Method and device for determining the condition of a trackbed

Abstract

The invention relates to a method for determining the condition of a trackbed (2), in particular the quality condition of a ballast bed, the method comprising the steps: acquiring measurement signals from at least one strain sensor (21); determining the condition of the trackbed (2) on the basis of the measurement signals, wherein the measurement signals are acquired by means of at least one strain sensor (21) which is attached to a track rail (7) in order to detect rail strain. The invention also relates to a device (1) for carrying out such a method.

Description

[0001] Method and apparatus for determining the condition of a track bed

[0002] The content of the German patent application DE 102025 101 317.9 is incorporated herein by reference.

[0003] The invention relates to a method for determining the condition of a track bed, in particular the quality of a ballast bed. Furthermore, the invention relates to a device for determining the condition of the track bed, in particular the quality of a ballast bed.

[0004] From WO 2024 / 052306 A1, a method and a device for determining the condition of a track bed are known. A position sensor detects the vertical position of a track rail during a track tamping operation. As the degree of compaction increases, the lifting of the track rails as the tamping tools penetrate the ballast bed also increases. Based on the vertical position, the locally achieved degree of compaction can thus be determined during the track tamping operation. A disadvantage is that the degree of compaction can only be determined at the location where the tamping operation is currently being carried out.

[0005] The invention is based on the objective of creating an improved method for determining the condition of a track bed, which is particularly flexible in terms of time and location and provides particularly comprehensive and reliable information about the condition of the track bed. This objective is achieved by a method for determining the condition of a track bed with the features of claim 1. It has been recognized that a method for determining the condition of a track bed, in particular the quality of a ballast bed, in which measurement signals are acquired by means of at least one strain sensor, can determine the condition of the track bed particularly comprehensively, reliably, and precisely, as well as with particularly high temporal and spatial flexibility, if the measurement signals are acquired by means of at least one strain sensor that is attached to a track rail to detect rail strain.Because at least one strain sensor is mounted on the track rail, the measurement signals can be recorded independently of a measuring vehicle, and in particular, independently of a track tamping machine equipped with the measuring device. This enables continuous monitoring of the track bed's condition. A short-term and / or localized response to a defect is possible, especially with appropriate maintenance measures and / or traffic control measures, such as restricting and / or closing a defective section of track. The method thus ensures the operation of a rail transport system in a particularly safe and economical manner.

[0006] A further advantage is that the condition determined based on rail strain correlates particularly closely with the requirements placed on the track, especially the track bed, since the stability of the track rail is ultimately crucial for rail traffic. In contrast to previously known methods, the at least one strain sensor preferably remains permanently attached to the track rail, thus eliminating contact problems, particularly those caused by contamination, between the track rail and a reversibly installed measuring device.

[0007] The track bed is preferably a ballast bed. Alternatively, the track bed can be designed as a solid or ballastless track.

[0008] Determining the condition of the track bed based on the measurement signals is preferably automated, in particular by means of an evaluation unit, especially an electronic one. The evaluation unit can be connected to at least one, and in particular all, strain sensors for receiving the measurement signals. The evaluation unit can include a signal converter for converting the signals from the strain sensors, especially optical signals, into electrical, and in particular digital, signals.

[0009] Preferably, the evaluation unit comprises at least one electronic processor and / or a data storage device. The data storage device may include a computer program containing instructions that instruct a computer to execute the method.

[0010] The invention also relates to the computer program product and the data storage device containing the computer program product.

[0011] The evaluation unit can be permanently installed, particularly on the track. The evaluation unit can be connected to the at least one strain sensor via a wired signal connection. For communication, particularly wireless and / or wired communication, with a rail vehicle and / or a central computing unit, especially a control center of the rail transport system, the evaluation unit can have at least one additional communication connection, in particular a radio module and / or a wired data interface.

[0012] The evaluation unit may have a data interface, in particular a network interface, in particular a wired interface, in particular a USB interface, and / or a wireless interface, in particular a GPRS interface and / or a WiFi interface, and / or its own power supply, in particular an electrochemical energy storage device and / or a photovoltaic system and / or an energy harvesting device, and / or an electrical connection, in particular for supplying the electrical energy required for operation, and / or a protective housing and / or a data storage device, in particular for temporarily storing the measurement signals and / or the information on the integrity of the railway system and / or reference values ​​of the measurement signals, and / or for storing the computer program product.in particular for automatically executing the procedure for determining the condition of the track bed and / or for carrying out statistical procedure steps, in particular for calculating the average and / or for determining a standard deviation, and / or having a processor for processing the measurement signals, in particular with a clock frequency of at least 8 MHz, in particular at least 1 GHz and / or a maximum of 100 GHz.

[0013] The evaluation unit and / or a central processing unit can be configured to determine the condition of the track bed using a structural-mechanical and / or numerical model, in particular a FEM model (Finite Element Method) and / or DEM model (Discrete Element Method), and / or using analytical equations. These are preferably implemented in a computer program and / or stored in a data memory of the evaluation unit and / or the central processing unit.

[0014] To determine the condition of the track bed, the measurement signal from at least one strain sensor can be evaluated individually, particularly at a specific point in time and / or over time. A single value can provide information about the current state of the track bed. The time-based trend can reveal a continuous change in its condition.

[0015] In principle, the condition of the track bed can be impaired by hollow areas and / or an insufficient degree of compaction and / or contamination and / or insufficient ballast quality, in particular due to poor grain size distribution, especially too high a proportion of fines, and / or unsuitable shape and / or insufficient compactness, and / or insufficient damping properties.

[0016] Preferably, at least one of the aforementioned defects is identified based on the measurement signals, preferably quantified, and / or its nature is determined, in particular it is distinguished from other types of damage or the individual type of damage is identified.

[0017] Preferably, when determining the condition of the track, a distinction is made between permanent and temporary or sudden changes in strain, particularly those resulting from a corresponding temporary or sudden load on the track, especially the rails and / or the track bed. Permanent changes in strain can indicate a serious defect. For example, permanent changes in strain can result from the sinking of a track sleeper due to a hollow section. For determining the degree of soiling or compaction of the track bed, the non-permanent, temporary, or sudden changes in strain are decisive, as they correlate with the stiffness of the track bed.

[0018] A sudden load or change in strain is understood to mean that these increase and then quickly or immediately decrease again, especially to the original level before the increase, or vice versa.

[0019] According to one aspect, at least one strain sensor, and in particular all strain sensors, can be fiber optic strain sensors, especially fiber Bragg grating sensors. Such a strain sensor ensures particularly precise measurement results, is corrosion-resistant, and its measurement signals can be reliably transmitted over long distances, especially more than 100 m, and are particularly interference-free. Furthermore, several such strain sensors can be integrated into a single optical fiber. Alternatively or additionally, at least one of the strain sensors can be an electrical strain sensor, especially a strain gauge.

[0020] According to one aspect, the condition of the track bed can be determined based on the measurement signals from several strain sensors, in particular at least 20, in particular at least 50, in particular at least 100, in particular at least 250, in particular at least 500, in particular at least 1,000, in particular at least 2,000 and / or a maximum of 10,000, in particular a maximum of 5,000, in particular a maximum of 3,000, strain sensors, which are preferably arranged at intervals along the track rail. With a sufficiently large number of strain sensors, the condition of the track bed can be monitored over long sections of track with high spatial and / or temporal resolution, in particular continuously. Changes in condition can thus be addressed quickly and locally with a targeted maintenance measure.The procedure ensures a particularly economical and safe operation of the rail transport system.

[0021] The measurement signals from the multiple strain sensors are preferably acquired repeatedly or continuously, in particular at a measurement rate of at least 1 / week, in particular at least 1 / day, in particular at least 1 / hour, in particular at least 1 / minute, in particular at least 1 Hz, and / or a maximum of 1 kHz. Preferably, the material properties are determined at each acquisition step.

[0022] The condition of the track bed can be determined particularly favorably using a machine learning method, especially artificial intelligence. For this purpose, a corresponding algorithm can be stored on or executed by the evaluation unit and / or the central processing unit. Training data can be provided to train the algorithm, encompassing the measurement signals for actual defects as well as for a target condition. This allows for particularly efficient and reliable evaluation of the large data volumes, especially when dealing with a large number of strain sensors. The condition of the track bed can be determined particularly well using an unsupervised learning method, for example, to detect anomalies, especially defects, in the track bed's condition.

[0023] According to a further aspect, the multiple strain sensors can be components of a linear detection device, which preferably extends over a measuring section along the track rail with a length of at least 50 m, in particular at least 100 m, in particular at least 250 m, in particular at least 500 m, in particular at least 1 km, in particular at least 3 km, and / or a maximum of 20 km, in particular a maximum of 10 km, in particular a maximum of 5 km. The multiple strain sensors can, in particular exclusively, be designed in the form of fiber optic strain sensors.

[0024] The linear detection element can be designed as a single piece, particularly one that is not divisible without damage. The linear detection element can have at least one and / or a maximum of five, particularly a maximum of two, connections, or a single connection for connecting to the electronic evaluation unit. The at least one connection can be designed for transmitting optical and / or electrical signals. The at least one connection can be located at a free end and / or between the free ends of the linear detection element. A connection located between the ends can be designed as a bending coupler. At least one connection can be designed as a monitoring connection.

[0025] The length of the measuring section is preferably measured along the linear detection means and / or along the track rails and / or is determined by the distance between the first and the last strain sensor of the linear detection means.

[0026] The linear detection means preferably comprises at least two, in particular at least five, in particular at least 10, and / or a maximum of 50, in particular a maximum of 20 signal lines, in particular optical and / or electrical signal lines. The linear detection means can be designed as a measuring tape, in particular with signal lines arranged adjacent to each other, in particular side by side.

[0027] The multiple signal lines can be materially bonded together to form the detection means and / or arranged within the same covering material, in particular insulating sheath, and in particular glued together by this.

[0028] Preferably, the linear detection means is further developed with at least one of the features described in PCT / EP2024 / 070372, the contents of which are incorporated herein by reference.

[0029] Preferably, the linear detection means, in particular the multiple strain sensors, is designed to be attached to the at least one track rail, in particular to be clamped and / or glued to it, especially in the area of ​​the rail fastening or the track sleepers and / or on the rail foot and / or the rail web and / or the rail head, and / or to be laid below and / or on and / or within the track sleepers, in particular to be fastened. According to one aspect, the condition of the track bed can be determined on the basis of the measurement signals at at least 25, in particular at least 50, in particular at least 100, in particular at least 250, in particular at least 500, and / or a maximum of 5,000, in particular a maximum of 1,000, evaluation positions and / or strain sensors spaced apart from one another along the track rail.At an evaluation position, one or more strain sensors can be provided, in particular for determining rail strains in one or more directions and / or at one or more positions of the rail profile. The measurement signals are preferably acquired by means of the linear detection device. Two adjacent evaluation positions and / or strain sensors can be spaced along the track rail at a maximum distance of 50 m, in particular a maximum of 10 m, in particular a maximum of 5 m, in particular a maximum of 2 m, and / or at least 0.1 m, in particular a minimum of 0.3 m, in particular a minimum of 0.6 m, in particular a minimum of 1 m, in particular a minimum of 2 m. This ensures a particularly high measurement resolution with a simultaneously long measuring section.

[0030] Preferably, the distance between two adjacent strain sensors is dimensioned such that they can be arranged on the track at the distance of two adjacent sleepers and / or at half the distance between two adjacent sleepers. The distance between the strain sensors can be increased by a compensation factor, particularly in the range of 1% to 50%, and more specifically 5% to 20%, of the target distance, particularly the sleeper spacing, to ensure precise positioning of the strain sensors even with tolerances in the sleeper spacing. Furthermore, the measurement signals can be used to determine the degree of compaction of the ballast bed, the condition of the track ballast, and / or the detection of voids in the ballast bed.A reduced degree of compaction can be determined from the measurement signals by observing that the change in strain under load on the track, particularly the rail, especially with a vertical load component, is particularly large, especially compared to a reference measurement signal. The reference measurement signal may have been determined at the same position, particularly using the same strain sensor, at an earlier time, or it may have been generated by a measurement signal at a different measurement position or from a distant strain sensor. A void in the ballast bed is recognizable by the detection of a permanent change in strain that increases over time and / or by the fact that, under a sudden load, especially with a vertical load component, the resulting sudden change in strain is particularly large.The underlying principle is that the track sleeper supporting the track rail can sink into the track bed in the event of a hollow section, or is no longer supported by the track bed with the required stiffness.

[0031] Contamination of the ballast bed can be recognized by a change in the expansion rate under a given load, especially a reduction in the case of crusting.

[0032] Reduced ballast quality can lead to decreased ballast stiffness and / or damping. Reduced ballast quality, particularly due to wear, can be characterized by increased or significantly decreased strain change and / or an increased strain rate, especially under impact loading. Severe ballast wear can result in a significantly increased stiffness of the ballast bed, thereby considerably reducing rail strain under vertical load.

[0033] Based on the wave transit time in the ballast bed, which can be determined using the measurement signals, conclusions can be drawn about a degradation of the ballast quality and / or the compaction state of the ballast bed.

[0034] According to another aspect, the at least one track rail can be loaded to determine the condition of the track bed, and the measurement signals can be recorded when the track rail is loaded. Preferably, the loading is applied as a specific load, in particular with a defined load height and / or orientation, and / or mechanically, in particular by contact with the at least one track rail and / or the at least one track sleeper and / or the track bed. The loading can be applied to the track rail on which the at least one strain sensor is located and / or to the opposite track rail. The loading can be static, in particular quasi-static, or dynamic, in particular a single impact or multiple oscillations, in particular vibrating. Loading is understood to mean an external influence on the track.As an alternative to mechanical stress, the track, especially the track rail, can be subjected to thermal stress, particularly by heating.

[0035] Determining the condition of the track bed, particularly by means of an electronic evaluation unit, is preferably carried out based on the measurement signals recorded during loading and on the specific load, in particular on the defined load height and / or orientation. The loading of the track bed is preferably carried out by applying a test force, in particular to at least one track rail, particularly by means of at least one test force device providing the test force. The test force or the specific load is preferably a defined force, in particular a known, in particular set and / or adjustable, in particular controllable and / or adjustable, force and / or a force recorded, in particular with regard to load height and / or orientation. The test force or the specific load preferably has a horizontal and / or upward and / or downward force component. In particular, the test force or the specific load can beThe specified load can be oriented exclusively horizontally and / or vertically. The test force or the specified load can be directed exclusively upwards and / or downwards, in particular with or without a horizontal force component. The at least one test force device can be designed accordingly. The test force or the specified load can, in principle, be applied directly to a track rail, a track sleeper, and / or the track bed, in particular by means of a test force contact device, for example, a gripper and / or a plunger and / or a roller.

[0036] The properties can alternatively or additionally be determined by evaluating changes in expansion due to natural loads, for example through thermal expansion and / or the dead weight of the track grid.

[0037] According to another aspect, the loading of at least one track rail is carried out by means of a track construction device, in particular by means of a lifting and aligning unit and / or by means of a dynamic track stabilizer, especially via hydraulic cylinders. A defined test force is preferably applied. The track construction device can be a component of a track construction vehicle. Loads with a horizontal and / or vertical load component can be exerted on the track, in particular the track rail, by means of the lifting and aligning unit and / or the dynamic track stabilizer. The loading can be static, in particular quasi-static. The measurement signals can be recorded when the track, in particular the track rail, is loaded but not moving, in particular when it is at rest. Alternatively, the loading can be dynamic. The measurement signals can be recorded during movement of the track.The measurement signals can be acquired while the track, especially the rail, is in motion, particularly when it is set into vibration. Dynamic excitation can also occur through impact loading. The measurement signals acquired under static loading are predominantly characterized by the stiffness of the track bed. The measurement signals acquired under dynamic loading are characterized by the stiffness and / or damping of the track bed. Evaluating the measurement signals under different loading conditions, especially static and dynamic loading, allows for a particularly precise determination of the track bed's condition.

[0038] According to another aspect, at least one track rail can be subjected to the weight of a rail vehicle traveling over it, in particular a passenger vehicle and / or a work vehicle, especially a track construction vehicle and / or a measuring vehicle. Measurement signals can be recorded under such a load. Preferably, the weight of the respective rail vehicle is known, in particular the respective wheel load. Alternatively, the weight of the rail vehicle, in particular the respective wheel load, can be determined, especially by means of at least one of the strain sensors. Particularly when comparing the measurement signals of different strain sensors, the evaluation of the absolute magnitude of the load is optional. The condition can also be determined, for example, simply by comparing the strain changes of the different strain sensors with each other.

[0039] The condition of the track bed can be altered alternatively or additionally by applying load to the track, in particular to at least one rail, using any loading device, for example, a vibration generator (especially a mobile one) and / or a linear actuator. In a particularly simple loading scenario, the load can be applied manually, in particular by striking the rail with a hammer.

[0040] According to another aspect, the condition of the track bed during a track tamping operation, particularly before, during, and / or after the operation, can be documented. The resulting condition of the track bed and / or the achieved improvement in its condition can serve as a criterion for releasing the track for rail traffic and / or for the completion or continuation and / or acceptance of the maintenance work and / or for a damage analysis and / or for the remuneration of the maintenance work. The documentation information can be stored in a data storage device of the evaluation unit and / or transmitted to the track maintenance machine, in particular the tamping machine, and / or to the control center. Preferably, the documentation information from the evaluation unit is stored together with other documentation information from the track maintenance machine, in particular in a data storage device of the track maintenance machine.Alternatively or additionally, based on the specific characteristics, separate, in particular additional, documentation of the execution, in particular of the scope and / or results, of the track construction measure can be carried out, in particular separate from documentation generated by the track construction machine.

[0041] According to another aspect, at least one maintenance measure is initiated based on the specific condition of the track bed, particularly if a defect exists. Specifically, the maintenance measure can be carried out at the location where the defect was identified. The maintenance measure may include track bed compaction. The maintenance measure can be carried out locally, for example, by tamping under individual sleepers. This counteracts the spread of damage and makes the maintenance measures particularly time-efficient and economical.

[0042] According to another aspect, at least one maintenance measure is controlled based on the specific condition of the track bed. This control can occur during and / or between work steps of the maintenance measure, in particular by initiating the continuation or intensification of the maintenance measure depending on the specific condition. For example, the condition can be recorded after a track tamping cycle, and this information is used to determine whether or not at least one further track tamping cycle is carried out. For this purpose, the specific condition can be transmitted to the track maintenance machine during the maintenance measure.

[0043] Preferably, the maintenance measure is controlled based on the track's characteristics or measurement signals in such a way that the load on the track and / or an adjacent component, for example, a track signaling system and / or a switch and / or a balise, does not exceed a predetermined load limit. For example, the energy introduced into the track by a dynamic track stabilizer can be controlled in such a way that the track, in particular the ballast bed, and / or the adjacent component, for example, the track signaling system or elements of the signaling and safety technology, are not damaged. The strain sensors can serve as a means of detecting the loads introduced into the track, in particular the rails.

[0044] Alternatively or additionally, the rail transport system, in particular a section of track, can be controlled based on the specific condition of the track bed. For example, depending on the condition, the track section can be closed, its maximum permissible speed can be restricted, or it can be reopened after maintenance work. Another aspect is that the evaluation of the measurement signals can be position-based. The position of the specific condition can be determined using a data set that assigns position information to the respective strain sensor, particularly along the track and / or in a global coordinate system. For example, a specific kilometer marker on a track and / or a position in a geocentric coordinate system can be assigned to the respective strain sensor. The data set can be stored in the evaluation unit, in particular in its data storage.Alternatively, the data set can be stored in the central computing unit.

[0045] According to one aspect, the frequency, in particular the number of recurrences, especially the recurrence rate, of a defect can be evaluated in relation to its location. For example, it can be determined how often, especially over a specific period of time, a defect such as a void and / or an insufficient degree of compaction has occurred at a particular location. By comparing this with a corresponding threshold value, a decision can be made as to whether the cause should be analyzed and / or whether more extensive maintenance measures should be initiated, such as the rehabilitation of a larger area of ​​the track bed and / or the rehabilitation of the track substructure.

[0046] A further object of the invention is to create an improved device for determining the condition of a track bed, which in particular provides track bed condition information with particular temporal and / or spatial flexibility, and / or contributes to increased efficiency and safety of a rail transport system designed with this device. This object is achieved by a device for determining the condition of a track bed, in particular the quality of a ballast bed, comprising at least one strain sensor and an electronic evaluation unit configured to determine the condition of the track bed based on measurement signals from the at least one strain sensor, wherein the at least one strain sensor is mounted on a track rail to detect rail strain. The device is preferably further developed with at least one of the features described above in connection with the method.The advantages of the device can correspond to the advantages of the method.

[0047] The invention also relates to a rail transport system with such a device.

[0048] Preferably, the device comprises several strain sensors, in particular at least 50, in particular at least 100, in particular at least 250, in particular at least 500, in particular at least 1,000, and / or a maximum of 10,000, in particular a maximum of 5,000, in particular a maximum of 2,000, of the strain sensors. The strain sensors are preferably arranged at intervals along the track rail.

[0049] Preferably, the at least one strain sensor, in particular the multiple strain sensors, in particular all strain sensors or a large proportion of the strain sensors, are fiber optic strain sensors, in particular fiber Bragg grating sensors. Further features, details and advantages will become apparent from the following description of an exemplary embodiment with reference to the figures. The figures show:

[0050] Fig. 1 shows a schematic representation of a railway transport system with a device for determining the condition of a track bed, comprising several strain sensors for detecting rail strain on a track rail and an electronic evaluation unit for determining the condition of the track bed based on measurement signals from the at least one strain sensor, wherein a track construction vehicle is arranged on the track, or

[0051] Fig. 2 shows a schematic representation of the rail transport system with the device, wherein a transport vehicle is arranged on the track.

[0052] Figures 1 and 2 describe an embodiment of a device 1 for determining the condition of a track bed 2.

[0053] The device 1 is integrated into a rail transport system 3. The rail transport system 3 comprises a rail network with a plurality of track sections 4. Each track section 4 has a track grid 5 with track sleepers 6 and track rails 7 arranged on it. The track grid 5 rests on a track bed 2 designed as a ballast bed. Alternatively, the track bed 2 can be a solid, ballastless bed. The track section 4 can include an overhead line 8 for supplying rail vehicles 9 with electrical energy. The respective rail vehicle 9 can be a transport vehicle 9.1 or a work vehicle 9.2, in particular a track construction vehicle, a maintenance vehicle and / or a measuring vehicle. The rail vehicles 9 can alternatively have their own energy supply, for example, a fuel supply. The respective rail vehicle 9 comprises a bogie 10 with track wheels 11 on several axles 12.

[0054] The track bed 2 can have different properties, in particular quality states, for example a target state in which the track bed 2 is operational, or a defective state in which a maintenance measure is required.

[0055] In a state of deficiency, damage to the track bed 2 may be present, for example an insufficient degree of compaction 13, a hollow layer 14, insufficient ballast quality 15 or contamination 16.

[0056] An integrity defect of the rail transport system 3, which is not a defect in the condition of the track bed but can affect it, can, for example, consist of a defect 18 in a track substructure 17, in particular a spot with insufficient load-bearing capacity or stability.

[0057] The device 1 has a linear detection means 19 and an electronic evaluation unit 20.

[0058] The linear detection means 19 comprises a plurality of strain sensors 21, in particular at least 20, in particular at least 50, in particular at least 100, in particular at least 200, in particular at least 500, in particular at least 1,000, and / or a maximum of 10,000, in particular a maximum of 5,000, in particular a maximum of 3,000, of the strain sensors 21. The at least one strain sensor 21, in particular all strain sensors 21, are preferably designed as fiber optic sensors, in particular as fiber Bragg grating sensors.

[0059] The detection means 19 can have one or more optical fibers. Preferably, at least one, in particular exactly one or more, of the optical fibers is equipped with the at least one strain sensor 21 and / or at least one, in particular exactly one or more, of the optical fibers is designed without a strain sensor 21, particularly for transmitting data.

[0060] The strain sensors 21, in particular the number mentioned above, are preferably formed on a one-piece detection means 19, in particular by a single or more optical fibers.

[0061] The detection device 19 can also include at least one, in particular several, electrical signal lines.

[0062] The multiple optical fibers and / or the at least one electrical signal line can be bonded together to form the detection element 19, in particular by means of a carrier material, especially an insulating material, in particular by being embedded in it and / or encased by it and / or bonded together by it. The evaluation unit 20 can be in signal communication with the multiple strain sensors 21, in particular to evaluate the measurement signals acquired by them. For this purpose, the evaluation unit 20 is preferably in signal communication with all strain sensors 21 of the detection element 19 and / or with at least 50, in particular at least 100, in particular at least 200, in particular at least 500, and / or a maximum of 10,000, of the strain sensors 21. The evaluation unit 20 can include a signal converter for converting optical signals from the strain sensors 21 into electrical signals.

[0063] The evaluation unit 20 can be in signal communication with a central computing unit 22, in particular a control center 23, of the rail transport system 2. The signal communication 24 is preferably wireless. For this purpose, the evaluation unit 20 can have a radio module 25.

[0064] Preferably, the device 1 has two linear detection means 19, each attached to one of the track rails 7. The evaluation unit 20 can be in signal communication with the strain sensors 21 of one or more, in particular both, detection means 19.

[0065] The work vehicle 9.2 can be equipped with a load unit 26, which is separate from the track wheels 11, for exerting a test force F on the at least one track rail 7. This load unit preferably has a force component oriented horizontally and perpendicular to the longitudinal direction 30 of the rail. The load unit 26 can, for example, be a lifting and aligning unit 26.1 and / or a dynamic track stabilizer (not shown). Alternatively, the work vehicle 9.2 can be a measuring vehicle, which is specifically designed to apply a defined vertical load, particularly with a known weight force, to the track rails 7 via the track wheels 11.

[0066] The work vehicle 9.2 can have at least one track tamping unit 27 for compacting the ballast bed. Preferably, the work vehicle 9.2 is a track tamping machine.

[0067] The work vehicle 9.2 can be in contact with the control center 23, especially wirelessly, via signal.

[0068] The work vehicle 9.2 can alternatively or additionally be in signal communication with the evaluation unit 20.

[0069] The detection means 19, in particular the strain sensors 21, preferably extends over a measuring distance 31 with a length L in a range of 100 m to 10 km, in particular from 500 m to 5 km, in particular from 1 km to 3 km.

[0070] The rail vehicle 9, in particular the work vehicle 9.2, especially the track tamping machine, may have a control unit 28 for controlling the track tamping unit 27 and / or the lifting and aligning unit 26.1. A corresponding control unit may be provided for controlling the dynamic track stabilizer. The control unit 28 may be configured to control and / or document the work carried out on the track bed 2, in particular the scope of the measures taken. The control unit 28 may have an electronic processor 28.1 for processing control commands and / or documentation information and / or a data storage device 28.2 for storing the documentation information.

[0071] The functioning of the method or device 1 for determining the condition of the track bed 2 is as follows:

[0072] The linear detection devices 19 are attached to the track rails 7, particularly in the area of ​​the rail fastenings, and are in particular clamped and / or bonded in place. The strain sensors 21 provide measurement signals, in particular in the form of light signals. The measurement signals from the strain sensors 21 are read out and processed by the evaluation unit 20.

[0073] Preferably, the measurement signals from the strain sensors 21 are first evaluated and stored in a state in which the railway system 3, in particular the track bed 2, exhibits a target state, especially without defects. Corresponding measurement signals can be stored as reference values ​​in a data storage device 20.2 of the evaluation unit 20 or the control center 23.

[0074] The measurement signals of the strain sensors 21 are preferably read out continuously and / or at specific and / or manually and / or automatically determined times and / or at fixed time intervals, for example at a frequency of at least 1 / day, in particular at least 1 / hour, in particular at least 1 / minute, in particular at least 1 Hz, in particular at least 10 Hz, in particular at least 100 Hz, in particular at least 1 kHz, and / or at most 1 MHz, in particular at most 1 kHz. The condition of the track bed 2 can be determined on the basis of the measurement signals, in particular according to the timing of the measurement signal acquisition.

[0075] Whether the track bed 2 is in a target state or a deficient state can be determined by comparing the respective current measurement signal of a strain sensor 21 with other measurement signals, in particular at least one neighboring strain sensor 21 and / or with a previous measurement signal, in particular from at least one of the reference values, in particular from the same strain sensor 21 and / or another strain sensor 21, and / or based on a time course of at least one of the measurement signals, in particular the rate of change of the measurement signals.

[0076] The hollow layer 14 is recognizable, for example, by the fact that under a vertical load on the track rail 7, in particular by the weight force G of a rail vehicle 9 traveling over the track rail 7, a particularly strong deflection of the track rail 7 results, especially compared to a deflection with an intact track bed 2, without the hollow layer 14. The correspondingly larger strains can be detected by means of a strain sensor 21 arranged in the area of ​​the hollow layer 14. The hollow layer 14 can also be recognized by the fact that a change in strain is greater and / or occurs over a longer period than with adjacent strain sensors 21 that are arranged in an area without the hollow layer 14.

[0077] A load on the track rail 7 can also be applied by exerting a test force F on the track rail 7 using the loading unit 26, in particular by means of the lifting and aligning unit 26.1 and / or by means of the dynamic track stabilizer. This introduces forces, especially vibrations, into the track rail 7, leading to elongations in the track rail 7. These elongations depend on the bearing forces and thus on the condition of the track bed 2. A void 14 results in altered bearing forces and thus affects the measurement signals.The strains introduced into the track rail 7 by means of the dynamic track stabilizer are particularly strongly affected by the condition of the track bed 2, since the load is introduced into the track bed 2 in a locally focused manner, meaning that the stiffness of the track bed 2, which is decisive for the condition, has a correspondingly focused influence on the rail strain and thus on the measurement signals.

[0078] Areas 13 with insufficient compaction of the track bed 2, similar to the hollows 14, also result in reduced stiffness of the track bed 2. With an insufficient degree of compaction 13, the change in strain or measurement signal is higher and / or slower than with a highly compacted, stiff ballast bed. Unlike hollows 14, areas 13 with insufficient compaction are more extensive. The effects on the measurement signals are less pronounced than with hollows 14. However, increased strain changes or changes in the measurement signal can be determined not only at one strain sensor 21, but at several strain sensors 21 or at several positions along the track rail 7.

[0079] Contaminants 16 can lead to increased stiffness and thus to a reduced change in the measurement signal or strain of the track rail 7 under a load, particularly a vertical one. Contaminants 16 typically occur over a large area and can therefore also be detected by several strain sensors 21.

[0080] Areas of reduced ballast quality 15, particularly worn track ballast, are generally very extensive, and can extend over more than 25 m, more than 50 m, and more than 100 m along track section 4. With reduced ballast quality 15, the track bed 2 may exhibit reduced stiffness and / or reduced damping. Strain changes tend to occur with increased amplitude and / or higher speed.

[0081] It is particularly preferred that the condition of the ballast bed be determined and / or documented during and / or after and / or before a track tamping operation. In particular, the measurement signals obtained during the compaction of the ballast bed can be used to determine the condition of the track bed 2, especially due to the loads acting between the track construction machine and the track rails 7.

[0082] Preferably, the extent to which the track maintenance process, in particular the track tamping process, has improved the condition of track section 4, especially the track bed 2, and / or to what condition the condition of the track bed 2 has been adjusted, in particular improved, as a result of the track construction process is documented. This documentation can be used for acceptance purposes, as a prerequisite for the release of track section 4, and / or for the remuneration of the track construction process. The documentation of the condition and / or change in condition determined according to the procedure is preferably carried out in combination with documentation of the track construction process, in particular the track tamping process, especially by the track construction machine. The combined documentation increases the reliability of the information. The documentation information is preferably stored on the data storage device 28.2 of the control unit 28.The evaluation unit 20 can be in signal communication with the control unit 28, in particular wirelessly, especially directly and / or via the control center 23, in particular the central computing unit 22.

[0083] Preferably, the rail transport system 3, in particular the at least one rail vehicle 9, is controlled depending on its specific characteristics, especially by means of the interlocking system 23. For this purpose, relevant information, in particular the measurement signals and / or characteristics information, can be transmitted from the evaluation unit 20 to the control center 23. The characteristics information can be checked to determine whether the safe operation of the rail transport system 3 is ensured or not. If the characteristic defect prevents safe operation, the affected rail vehicle 9 and / or the track 4 can be blocked from operation or subjected to a speed restriction.

[0084] Depending on the result of the condition assessment, track construction work, in particular maintenance work, can be initiated. For example, the work vehicle 9.2, in particular the track tamping machine, can be sent to the determined position of the insufficiently compacted track bed 2 to carry out ballast compaction. The position of the respective condition defect can preferably be determined using a data set that assigns corresponding position information to the respective strain sensor 21. The data set can be stored in the data memory 20.2. The condition defect, in particular the damage, determined on the basis of the at least one measurement signal can thus be clearly assigned to the location of the respective detecting strain sensor 21. This makes maintenance measures particularly targeted and economical.

[0085] Particularly preferably, a maintenance measure is initiated and / or controlled based on the specific condition. Depending on the result of the condition assessment, track construction work, in particular maintenance work, especially a track tamping operation, can be initiated. For example, the work vehicle 9.2, in particular the track tamping machine, can be positioned at the point in the track bed 2 with an insufficient degree of compaction 13 or with voids 14 in order to carry out ballast compaction.

[0086] The maintenance measure can be controlled by specifying, based on the track bed's condition, the intensity with which the track construction process, in particular the tamping operation, is to be carried out. Alternatively or additionally, the condition of the track bed 2, in particular the degree of compaction, can be determined during or immediately after a tamping cycle in order to control the track construction vehicle 9.2, in particular the tamping machine, depending on the condition, to carry out a further track construction step, in particular another tamping cycle. The duration of the tamping cycle, in particular the waiting time, can be adjusted to the ambient conditions and / or the existing condition and / or the target condition to be achieved.

[0087] Preferably, the specific condition is evaluated to determine the frequency, particularly per unit of time, of a defect at a specific location along track 4. If defects occur frequently in the same area, especially at the same location, and particularly at short intervals, a root cause analysis can be initiated. In particular, a defect in the track substructure 17 could be present. Specific maintenance measures, for example, to repair the track substructure 17, can then be initiated, depending in particular on the results of the root cause analysis.

[0088] Determining the condition of the track bed 2 using the strain sensors 21, in particular the fiber optic strain sensors, especially using the linear detection device 19, ensures precise location-based knowledge of the condition of the track bed 2. This allows maintenance measures to be carried out in a particularly targeted, early and therefore economical manner.

[0089] Regular monitoring of the track bed's condition is enabled, allowing for the early detection of degradation and enabling the initiation of countermeasures, particularly maintenance measures, before damage occurs, spreads, or serious safety risks arise. The method for determining the track bed's condition, or the device 1, thus ensures particularly safe operation of the rail transport system 3.

Claims

Patent claims 1. Method for determining the condition of a track bed (2), in particular the quality of a ballast bed, comprising the steps: 1.1 Applying a load to at least one track rail (7) with a defined load height and load orientation, 1.2 Acquisition of measurement signals from at least one deformation sensor (21) when the track rail (7) is loaded, 1.3 Determining the condition of the track bed (2) based on the measurement signals recorded during loading, 1.4 wherein the measurement signals are acquired by means of at least one dew point sensor (21) which is attached to a track rail (7) to detect rail dew point.

2. Method according to claim 1, characterized in that the at least one damping sensor (21) is a fiber optic damping sensor, in particular a fiber Bragg grating sensor.

3. Method according to claim 1 or 2, characterized in that the condition of the track bed (2) is determined on the basis of the measurement signals of several deformation sensors (21), in particular on the basis of at least 50 strain sensors (21) which are arranged spaced apart from each other along the track rail (7).

4. Method according to claim 3, characterized in that the multiple deformation sensors (21) are components of a linear detection device (19) which extends over a measuring section (31) along the track rail (7) with a length (L) of at least 100 m.

5. Method according to claim 3 or 4, characterized in that the condition of the track bed (2) is determined on the basis of the measurement signals at at least 25 evaluation positions spaced apart from each other along the track rail (7).

6. Method according to one of the preceding claims, characterized in that a degree of compaction (13) of the ballast bed is determined on the basis of the measurement signals and / or the ballast quality (15) is determined and / or a void (14) of the ballast bed (2) is detected.

7. Method according to one of the preceding claims, characterized in that the loading is carried out mechanically by contact with the at least one track rail (7), in particular by means of a gripper and / or a plunger and / or a roller.

8. Method according to claim 7, characterized in that the at least one track rail (7) is loaded by means of a lifting and aligning unit (26.1) and / or a dynamic track stabilizer.

9. Method according to claim 7 or 8, characterized in that the at least one track rail (7) is loaded by the weight force (G) of a rail vehicle (9), in particular a transport vehicle (9.1) and / or a work vehicle (9.2), traveling over the track rail (7).

10. Method according to any one of the preceding claims, characterized by documenting, in particular a change, the condition of the ballast bed (2) during a track tamping operation.

11. Method according to one of the preceding claims, characterized by initiating a maintenance measure based on the specific condition of the ballast bed (2).

12. Method according to one of the preceding claims, characterized by controlling a maintenance measure based on the specific properties of the ballast bed (2).

13. Method according to one of the preceding claims, characterized by position-related evaluation of the frequency of a defect.

14. Device (1) for determining the condition of a track bed (2), in particular the quality of a ballast bed, comprising 14.1 at least one strain sensor (21) for detecting measurement signals when the track rail (7) is loaded with a defined load height and load orientation and 14.2 an electronic evaluation unit (20) designed to determine the condition of the track bed (2) based on the measurement signals recorded during loading and on the defined load level and load orientation, 14.3 wherein the at least one strain sensor (21) for detecting rail strain is attached to a track rail (7).

15. Device (1) according to claim 14, characterized by several strain sensors (21), in particular at least 50 of the strain sensors (21), which are arranged apart from one another along the track rail (7).

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