Method for locating at least one discontinuity of a wheel-trackway contact

Abstract

The invention relates to a method for locating at least one discontinuity of a wheel-trackway contact along a wheel-trackway contact trajectory when a wheel (11) of a rail vehicle or train passes over one or more trackway components (1) of a railway track, in which method at least one sensor signal is detected which represents the time profile of a mechanical-dynamic load on the trackway component (1) on the basis of a wheel-trackway interaction in at least one spatial direction, wherein the detected sensor signal comprises a first and a second local extremum (A, B) which are assigned known reference features of the railway track, in particular of the trackway component (1), which reference features are arranged at a regional distance from one another, and wherein at least a third local extremum (C) of the sensor signal occurring at a temporal distance from the first and the second local extremum (A, B) is determined as the discontinuity of the wheel-trackway contact, and the position of the discontinuity is determined according to the temporal distance of the local extrema (A, B, C) and preferably on the basis of the known regional distance between the reference features.

Description

[0001] Method for locating at least one discontinuity of a wheel-track contact

[0002] The invention relates to a method and a device for locating at least one discontinuity of a wheel-track contact along a wheel-track contact trajectory when a wheel of a rail vehicle or train passes over one or more track components of a railway track, in which at least one sensor signal is detected which represents the temporal course of a mechanical-dynamic stress on the track component due to a wheel-track interaction in at least one spatial direction.

[0003] The discontinuity of the wheel-track contact along the contact trajectory when a rail vehicle passes over track components such as switches and crossings is a major cause of characteristic dynamic loading and the resulting wear on these components. Particularly in the area of ​​the frog of switches, discontinuities in the running edge lead to shock loads and increased material stress. Reliable condition monitoring and wear assessment of switch components are therefore of key importance for ensuring safe and trouble-free rail traffic.

[0004] Various approaches to detecting and quantifying wear are known in the state of the art. Regular visual inspections by qualified personnel are common practice, with visible signs of wear being assessed and documented. The disadvantages of this approach are the high personnel costs and the limited significance of purely visual assessments regarding the actual progression of wear.

[0005] In addition, mobile measuring devices are used to manually record geometric parameters such as elevation, ramp profile, and flatness. Examples include rulers, calipers, measuring wedges, and feeler gauges. The advantage is the detailed recording of relevant parameters; the disadvantages are the continued high personnel and time expenditure, as well as the fact that they can only be viewed occasionally.

[0006] Another option is special measuring trains equipped with extensive sensor technology. As they pass over the tracks, they record various measurements that can be used to determine the level of wear.

[0007] The advantage is that longer sections of the route can be recorded in a single crossing, but the disadvantage is the complex and cost-intensive equipment and the only sporadic availability of the measurement data.

[0008] Equipping regular locomotives or railcars with wear-related sensors is also being practiced. This allows for continuous monitoring without requiring separate test runs. The disadvantages are the high initial equipment costs and the on-board data storage and transmission.

[0009] Stationary monitoring solutions concentrate on neuralgic points in the track network. For example, sensor arrays record the rolling quality via various measuring or support points on the frog and allow conclusions to be drawn about the wear condition of the frog based on the dynamic reactions during travel. To take the influence of travel speed into account, this is estimated separately using additional sensors. Cross-tip sensors detect approach or the impact intensity of the wheels in the frog area due to incorrect adjustment of the wheel guides or wear on the frog. The development of wear can be derived from the change in the measured values ​​over time. The continuous, fixed recording of relevant parameters is advantageous; the disadvantages are the stationary equipment and maintenance costs and one-sided system monitoring.

[0010] The document DE 102004014282 A1 discloses a method for the diagnosis and condition monitoring in the overrun area of ​​switches, rigid frogs and crossings. When a train passes over the switch at a certain speed and direction, the acceleration generated by the train is measured at the frog using an acceleration sensor installed there. In addition, the settlement of a sleeper in the area of ​​the frog caused by the train passing over is determined using a distance measuring device. A data acquisition system processes the signals from the acceleration sensor, the distance measuring device as well as the train speed and direction, stores them and evaluates them with regard to whether limit values ​​have been exceeded.The method uses the relationship between increasing accelerations at the frog due to increasing geometric deviations and the progression of wear in order to assess the wear condition and initiate maintenance measures in good time.

[0011] Publication EP 3458331 A1 discloses a method for monitoring a track component laid in railway construction, such as a frog, in which a sensor, preferably a strain sensor, is attached to the switch. This sensor continuously measures the strain of the switch component over time, in particular before, during and after rail vehicles pass over it. The data is segmented, i.e. divided into the sections before, during and after the train passes over it. From the segmented data, conclusions can be drawn about the condition of the switch by analyzing the characteristic patterns. In particular, changes over longer periods of time that indicate progressive wear can be recorded. The evaluation is carried out using statistical methods and envelope curves, with computer models being used to separate out various influencing factors and, for example, to identify and classify them.A distinction can be made between damage caused by out-of-round wheels and worn switch faces. By comparing the wear condition with the nominal data of an intact switch, the wear condition can be determined and the remaining service life predicted. However, no evidence is provided for the location of a discontinuity, although this represents a crucial and solid criterion for assessing the condition and geometry of a track component.

[0012] The state-of-the-art methods for monitoring the wear of switch components have various disadvantages. Mobile solutions are typically interval-based and carried out at set time intervals. This means that critical wear conditions may not be detected too late. In addition, these approaches require a lot of personnel and, depending on the time and duration of use, can lead to disruptions to regular rail operations. While stationary monitoring solutions enable continuous monitoring, they often require a lot of instrumentation and are therefore expensive. On the other hand, equipping individual neuralgic points in the track network with individual sensors requires evaluation methods that only allow for limited accuracy and informative value.

[0013] The present invention is therefore based on the object of creating a stationary monitoring system for the wear of rigid frogs in switches and other track components affected by changes such as wear, which overcomes the disadvantages of the known solutions. The system should be based on sensors that are as robust and simple as possible, which enable reliable statements to be made even with small amounts of data or simple sensor signals in railway operation. At the same time, the number of sensors required should be reduced to a minimum, ideally to just one sensor for monitoring one or more conditions, e.g. a frog, in order to limit the instrumentation and maintenance effort. In addition, the aim should be to provide a better quality statement about the condition of a track component than has been achieved with previously known, more complex methods.In addition, the monitoring system should be efficient and easy to install to enable quick and cost-effective installation and to minimize disruption to railway operations during installation.

[0014] To achieve this object, the invention provides, according to a first aspect, a method for locating at least one discontinuity of a wheel-track contact along a wheel-track contact trajectory when a wheel of a rail vehicle or train passes over one or more track components of a railway track, in which method at least one sensor signal is detected which represents the temporal course of a mechanical-dynamic stress on the track component due to a wheel-track interaction in at least one spatial direction, wherein the detected sensor signal has a first and a second local extremum which are assigned to known reference features of the railway track, in particular the track component, which are arranged at a spatial distance from one another,and wherein at least one third local extremum of the sensor signal occurring at a temporal distance from the first and second local extremum is determined as the discontinuity of the wheel-track contact and the position of the discontinuity is determined according to the temporal distance of the local extrema and preferably based on the known local distance of the reference features.,

[0015] The solution according to the invention enables efficient and reliable monitoring of the wear condition of switch components, in particular of the frog. By recording a sensor signal which represents the temporal progression of the mechanical-dynamic stress on the track component as one or more wheels of a rail vehicle pass over it, the position of a discontinuity in the wheel-track contact along the contact trajectory can be precisely determined. This allows conclusions to be drawn about structural and geometric conditions, such as the condition of the wheel and / or track component profile, since signs of wear can be reflected not only in the intensity of the sensor signal when the track rolls over the discontinuity, but also in a change in the position of the discontinuity as the track rolls over it.However, the intensity of the sensor signal increases not only with wear but also with the speed and weight of the rail vehicle. The inventive determination of the position or wear-related change in the position of a discontinuity is largely independent of weight and speed differences between rail vehicles and thus provides a direct and simple indicator of wear.

[0016] The solution according to the invention is also suitable for detecting newly developing or emerging damage as discontinuities in the recorded sensor signal, including their location. This includes both superficial damage, such as broken material in the area of ​​wheel-rail contact or so-called squats, as well as local structural damage, such as a fracture of a track component or locally inadequate support of a track component by the load-bearing substructure of the track.

[0017] A technical effect of the invention is that contact point detection or assignment is possible with just a single sensor when a wheel passes over several characteristic reference features and contact points or discontinuities spaced from one another in a known sequence, for example by measuring acceleration, strain, structure-borne noise or other physical quantities that can be referenced to reference features. This eliminates the need for complex synchronization of several sensors at different contact points along the direction of travel, which significantly reduces the instrumentation, calculation and maintenance effort. At the same time, high measurement accuracy and reliability are guaranteed.

[0018] A further advantage arises from the use of additional signal features which are caused as reference features by known geometric and mechanical features of the track or the switch due to the wheel-track contact along the contact trajectory and which appear in the sensor signal curve in chronological sequence as reference points or extremes. These signal features or signal components, which are not directly decisive for wear or other undesirable conditions, are not given any particular importance in known methods or are treated as interfering signal components. According to the invention, however, they serve as reference points for the temporal and / or spatial assignment of one or more detected discontinuities. The invention therefore enables, for example, a determination of the position of a wear-relevant, variable contact point or discontinuity, regardless of the specific sensor placement.It should be emphasized that the "location" and "position" or "position determination" of the discontinuity or the local extrema of the sensor signal are not limited to a purely spatial position, but can also involve a temporal component or a temporal position. Furthermore, it should be emphasized that local extrema for position determination also include those resulting from further processing of the sensor signal, such as integration over time.

[0019] The recorded sensor signal typically has several prominent local extrema (maxima or minima) that arise from the wheel passing over certain geometric or mechanical features of the switch or the wheel-track contact along the contact trajectory. Examples of such features can be rail profile changes, weld seams, insulation joints, reference features built into a component purely for referencing purposes, stiffness changes, attached masses, or similar. If the position of these features along the track component is known, they can be assigned to the corresponding local extrema, namely the first and second local extremum, in the sensor signal.

[0020] Based on the time interval between these reference points and the third local extremum, which also occurs in the signal and results from the desired discontinuity in the wheel-track contact, the position of this discontinuity can be deduced. If, for example, the time interval between a reference point and the discontinuity is known, the local distance between the corresponding reference feature and the location of the discontinuity can be calculated if the train's speed is known. The speed can be determined from the time interval between the first and second local extremum, which correspond to reference points assigned to reference features, taking into account the known local distance.

[0021] Basically, however, neither knowledge of individual absolute temporal differences between the occurrence of the local extrema nor the exact spatial position of the discontinuity is absolutely necessary in order to make a meaningful assessment of the wear condition or a wear forecast. Instead, the relative temporal positions of the local extrema to one another can provide sufficient indications of changes in the wheel-rail interaction and thus of wear progression. In particular, the relationship between the temporal position of the third local extremum, which is assigned to the discontinuity, and the first and / or second local extremum, which are caused by known geometric and mechanical features, allows conclusions to be drawn about the condition of the track component. If, for example, the relative position of the third extremum in the time domain shifts compared to the reference points, this indicates a displacement of the contact point orDiscontinuity and thus progressive wear. By observing and analyzing these relative temporal relationships during continuous rolling operations, conclusions can be drawn about the progression of wear based on known correlations. This allows trends and critical developments to be recognized early, and appropriate maintenance measures to be initiated. A more complex absolute location of the discontinuities can also be performed if necessary.

[0022] The geometric and mechanical features used as reference points can be arranged on either side of the discontinuity to be determined, viewed in the longitudinal direction of the rail, so that the discontinuity is located between the reference points. Alternatively, other arrangements are also possible, such as both reference points being located in front of the discontinuity in the longitudinal direction of the rail, or both reference points being located behind the discontinuity.

[0023] To determine the at least one sensor signal, at least one sensor is arranged on the track component directly, indirectly, e.g., via a mount, or in its immediate vicinity. The sensor does not have to be located in the immediate vicinity of the discontinuity to be detected; greater distances are also possible, as long as the sensor is capable of sensing the mechanical-dynamic stress emanating from the discontinuity and the reference features.

[0024] The at least one sensor can be designed as an acceleration, strain, deformation or structure-borne sound sensor.

[0025] Accordingly, a preferred embodiment of the invention provides that the at least one sensor signal is recorded as an acceleration signal or deformation signal which represents the time course of an acceleration, strain or other deformation of the track component caused by the crossing in at least one spatial direction. Advantageously, the acceleration or, for example, strain can also be recorded in two or three mutually perpendicular spatial directions and a multi-axis signal can thus be obtained. In the case of a single-axis measurement, the acceleration component is preferably recorded in the vertical direction, i.e. perpendicular to the track plane. In the case of two-axis recording, the measurement is preferably carried out in the vertical direction perpendicular to the track plane (z-direction) and in the lateral direction transverse to the longitudinal direction of the rail (y-direction). The evaluation of the multi-axis acceleration or, for example,The strain signal enables a detailed analysis of the wheel-rail interaction and a reliable detection of those discontinuities and reference features in the contact pattern that do not predominantly have an effect in one spatial direction. The acceleration components in the z and y directions can be considered individually or in combination. If, for example, local extrema in the z and y signals occur in a characteristic pattern or in a certain position at the same time or with a defined temporal offset, many more causes for a discontinuity can be determined from the ratio of the z:y extrema or from their temporal offset.

[0026] Alternatively, it can be provided that the at least one sensor signal is recorded as a deformation signal which represents the temporal progression of a local deformation of the track component in at least one spatial direction caused by the crossing. A suitable type of sensor for recording deformations is a strain gauge. By applying strain gauges to the surface of the track component, for example to the rail webs or the frog point, local deformations can be recorded precisely. The sensors are preferably positioned at locations which have pronounced deformation characteristics and are sensitive to discontinuities in the wheel-rail contact. Piezoelectric sensors can also be considered.

[0027] The track component is preferably designed as a rail switch or crossing with at least one wing rail, at least one sleeper or solid base and a rigid or movable frog and the discontinuity of the wheel-track contact is detected by the sensor signal during a wheel transfer between the wing rail and the frog tip. The frog represents a critical section in the wheel-rail system since this is where the guidance of the wheel changes, for example, from the wing rail to the frog tip. The initial transition, also referred to as the wheel transfer point, is particularly susceptible to impacts, wear and damage due to the high dynamic loads and the impact of a second offset contact point.

[0028] In the area of ​​the crossing there are four possibilities for overrun. In both straight and branching directions there is a wheel transfer from a wing rail to a crossing tip or vice versa, depending on the direction of travel. Preferably a consistent pattern is determined based on a correlation between local sequences of reference features and the temporal sequence of several assignable reference points in the sensor signal, which arises when a rail vehicle or train is traveling in a specific direction. The link between the sensor signal and the direction of travel enables discontinuities to be located precisely and also allows other known influencing factors, such as wheel geometry, to be quantified. Furthermore, by combining known sensor signals from all directions of travel, the operationally relevant actual geometric condition of the track component can be fully determined using just one sensor.

[0029] In connection with the location of the aforementioned wheel transfer point, known reference points or reference features arranged at a spatial distance from one another are of interest for the assignment of the first and second local extremum of the sensor signal. These are located in the direction of travel on both sides of the wheel transfer point and have distinctive geometric or mechanical features of the switch component with the most defined interaction possible with the wheel and thus produce characteristic sensor signals. The wing rail knee and a cross-sectional change in the frog have proven to be particularly suitable reference features of the track component, since these are easily assigned as first and second extremums and are detected particularly clearly with the sensor signal.In a preferred embodiment of the method, a so-called peak finder is used for the assignment. This peak finder searches for a corresponding pattern in the extrema of the sensor signal based on a pattern of reference points that depends on the reference features. However, other reference features can also be used, such as weld seams, reference features formed on a component exclusively for referencing purposes, stiffness changes, markers, attached masses, and the like.

[0030] Monitoring the wear condition of a track component based on the location of the discontinuity can be achieved, for example, by using a change in the position of the discontinuity over time until the end of its service life. Alternatively, the measured position of the discontinuity can be compared with the results of a numerical simulation of the track component.In the latter case, a preferred development of the invention provides that the mechanical-dynamic stress on the track component due to the wheel-track contact along the wheel-track contact trajectory is numerically simulated using a digital model of at least one wheel-track component pairing in order to obtain a simulated sensor signal, and that the position of the discontinuity is determined using the detected sensor signal and using the simulated sensor signal, and that a wear condition of the track component is preferably inferred from a change in the position of the discontinuity determined using the detected sensor signal in comparison to the position of the discontinuity determined using the simulated sensor signal.

[0031] If the measured position of the discontinuity deviates significantly from the simulated position, this indicates a wear-related change in the contact conditions. The type and extent of this deviation allow conclusions to be drawn about the specific wear condition of the track component. For example, a systematic shift of the wheel transfer points toward a wider and taller frog point may indicate progressive wear or plastic deformation in this area.

[0032] Comparison with numerical simulation offers the advantage of a model-based reference, which enables an objective and quantitative assessment of the wear condition. By adapting the model to the specific geometry and operating conditions of the monitored track component, a highly meaningful and reliable condition diagnosis can be achieved.

[0033] The mechanical-dynamic stress on a track component while a rail vehicle is passing over it depends on a variety of factors that can vary from wheel to wheel. In addition to manufacturing-related tolerances of the wheels and axles, the sinusoidal run of the wheel axles plays a particularly important role. This describes the periodic transverse movement of the wheels relative to the rail. Due to the random sinusoidal run or entry angle, the contact conditions in the area of ​​certain discontinuities, but also in the area of ​​some of the reference features used as reference points, can change from wheel to wheel and shift to a certain extent. In these cases, the position information for the discontinuity obtained from the sensor signal must be understood and evaluated as a probability distribution if the actual position is to be determined with particular accuracy.In order to take these influences into account and to make a more reliable statement about the actual state of wear of the track component, the invention provides, in a preferred embodiment, for the location of the discontinuity to be carried out for a plurality of wheels.

[0034] This is preferably done in such a way that when a plurality of wheels of one or more rail vehicles or trains pass over, the at least one sensor signal is recorded and the position of the discontinuity is determined for at least a subset of the wheels or for each wheel, and a probable position is deduced from an evaluation of positions of the discontinuity and a warning signal is preferably issued when a certain probable position is reached.

[0035] In other words, this means that when one or more rail vehicles pass over the track, a large number of individual results are obtained, each representing the position of the discontinuity for a specific wheel. Statistical evaluation of these individual results allows an estimate of the probable actual position of the discontinuity. Methods such as averaging or determining the median make it possible to reduce the influence of individual wheel factors and determine a representative position that reflects the general state of wear of the track component.Preferably, the evaluation comprises the formation of a moving average of the discontinuity positions over a predetermined period of time or a predetermined number of passes, wherein in the event of a shift or shift rate of a predetermined extent of the moving average, a conclusion is drawn as to a geometric or temporal limit value of a wear condition and a warning signal is issued.

[0036] Since the wheel-track contact depends considerably on the condition of the respective wheel, the invention opens up the possibility of monitoring the condition of the wheels passing over it in addition to the wear condition of the track component. This approach is based on the knowledge that the individual wear condition of a wheel is expressed in characteristic deviations of the position of the discontinuity from a value averaged across all wheels. The mean value is preferably a moving average over a predetermined period of time, for example one month, or a predetermined number of train passages. The wear condition of a wheel does not relate to the generally different diameters of the wheels of rail vehicles, since this does not have a significant influence on the location of the discontinuity in the method according to the invention.The wear condition of the wheel relates mainly to wear profiles which describe deviations from the original profile, a tapered wheel profile. For example, hollow wheels are transferred from the wing rail to the frog point considerably later in the direction of travel. A preferred embodiment of the invention provides in this context that the detection of the sensor signal and the determination of the position of the discontinuity take place as each wheel of the rail vehicle or train involved passes over it, and that a wear condition of this wheel is concluded from a deviation of a predetermined extent in the position of the discontinuity detected for a wheel from an average value or median for the position of the discontinuity determined from all wheels of the train, or from all wheels of several trains over a definable period of time.

[0037] The use of a mean or median as a comparison standard makes it possible to eliminate the influence of the general wear condition of the track component and to isolate the wheel-specific influences. Furthermore, the wheel-selective evaluation of the sensor signals contributes to increasing the informative value and reliability of wear monitoring overall. By identifying and separating wheels at risk, the influence of wheel irregularities on the determination of the wear condition of the track component can be reduced, thus improving the accuracy and robustness of the condition diagnosis.

[0038] In a further embodiment of the method, an improvement is achieved in that, for example, for a wheel at the location of a discontinuity, an exact and reliable measure of its travel speed is determined on the basis of the nearest reference features or reference points, so that, in combination with the location of the discontinuity, an even more precise geometric characteristic of wear or damage can be deduced from the intensity or a deflection of the sensor signal with regard to the area of ​​the discontinuity, taking into account the measure of the speed.

[0039] Sampling frequencies of simpler sensors, e.g., between 2 and 20 kHz, are sufficient for the present method to enable the position determination of a contact point or discontinuity with a geometric resolution of < 5 mm at speeds of up to 350 km / h. The method is preferably used from 20 km / h, and particularly preferably from 35 km / h. The measurement or sampling frequency of the sensor can, for example, be adapted depending on the speed of each rail vehicle.

[0040] According to a second aspect of the invention, a device is provided for locating a discontinuity of a wheel-track contact along a wheel-track contact trajectory when a wheel of a rail vehicle or train passes over at least one track component of a railway track, wherein the device is particularly suitable for carrying out the method according to the first aspect of the invention. The device comprises according to the invention:

[0041] - the at least one track component, at least one sensor mounted on the track component or in its vicinity for detecting a sensor signal representing the temporal progression of a mechanical-dynamic stress on the track component due to a wheel-track interaction in at least one spatial direction,

[0042] - a signal evaluation circuit to which the sensor signal is fed and which preferably has stored the local distance between two reference features of the travel path arranged at a known distance from one another within the measuring range of the sensor, wherein the signal evaluation circuit is set up to evaluate the sensor signal and to detect a first and a second local extremum which are assigned to the reference features of the travel path, and to detect a third local extremum of the sensor signal which occurs at a time interval from the first and the second local extremum and which is determined as the discontinuity of the wheel-travel path contact, wherein the position of the discontinuity can be determined in accordance with the time interval between the local extrema and preferably on the basis of the known local distance between the reference features.

[0043] Preferably, the at least one sensor is designed as an acceleration sensor or deformation sensor.

[0044] Preferably, the track component is designed as a rail switch or crossing with at least one wing rail, at least one sleeper or solid base and a rigid or movable frog, and the discontinuity of the wheel-track contact is a wheel transfer area on the wing rail and / or on the frog tip.

[0045] Preferably, the reference features of the guideway component are formed by a wing rail knee and a cross-sectional change of the frog.

[0046] Preferably, when a plurality of wheels of one or more rail vehicles or trains pass over, the signal evaluation circuit is designed to detect the sensor signal for at least a subset of the wheels or for each wheel and to evaluate it to determine the position of the discontinuity and to deduce a probable position from an evaluation of positions of the discontinuity and to output a warning signal when a certain probable position is reached.

[0047] Preferably, the evaluation comprises the formation of a moving average of the discontinuity positions over a predetermined period of time or a predetermined number of passes, wherein in the event of a shift or shift rate of a predetermined extent of the moving average, a conclusion is drawn as to a geometric or temporal limit value of the wear condition and a warning signal is issued.

[0048] Preferably, the signal evaluation circuit is designed to detect the sensor signal when each wheel of the rail vehicle or train involved passes over it and to evaluate it to determine the position of the discontinuity and to conclude a state of wear of this wheel from a deviation of a predetermined extent of the position of the discontinuity detected at a wheel from an average value or median for the position of the discontinuity determined from all wheels of the train, or from all wheels of several trains over a definable period of time.

[0049] The invention is explained in more detail below with reference to an exemplary embodiment shown in the drawing. In this drawing: Fig. 1 is a schematic representation of a rail switch, Fig. 2 is an enlarged representation of the rail switch in the area of ​​the wheel transfer point between the wing rail and the frog point, Fig. 3 is a schematic representation of the wheel-track contact in the area of ​​the wheel transfer point in cross section and Fig. 4 is a representation of the sensor signal.

[0050] In Fig. 1 the general components of a railway switch 1 are shown, namely stock rails 2, tongue rails 3, a rigid frog 4, wing rails 5 and check rails 6.

[0051] Fig. 2 shows an enlarged section of Fig. 1 in the area of ​​the frog 4 with the rigid frog tip 7, wherein the course of the wheel-track contact is indicated by the dotted lines 8 and 10. The wheel transfer point is designated 9. The cross-sectional view in Fig. 3 illustrates the wheel-track contact points 8 and 10 at the time of wheel transfer, in which the contact points are arranged in different areas of the running wheel 11.

[0052] In order to locate the discontinuity of the wheel-track contact caused by the wheel handover, an acceleration sensor (not shown) is arranged in the area of ​​the frog 4, for example on its underside or on the side of the web of a wing rail 5, which measures the mechanical-dynamic stress on the track component due to the wheel-track interaction in at least one spatial direction, preferably in the vertical direction. The sensor signal resulting from this when a wheel passes over is shown in Fig. 4. It can be seen that the sensor signal has several local extrema, for example a local first maximum A, a third local maximum C and a second local maximum B seen in the direction of travel.The first and the second local maximum are assigned to predetermined reference features of the switch by which these two extremes were caused, based on a known pattern, as reference points, namely the wing rail knee 12 and a cross-sectional change (not shown) of the frog 4. The reference features are arranged at a constant spatial distance from one another and the reference points in the sensor signal at a temporal distance, so that the location of the discontinuity can be determined from the occurrence of the third local maximum in relation to the occurrence of the first and / or second local maximum.

Claims

Patent claims:

1. Method for locating at least one discontinuity of a wheel-track contact along a wheel-track contact trajectory when a wheel (11) of a rail vehicle or train passes over one or more track components of a railway track, in which at least one sensor signal is detected which represents the temporal course of a mechanical-dynamic stress on the track component (1) due to a wheel-track interaction in at least one spatial direction, wherein the detected sensor signal has a first and a second local extremum (A, B) which are assigned to known reference features of the railway track, in particular of the track component (1), which are arranged at a spatial distance from one another, and wherein at least one sensor signal corresponding to the first and to the second local extremum (A,B) a third local extremum (C) of the sensor signal occurring at a time interval is determined as the discontinuity of the wheel-track contact and the position of the discontinuity is determined according to the time interval of the local extrema (A, B, C) and preferably based on the known local distance of the reference features.

2. Method according to claim 1, characterized in that the at least one sensor signal is detected as an acceleration signal which represents the temporal course of an acceleration of the travel path component (1) caused by the crossing in at least one spatial direction. 3 . Method according to claim 1 or 2 , characterized in that the at least one sensor signal is detected as a deformation signal which determines the temporal Represents the course of a local deformation of the track component (1) caused by the crossing in at least one spatial direction.

4. Method according to claim 1, 2 or 3, characterized in that the track component (1) is designed as a rail switch or crossing with at least one wing rail (5), at least one sleeper or solid base and a rigid or movable frog (4) and the discontinuity of the wheel-track contact during a wheel transfer between the wing rail (5) and the frog tip (7) is detected with the sensor signal.

5. Method according to claim 4, characterized in that the reference features of the guideway component (1) are formed by a wing rail knee (12) and a cross-sectional change of the frog ($) and are detected as assignable first and second extremum (A, B) with the sensor signal.

6. Method according to one of claims 2 to 5, characterized in that the detection of the acceleration or deformation signal comprises the detection of a vertical acceleration or deformation component and / or a horizontal acceleration or deformation component.

7. Method according to one of claims 1 to 6, characterized in that the mechanical-dynamic stress of the track component (1) due to the wheel-track contact along the wheel-track contact trajectory is numerically simulated with a digital model of at least one pairing of wheel-track component (1) in order to obtain a simulated sensor signal, and that the determination the position of the discontinuity is determined using the detected sensor signal and using the simulated sensor signal, and that a wear condition of the track component (1) is preferably inferred from a change in the position of the discontinuity determined using the detected sensor signal in comparison to the position of the discontinuity determined using the simulated sensor signal.

8. Method according to one of claims 1 to 7, characterized in that when a plurality of wheels (11) of one or more rail vehicles or trains pass over, the detection of at least one sensor signal and the determination of the position of the discontinuity for at least a subset of the wheels (11) or for each wheel (11) is carried out and a probable position is deduced from an evaluation of positions of the discontinuity and a warning signal is preferably output when a certain probable position is reached.

9. Method according to claim 8, characterized in that the evaluation comprises the formation of a moving average of the discontinuity positions over a predetermined period of time or a predetermined number of passes, wherein in the case of a shift or shift rate of a predetermined extent of the moving average, a conclusion is drawn as to a geometric or temporal limit value of a wear condition and a warning signal is issued. 10 . Method according to one of claims 1 to 9, characterized in that the detection of the sensor signal and the determination of the position of the discontinuity when passing each wheel ( 11 ) of the rail vehicle or train involved and a wear condition of this wheel (11) is inferred from a deviation of a predetermined extent of the position of the discontinuity detected in a wheel (11) from an average value or median for the position of the discontinuity determined from all wheels (11) of the train, or from all wheels (11) of several trains over a definable period of time.

11. Device for locating a discontinuity of a wheel-track contact along a wheel-track contact trajectory when a wheel (11) of a rail vehicle or train passes over at least one track component (1) of a railway track, in particular for carrying out a method according to one of claims 1 to 10, comprising - the at least one track component (1), at least one sensor mounted on the track component (1) or in its vicinity for detecting a sensor signal representing the temporal progression of a mechanical-dynamic stress on the track component (1) due to a wheel-track interaction in at least one spatial direction, - a signal evaluation circuit, to which the sensor signal is supplied and which preferably has stored the local distance between two reference features of the travel path arranged at a known distance from one another within the measuring range of the sensor, wherein the signal evaluation circuit is set up to evaluate the sensor signal and to detect a first and a second local extremum (A, B) which are assigned to the reference features of the travel path, and to detect a third local extremum (C) of the sensor signal which occurs at a time interval from the first and the second local extremum (A, B). which is determined as the discontinuity of the wheel-track contact, whereby the position of the discontinuity can be determined according to the time interval of the local extrema (A, B, C) and preferably based on the known local distance of the reference features.

12. Device according to claim 11, characterized in that the at least one sensor is designed as an acceleration sensor or deformation sensor.

13. Device according to claim 11 or 12, characterized in that the track component (1) is designed as a rail switch or crossing with at least one wing rail (5), at least one sleeper or solid base and a rigid or movable frog (4) and the discontinuity of the wheel-track contact is a wheel transfer area on the wing rail (5) and / or on the frog tip (7).

14. Device according to claim 13, characterized in that the reference features of the guideway component (1) are formed by a wing rail knee (12) and a cross-sectional change of the frog (4).

15. Device according to one of claims 11 to 14, characterized in that the signal evaluation circuit is designed when passing over a plurality of wheels (11) of one or more rail vehicles or trains in order to detect the sensor signal for at least a subset of the wheels (11) or for each wheel (11) and to evaluate it to determine the position of the discontinuity and to use an evaluation of positions of the discontinuity to determine a probable position close and issue a warning signal preferably when a certain probable situation is reached.

16. Device according to claim 15, characterized in that the evaluation comprises the formation of a moving average of the discontinuity positions over a predetermined period of time or a predetermined number of passes, wherein in the case of a shift or shift rate of a predetermined extent of the moving average, a geometric or temporal limit value of the wear condition is inferred and a warning signal is issued.

17. Device according to one of claims 11 to 16, characterized in that the signal evaluation circuit is designed to detect the sensor signal when each wheel (11) involved of the rail vehicle or train passes over it and to evaluate it to determine the position of the discontinuity and to conclude a state of wear of this wheel (11) from a deviation of a predetermined extent of the position of the discontinuity detected at a wheel (11) from an average value or median for the position of the discontinuity determined from all wheels (11) of the train, or from all wheels (11) of several trains over a definable period of time.

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