or B=3 m after) and compliance with the acceptance threshold for the twist is checked. If this is not complied with, then the reference elevation lines must be modified accordingly. This is necessary, as shown in the next figures, especially if the track is superelevated for reasons of higher durability of the track position, so that it adapts to the optimum straight reference line after the expected settlement during the stabilization phase of the track.
(12) FIG. 4 shows schematically the settlement S (line marked with triangles) depending on the previously performed uplift H. From this, the curve of the remaining uplift v in the track (permanent correction) can be indicated (line with dots). Such progressions are given in various publications. One of them can be found in Handbuch Gleis Author: Dr. Bernhard Lichtberger, DVV Media Group GmbH/Eurailpress (ISBN 978-3-7771-0400-3), 3.sup.rd edition from 2010 in FIG. 287 on page 463.
(13) The settlement S can be simplified depending on the uplift H as follows:
(14)
(15)
(16) For the remaining uplift H depending on the track fault F, the following applies:
(17)
(18) As can be seen from the formulas and the diagram, the track settles by S=5 mm at zero H=0 uplift. The reason for this is that the tamping tools 8, 15 take up space and displace part of the ballast just by dipping the tines into the ballast. This corresponds to a loosening of the ballast in the area of the sleepers, which then begin to settle under the live load.
(19) FIG. 5 shows the curve of an individual fault g (line with dots) as an example. In order to make the track position more durable, or to take into account the expected settlement, the above formula
(20)
is used to calculate the necessary uplift H (line with circles). The reference line for the height of the rail is now not a straight line running between the maxima but a curved line (line with diamonds). Under the tensile load, the track settles and assumes the reference height line (line with triangles) after complete stabilization. At the initial and final areas R, the lifting value H is built up via a ramp (length typically e.g. 3 m). Since the lifting values are initially zero or very small, the track settles below the zero reference line. This corresponds to a small residual longitudinal height error at the beginning and at the end which cannot be avoided, but can be neglected in practice. The overlift ?, the settlement s and the track position I after stabilization are shown.
(21) FIG. 6 shows as an example the curve of the individual fault e from the previous diagram (line with circles). The diagram shows the ballast bed hardness b determined by the fully hydraulic tamping unit during tamping. The ballast bed hardness in the marked area W is low. The cause is crushed rounded ballast that can no longer be sufficiently compacted (interlocked). If ballast is not replaced prior to reworking, this area should definitely be overlifted to ensure longer durability of the track. In the area N of the track fault, on the other hand, good normal ballast hardnesses are present. Durable tamping can be expected here. With the aid of the ballast hardnesses determined during tamping, the expected durability of the individual fault correction can thus be specified. In the example shown, the infrastructure manager should replace the ballast in the marked area of sleeper W with new serviceable ballast. After the measurement run, the ballast hardness or the achievable compaction force can be measured by test tamping (at least one in the areas of greatest uplifts, i.e. in the example at sleeper 17 and at sleeper 32). For this purpose, the test sleeper is tamped without uplift and the ballast bed hardness and the compaction force as well as the adjusting distance (moving distance of the tamping tines 8, 15) are determined. On the basis of the known conditions, the track can be overlifted. If a machine is on site with which ballast can be replaced in advance, this is carried out before tamping. After the ballast has been exchanged, a new measurement run must be carried out to plan the individual fault correction. After the work through, the track position can be artificially stabilized (settlement) by means of a dynamic track stabilizer. Stabilization with the dynamic track stabilizer reduces and smooths out some of the overlifted values caused by the track stabilizer. These settlements would take place without the use of the track stabilizer by the loading trains (the track stabilizer effect corresponds to approx. 150,000 Lto of equivalent train traffic).
DESIGNATIONS USED
(22) 1 Tamping unit 2 Tamping machine 3 Lifting cylinder 4 Lining cylinder 5 Diesel engine 6 Rotating device of tamping unit 7 Tamping tool 8 Tamping tine 9 Sleeper 10 Center measuring carriage 11 IMU measuring carriage 12 Bogie 13 Lifting and lining unit 14 Work cabin 15 Tamping tine 16 Rail 17 Driver's cabin 18 Master computer W Soft ballast bed, working direction of the machine N Normal ballast bed R Start and end ramp B Base length of twist S Starting point E End point MIN Minima in the height position MAX Maxima in the height position s Arc length M Re-tamping length N Pre-tamping length H(n) Lifts u(n) Superelevation F.sub.lim Critical error limit value TAMP Tamping area REF Reference line for lifting S.sub.max Limit range of maximum individual fault length
