Method for detecting a vertical track level

Abstract

The invention relates to a track recording vehicle (1) for detecting the resilience of a rail track (5), comprising: a machine frame (2), which can be moved on the rail track (5) supported on two rail-mounted travel units (3); a first measuring system (7) for detecting a vertical distance of the rail track (5) under load and a second measuring system (13) for detecting a vertical distance of the rail track (5) under no load. The first measuring system is coupled to an analytical device (11) for calculating the curve of a first vertical arrow height (12) and the second measuring system (13) is designed to determine a curve of a second vertical arrow height (14) and comprises a common reference base, two outer measuring points (15, 16) under load and an interposed medium measuring point (17) without or with reduced load, and the analytical device (11) is designed to calculate subsidence (19) of the rail track (5) under load from the two arrow heights (12, 14). A track recording vehicle (1) of the above type detects subsidence of the rail track (5) under load in a single measuring run.

Description

field of technology

[0001] The invention relates to a method for measuring a track at two outer measuring points under load and at a middle measuring point in between without load by means of a track measuring vehicle with a machine frame which is movable on the track supported on two rail bogies, with a first measuring system for detecting a vertical distance of the track under load and with a second measuring system for detecting a vertical distance of the track in the absence of a load, wherein the first measuring system is coupled to an evaluation device and wherein both measuring systems have a common reference base. State of the art

[0002] Track maintenance is based on geometric parameters. One of these parameters is the vertical track position under load. Typically, the load used is the weight of a track measuring vehicle, which travels along the track and records the vertical track position.

[0003] Another parameter used to assess track condition is track compliance. To determine this, the track position must also be measured without load and compared with the track position under load. This is usually done through two separate measurements.

[0004] DE 102 20 175 C1 discloses a method and a track measuring vehicle with which the compliance of the track can be measured in a single measurement pass. For this purpose, two measuring systems are installed on the track measuring vehicle. A first measuring system records the relative track position under load with respect to a fixed inertial reference system. A measuring head, measuring vertically using optical triangulation, is guided laterally along the rail.

[0005] A second measuring system records the track position without load relative to the same reference system using another vertical measuring head mounted on a system carrier. Lateral rail tracking is also required for the second measuring system. Furthermore, movements of the track measuring vehicle must be compensated for using compensation devices and roll angle compensators. Furthermore, complex calibration devices with cameras and light sources are required to align the two measuring systems. Summary of the invention

[0006] The invention is based on the object of specifying a generic track measuring vehicle and a method with which the compliance of the track can be determined in a simple manner.

[0007] According to the invention, this object is achieved by the features of claim 1. Advantageous developments of the invention emerge from the dependent claims.

[0008] The first measuring system records the course of a first vertical arrow height under load using the well-known inertial measurement principle or by measuring a vertical axis acceleration. Initially, a true-to-form measurement signal is determined. Subsequently, a three-point signal is calculated for a virtual bowstring using an evaluation device, which corresponds to the course of the vertical arrow height using the traveling-vision measurement principle (three-point measurement).

[0009] The second measuring system is designed to determine the course of a second vertical sweep, with a common reference base, two outer measuring points under load and an intermediate measuring point with or without a reduced load. The evaluation device is configured to calculate the track deflection under load from the two sweeps. The unloaded section of the track between the two track carriages is included in the measurement of the second sweep. This allows the deflection under load to be easily determined together with the first sweep.

[0010] Such a track measuring vehicle measures the track's compliance under load in a single measurement run, requiring only the determination of the two vertical sweeps. Motion compensation devices or adjustment devices to align the two measuring systems are not required. Thus, track subsidence can be determined simply and efficiently with just a few system components.

[0011] A further development, not claimed, provides for the first measuring system to be designed as an inertial measuring system and to comprise a measuring frame mounted on one of the rail bogies. In this way, a measuring system already present on modern track measuring vehicles is used to determine the course of the first vertical sweep of the track under load.

[0012] It is advantageous if an inertial measurement unit and at least two position measuring devices for determining the position of the measuring frame relative to the track rails are arranged on the measuring frame. This provides an accurate profile of both rails. To be able to record such a profile regardless of the speed of the track measuring vehicle, two spaced-apart position measuring devices are provided per rail.

[0013] In a non-stressed variant, the second measuring system comprises two outer measuring carriages for recording the track position at the outer measuring points and a middle measuring carriage for recording the track position at the intermediate measuring point. This provides a robust structure that allows direct recording of the second vertical sweep height.

[0014] Advantageously, at least one measuring chord is stretched between the two outer measuring carriages as a reference base. For example, the distance of a steel chord stretched in the middle to a measuring device on the middle measuring carriage can be easily measured as a second vertical vertex. With a measuring chord above each rail, a vertical vertex can be determined for each rail.

[0015] With only one centrally tensioned measuring chord, it is advantageous if each measuring carriage is equipped with a cant measuring device to determine a separate second vertical vertex for each rail. This is also advantageous if the machine frame is used as the reference base. This continuously measures the distance between the measuring carriages and the machine frame.

[0016] Another variant, not yet claimed, provides for the second measuring system to comprise non-contact distance measuring devices, which are arranged on the machine frame above the three measuring points and measure the respective distance to a rail of the track. In this case, the measuring carriages are eliminated, and the machine frame serves as a common reference base. A particularly rigid machine frame is provided to prevent disruptive vibration influences.

[0017] The method according to the invention for measuring a track using the described track measuring vehicle provides that the first vertical sag and the second vertical sag are determined with a matching chord length and chord pitch, and that the two vertical sags are subtracted to calculate the track deflection under load. In this way, the deflection under load can be determined with minimal computational effort.

[0018] In a simple version of the method, the first vertical sag and the second vertical sag are each determined at the center of the track, whereby an average track depression is calculated. Such a determination of the depression is sufficient in many applications.

[0019] For a more precise analysis of the track condition, it is advantageous if the first vertical arrow height and the second vertical arrow height are determined separately for both rails of the track and if a separate depression profile is calculated for each rail. Short description of the drawings

[0020] The invention is explained below by way of example with reference to the accompanying figures. They show schematically: Fig. 1Track measuring vehicle in an oblique view Fig. 2Diagrams of the vertical track position Fig. 3Determination of the second arrow height using measuring trolleys at a first track position Fig. 4Determination of the second arrow height using measuring trolleys at a second track position Fig. 5Determination of the second arrow height using distance measuring devices Description of the embodiments

[0021] Fig. 1 shows a track measuring vehicle 1 with a machine frame 2, which is supported on two rail bogies 3 and can be moved along two rails 4 of a track 5. The rail bogies 3 are designed as bogies. A car body 6 is mounted on the machine frame 2, containing driver or operator cabins, drive components, and various control and measuring devices.

[0022] A first measuring system 7 is arranged on one of the rail carriages 3. In Fig. 1This is a so-called inertial measurement system. Alternatively, another measurement system can be used that records the vertical course of track 5 under load (e.g., measuring the axle bearing acceleration).

[0023] The first measuring system 7 comprises a measuring frame 8, which is connected to the axle bearings of the rail bogie 3 and precisely tracks the vertical track position. An inertial measuring unit 9 is connected to the measuring frame 8. This unit measures every movement relative to a stationary reference system and provides a spatial curve in the center of the track and / or two spatial curves of the inner rail edges.

[0024] To computationally compensate for lateral relative movements of the rail bogie 3 relative to the track 5, position measuring devices 10 (Optical Gauge Measuring System) are arranged at four points on the measuring frame 8. These continuously measure the distances to the inner edges of the rails 4, although at a minimum measuring speed, two position measuring devices 10 are sufficient. This allows the track position in the transverse direction to be precisely measured.

[0025] Measurement data acquired by the first measuring system 7 are available in an evaluation device 11 for calculating the course of a first vertical sag 12 of the track position under load. The results of a second measuring system 13 are also fed to the evaluation device 11. This system is intended to determine the course of a second vertical sag 14.

[0026] The vertical height of the arrow 12, 14 is known to be the vertical distance of a track position or rail line from a bowstring. The so-called "wandering vision" measurement principle (three-point measurement) is used, with a virtual measuring chord being used as a reference base to calculate the first vertical height of the arrow 12.

[0027] The second measuring system 13 measures the track position in the longitudinal direction at two outer measuring points 15, 16 under load and at a central measuring point 17 located between them, without or with reduced load. The measurements are taken with respect to a common reference base according to the determination of the first vertical sag 12.

[0028] The second measuring system 13 comprises, for example, a central measuring carriage 18 suspended from the machine frame 2, which is arranged between the two rail bogies 3 in an unloaded section of the track 5. The central measuring carriage 18 is lightweight, so this can be disregarded. It is also possible to provide a weight-compensating suspension for the central measuring carriage 18, which merely prevents it from lifting off the rails 4.

[0029] At the two outer measuring points 15, 16, track 5 is subjected to an approximately equal load. This is achieved by evenly distributing the weight of the machine frame 2, including the car body 6 and various devices, between the two rail bogies 3. This results in a characteristic depression 19 under load for a particular point on track 5, regardless of which rail bogie 3 applies the load.

[0030] Fig. 2 shows diagrams with different vertical track positions 20, 21, and 22, with the x-axis representing a track path and the y-axis representing a vertical deviation from a perfectly level track position. A thin solid line corresponds to an unloaded track position 20, and a dashed line corresponds to a track position 21 under load. A thick solid line shows the actual track position 22 during travel by the track measuring vehicle 1. For clarity, the deviations from a level track position are greatly exaggerated.

[0031] In the upper diagram, track 5 is not yet in use, which is why the unloaded track position 20 corresponds to the actual track position 22. The three diagrams below show a chronological sequence of travel on track 5. The loads on track 5 from the rail bogies 3 are represented by equal point loads 23. This assumption is also used to calculate the course of the first arrow height 12 using the evaluation device 11.

[0032] The Figures 3 to 5 show the geometric relationships in detail, whereby in the Figures 3 and 4Three measuring carriages 18, 24, 25 are provided as components of the second measuring system 13. In addition to the middle measuring carriage 18, there are two outer measuring carriages 24, 25, which are arranged in the immediate vicinity of the rail bogies 3 and thus in loaded sections of the track 5. Arranging the outer measuring carriages 24, 25 between the axles of a rail bogie 3 designed as a bogie also represents a useful variant.

[0033] A measuring chord 26 is stretched between the two outer measuring carriages 24, 25. Alternatively, the machine frame 2 can serve as a common reference base, in which case it is designed to be correspondingly rigid. Distance measuring devices are also required to record the distances between the machine frame 2 and the individual measuring carriages 18, 24, 25.

[0034] In the example shown, a symmetrical chord pitch is used. The middle measuring carriage 18 is therefore at an equal distance 27 from the two outer measuring carriages 24, 25. However, an asymmetric chord pitch is also possible. It is important to ensure that the middle measuring carriage 18 is at a sufficient distance from the two outer measuring carriages 24, 25 to prevent the loaded track sections from influencing the middle measuring carriage 18.

[0035] While the track measuring vehicle 1 travels along track 5, the second vertical vertex 14 is continuously measured using this second measuring system 13. Specifically, this is the vertical deviation of the center measuring carriage 18 from the measuring chord 26 compared to a completely level track layout. In a simple embodiment, the vertex measurement is performed in the center of the track. However, the vertical vertexes of the respective rails 4 can also be measured. In this case, either a separate measuring chord 26 is stretched over each rail 4, or each measuring carriage 18, 24, 25 includes a cant measuring device (inclinometer) to determine the longitudinal heights of the rails 4 from a height in the center of the track.

[0036] Using the evaluation device 11, the first vertical vertex 12 is calculated from the stored track position data of the first measuring system 7. A virtual reference base is used, which provides corresponding results to the second measuring system 13. For example, this is a virtual measuring chord 28, which connects the outer measuring points 15, 16 and thus runs parallel to the measuring chord 26 of the second measuring system 13.

[0037] The first vertical sag 12 thus results from the calculated vertical distance between the virtual measuring chord 28 and the track position point 29, which was recorded during the measurement run using the first measuring system 7 at the central measuring point 17. The depression 19 under load at the central measuring point 17 is thus the difference between the first and second vertical sags 12, 14, with the sags 12, 14 being signed.

[0038] In Fig. 3a situation is shown in which the virtual measuring chord 28 runs at the middle measuring point 17 between the unloaded and loaded track 5. Then the two vertex heights 12, 14 have different signs and the subtraction leads to a summation of the absolute values ​​of both vertex heights 12, 14. The situation is different in Fig. 4 , where both sags 12, 14 indicate an upwardly curved track position. This situation is typical, because the vertical sags 12, 14 of a track section are usually significantly greater than a depression 19 under load.

[0039] Fig. 5shows a second measuring system 13 without measuring carriages 18, 24, 25. The machine frame 2 serves as a common reference base for the three-point measurement. A non-contact distance measuring device 30 is arranged above each of the three measuring points 15, 16, 17. This measures a respective distance 31, 32, 33 between a rail top edge and the machine frame 2 at the three measuring points 15, 16, 17.

[0040] In a simple embodiment, only the distances 31, 32, 33 to one rail 4 are determined. However, to determine a depression 19 of both rails 4 or in the center of the track, distance measurements must be performed for both rails 4. From the measured distances 31, 32, 33, the second vertical arrow height 14 at the middle measuring point 17 can be easily calculated using the evaluation device 11. Specifically, the difference between the middle distance 33 and an average value of the two outer distances 31, 32 is determined. By filtering the output signals of the distance measuring devices 30, disruptive vibrations of the machine frame 2 can also be eliminated.

[0041] The calculation of the first vertical arrow height 12 is carried out as Fig. 3 described from the stored measured values ​​of the first measuring system 7 with respect to a virtual measuring line 28.

[0042] For most applications, it is negligible if the two outer measuring points 15, 16 are not located exactly at the points of greatest depression for determining the second sweep height 14. This is the case if the outer measuring carriages 24, 25 are arranged in front of or behind the loaded rail bogies 3. In any case, hollow positions in the track 5 can be reliably detected.

[0043] In order to be able to precisely determine the subsidence of track 5 in a further development of the invention, calculation parameters for track 5 (e.g., bedding ratio or bedding modulus) are stored in a memory of the evaluation device 11. Based on the measured compliance or a bending line of track 5, the maximum subsidence below the rail bogies 3 is then calculated using the known Zimmermann method.

Claims

1. A method of surveying a track (5) on two outer measuring points (15, 16) under load and on a central measuring point (17), lying there between, without load by means of a track measuring vehicle (1) with a machine frame (2) which, supported on two on-track undercarriages (3), is mobile on the track (5), with a first measuring system (7) for recording a vertical distance of the track (5) under load and with a second measuring system (13) for recording a vertical distance of the track (5) in the absence of load wherein the first measuring system is coupled to an evaluation device (11) and wherein both measuring systems have a common reference base, characterized in that by means of the evaluation device (11) a course of a first vertical versine (12) is computed and that by means of the second measuring system (13) a course of a second vertical versine (14) is determined, that the first vertical versine (12) and the second vertical versine (14) are determined with a coinciding chord length and chord division, and that the two vertical versines (12, 14) are subtracted for computing the subsidence (19) of the track (5) under load.

2. A method according to claim 1, characterized in that the first vertical versine (12) and the second vertical versine (14) are determined in the track center in each case, and that by this a median course of subsidence of the track (5) is computed.

3. A method according to claim 1 or 2, characterized in that the first vertical versine (12) and the second vertical versine (14) are determined separately for both rails (4) of the track (5), and that thus a course of subsidence is computed for each rail (4).

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