Fibre-optic monitoring device for monitoring adhesion conditions, and corresponding fibre-optic monitoring system and method

Abstract

The present invention relates to a fibre-optic monitoring device (30) for monitoring adhesion conditions between at least one wheel (12) of a rail vehicle unit (11) of a rail vehicle (10) and a rail (20) on which the rail vehicle unit (11) travels, the fibre-optic monitoring device comprising: at least one optical fibre (31) which extends at least along a section of the rail (20) in a direction of travel (x); at least one light-coupling unit (32) which is designed to couple light into the at least one optical fibre (31); and at least one detection unit (32) which is optically connected to the at least one optical fibre (31), wherein the at least one optical fibre (31) is designed to change a property of light guided through the optical fibre (31) depending on vibrations acting on the optical fibre (31), and wherein the at least one detection unit (32) is designed to detect the changed property of the light.

Description

[0001] 2024PF00219 October 29, 2024

[0002] 1

[0003] DESCRIPTION

[0004] Fiber optic monitoring device for monitoring adhesion conditions, as well as corresponding fiber optic monitoring system and method

[0005] The present invention relates to a fiber optic monitoring device for monitoring adhesion conditions between a wheel of a rail vehicle unit of a rail vehicle and a rail traversed by the rail vehicle unit, a fiber optic monitoring system with such a fiber optic monitoring device, and a method for monitoring adhesion conditions between at least one wheel of a rail vehicle unit of a rail vehicle and a rail traversed by the rail vehicle unit.

[0006] During propulsion and braking operations in rail vehicles, it is generally assumed that target adhesion conditions exist between the respective wheels and the rail being traveled on, towards which the propulsion and / or braking systems can be controlled. However, these adhesion conditions, which can be represented, for example, by a coefficient of friction, can deviate from the assumed adhesion conditions during actual ferry operation for various reasons. Such deviations can be attributed, for example, to weather conditions such as rain and snow, the condition of the wheels, and / or the condition of the rail, and alter the maximum available adhesion and thus the ability to transmit propulsion or braking forces between the wheel and the rail.

[0007] To account for potentially different actual liability conditions compared to theoretical ones and to adjust the drive and / or brake control accordingly, liability conditions can be determined or estimated based on sensors installed on the rail vehicle. These sensors, for example, detect wheel speed to determine slippage, among other things. However, the placement of such sensors can be challenging. 2024PF00219

[0008] 2. Due to space constraints, this may be impossible or at least difficult. Furthermore, every rail vehicle unit, especially every wheel, must be equipped with such sensors for comprehensive monitoring to enable local surveillance. Because of their direct proximity to the wheel, the sensors are also exposed to external influences that can negatively affect reliable detection or against which the sensor must be protected at considerable expense.

[0009] The object of the present invention is to provide an improved means for monitoring adhesion conditions between at least one wheel of a rail vehicle unit and a rail traversed by the rail vehicle unit.

[0010] The problem is solved by the subject matter of the independent claims. Advantageous further developments are the subject matter of the dependent claims.

[0011] According to the invention, a fiber optic monitoring device is provided for monitoring adhesion conditions between at least one wheel of a rail vehicle unit and a rail traversed by the rail vehicle unit. The fiber optic monitoring device comprises at least one optical fiber running along at least a section of the rail in one direction of travel, at least one light coupling unit configured to couple light into the at least one optical fiber, and at least one detection unit optically connected to the at least one optical fiber. The at least one optical fiber is configured to change a property of light guided through the optical fiber depending on a vibration acting on the optical fiber, and the at least one detection unit is configured to detect the changed property of the light.

[0012] In this context, a rail vehicle is understood to be a vehicle consisting of one or more rail vehicle units. A rail vehicle unit can be, for example, a locomotive or a wagon. In the case of only one rail vehicle unit, the rail vehicle unit corresponds to 2024PF00219.

[0013] 3

[0014] Rail vehicle. When several rail vehicle units are coupled together, the rail vehicle is formed from these multiple units, and this can also be referred to as a rail vehicle train or train consist. Each rail vehicle unit has several wheels that allow it to move along a rail.

[0015] Monitoring the adhesion conditions between at least one wheel of the rail vehicle unit and the rail is based on the detection of vibrations caused by the wheel traversing the rail. These vibrations represent the adhesion conditions, allowing for the determination or estimation of an adhesion value that reflects the current conditions. This adhesion value can be a coefficient of adhesion or friction, or a comparative value that can be expressed as an absolute or relative figure compared to a target value or other predetermined values.

[0016] Fundamentally, mechanical vibrations are generated by the contact between the wheel and the rail during travel. These vibrations are transmitted to the rail, the track bed, and the surrounding environment. If the adhesion conditions on the rail deteriorate, for example due to moisture or contamination, the available adhesion—that is, the maximum transmissible tangential force in the contact between wheel and rail—also decreases. This results in high relative speeds in the frictional contact between wheel and rail, particularly during acceleration and braking. This so-called macroscopic slip influences the mechanical vibrations caused by the wheel-rail contact, which can be detected. Changes in the detected signals can be compared with predetermined adhesion conditions to draw conclusions about current adhesion conditions.

[0017] When the adhesion conditions change, or when switching from rolling conditions to macroscopic slippage, the detected signals change in frequency and amplitude. By comparing this to a corresponding signal pattern 2024PF00219

[0018] 4. Using previously determined pattern assignments, the type and significance of the limited liability condition can be classified. Alternatively or additionally, AI-based pattern recognition and classification can also be performed.

[0019] For example, if rolling conditions for the wheels are without macro-slip, a broadly distributed frequency spectrum is to be expected. Wheel damage in this case follows an integer frequency spectrum due to the rolling conditions. If macroscopic slip occurs, a reduction in the amplitude of the sidebands in the frequency spectrum is expected. The greater the reduction in amplitude from the average level, the lower the traction conditions are likely to be. Accordingly, the rail vehicle can react to the deteriorated traction conditions and / or transmit a warning to following rail vehicles.

[0020] To detect vibrations, a fiber optic monitoring device is used, which enables, in particular, spatially resolved, real-time detection of the vibrations. Detection occurs in or near real time. In other words, the vibrations affect the properties of the electromagnetic waves or light guided in the optical fiber. The change in the properties of the light is accompanied by a change in the guidance properties of the optical fiber.

[0021] Rail networks are already partially equipped with optical fibers. For example, optical fibers and related detection units are used to identify rail breaks or to locate rail vehicles. These optical fibers, or optical fibers yet to be laid, can be used to detect vibrations and thus the adhesion conditions. By appropriately configuring the optical fibers with respect to changes in the properties of the light transmitted through them, and / or by appropriately configuring the detection unit to detect the changed properties of the light representing the vibrations, monitoring of the adhesion conditions can be implemented. This monitoring can be carried out continuously or according to a light pulse rate. This allows for the operation of a rail vehicle, or even several rail vehicles, to be monitored.

[0022] 5 moving vehicles are adapted to the liability conditions that can be determined via the detection unit in order to be able to operate the rail vehicle(s) adapted to the liability conditions.

[0023] Especially when dealing with multiple rail vehicles, the determined liability conditions in relation to a preceding rail vehicle can be used to proactively adjust the operating conditions or the control of following rail vehicles. This adjustment can relate to the liability conditions and / or the operation of the preceding rail vehicle. This also enables better utilization of the rail network by multiple rail vehicles and thus an increase in rail vehicle density through the time- and location-resolved determination of liability conditions, particularly in autumn and winter, which can be associated with deteriorated liability conditions due to moisture, snow, and ice.

[0024] In one embodiment, the at least one optical fiber and the at least one detection unit form a scattering-based, in particular Rayleigh scattering-based, fiber-optic monitoring device.

[0025] In the scattering-based monitoring device, at least one detection unit is configured to detect a change in the optical path length caused by vibrations and a resulting change in the reflected intensity of successive pulses from the same area of ​​the optical fiber into which the light is coupled.

[0026] For example, the optical fiber is locally stretched by vibrations of a corresponding frequency and amplitude, which also changes the transit time of at least a portion of the light with a corresponding frequency and amplitude. This altered transit time is detected by at least one detection unit. This type of monitoring device can, for example, utilize Rayleigh scattering in the optical fiber, and the corresponding configuration of the detection unit is based on the altered pulse transit time of the light at a specific fiber impurity (2024PF00219).

[0027] 6 scattered light or light component. The change is based on the mechanical stresses caused by the vibrations, such as strains, in the structure, which alter the period of the nearby fiber impurity that causes the scattering.

[0028] In Rayleigh scattering, a coherent laser pulse is sent along an optical fiber. Imperfections within the fiber cause it to act as a distributed interferometer with a measurement length approximately equal to the length of the laser pulse. The intensity of the reflected light can then be measured as a function of time after the laser pulse transmission. This principle is also known as coherent Rayleigh optical time-domain reflectometry (COTDR).

[0029] For example, the fiber optic monitoring device utilizes so-called DAS technology (Distributed Acoustic Sensing), in which a light pulse or laser pulse introduced into the optical fiber propagates along the fiber. Light components are backscattered as Rayleigh scattering through interactions with the optical fiber at defects, inclusions, or other imperfections that deviate from an ideal structure. The Rayleigh scattering pattern detected by the detection unit is altered by vibrations and can thus be used to monitor the adhesion conditions represented by these vibrations. The location of the vibrations can be determined by timing measurements that provide information about the duration from the emission of the light pulse to the reception of the backscattered light.

[0030] In DAS technology, the optical fiber is the sensor element, and the detection unit, an optoelectronic device, measures the signals generated by the sensor element. Accordingly, acoustic frequency-strain signals can be detected over long distances and under various environmental conditions.

[0031] Scatter-based monitoring, particularly DAS technology, can enable the use of conventional fiber optic cables that are already installed for telecommunications applications or at least readily available. 2024PF00219

[0032] 7

[0033] In one embodiment, the at least one optical fiber and the at least one detection unit form a wavelength-based fiber-optic monitoring device.

[0034] In the wavelength-based monitoring device, the at least one detection unit is configured to detect a change in the wavelength of the light transmitted through the optical fiber, particularly reflected light, caused by vibrations. For example, the optical fiber is locally stretched by the vibrations with a corresponding frequency and amplitude, which also changes the wavelength of at least a portion of the light with a corresponding frequency and amplitude. This changed wavelength is detected by the at least one detection unit.

[0035] In one embodiment, the at least one optical fiber has several distributed fiber Bragg gratings along the length of the optical fiber along the rail, and the at least one detection unit is configured to detect the wavelength shift of the light reflected at the respective fiber Bragg grating.

[0036] This type of wavelength-based monitoring device, utilizing fiber Bragg gratings within the optical fiber and a correspondingly configured detection unit, relies on the changing wavelength of the light, or the portion of light, reflected by the respective fiber Bragg grating. This wavelength change is caused by mechanical stresses in the structure due to vibrations, such as strains, which alter the period of the nearby fiber Bragg grating and thus the wavelength it reflects. The spatial resolution can be determined by the duration of the transmitted pulse. For example, a 100 ns pulse can be used with a resolution of 10 m.

[0037] In one embodiment, the at least one optical fiber and the at least one detection unit form a phase-based fiber-optic monitoring device. 2024PF00219

[0038] 8

[0039] Alternatively or additionally to detecting a change in wavelength, vibrations can also be monitored or determined by detecting a phase shift of the light guided in the optical fiber or a corresponding component of the light. The fiber optic monitoring device can, with respect to a combination of wavelength-based and phase-based monitoring, have at least two optical fibers and / or two optical detection units, each directed towards either wavelength-based or phase-based monitoring. The optical fiber and / or the detection unit can also be configured such that, with respect to the optical fiber, changes in both wavelength and phase are induced by corresponding vibrations, and with respect to the detection unit, both changed wavelengths and a phase shift can be detected.

[0040] In one embodiment, the at least one optical fiber is configured as a fiber-optic interferometer, in particular as a Fabry-Perot interferometer, and the at least one detection unit is configured to detect the phase shift of the light reflected in the optical fiber.

[0041] For example, vibrations can cause changes in the optical path length within the optical fiber, which in a Fabry-Perot interferometer alters an interference fringe pattern, which in turn can be detected by the detection unit.

[0042] In one embodiment, the optical fiber is configured to be arranged, at least section by section, in the rail, on the rail and / or in a rail bed at a predetermined distance from the rail, in particular below and / or to the side of the rail.

[0043] Since vibrations from the contact between the wheel and the rail are transmitted to the rail and the track bed during ferry operation, the optical fiber can be laid, at least in sections, in and / or on the rail and / or in the track bed. Therefore, the optical fiber can have a configuration that allows for such installation. For example, the optical fiber with a 2024PF00219

[0044] 9

[0045] A protective sheath, either flexible or rigid, protects the optical fiber from external influences such as moisture, high and / or low temperatures, damage from rodents, and the like when it is laid in the track bed. The optical fiber may also have appropriate fastening devices to facilitate its installation. Laying the optical fiber in or on the rail and / or in the track bed thus refers to a fiber-optic monitoring device located along the track.

[0046] Laying in the rail bed below the rail and / or to the side of it refers to a laying that has a predetermined distance of the optical fiber in the direction of gravity, i.e. below the rail, and / or a predetermined distance parallel to the rail with an offset in a ground plane, i.e. to the side of the rail.

[0047] Routing the optical fiber along and / or within the rail simplifies adherence to a predetermined fiber path in relation to the rail. Routing within the rail bed can provide better protection for the optical fiber.

[0048] Alternatively, the optical fiber can also be provided in the rail vehicle unit, thereby forming a rail vehicle-side fiber optic monitoring device.

[0049] In one embodiment, the at least one detection unit includes at least one light coupling unit.

[0050] The fiber optic monitoring device can therefore have a compact design and introduce light or light pulses tailored to the detection principle into the optical fiber.

[0051] In another aspect, the present invention relates to a fiber optic monitoring system for monitoring adhesion conditions between at least one wheel of a rail vehicle unit and a [unclear] from 2024PF00219

[0052] 10

[0053] The fiber optic monitoring system comprises at least one fiber optic monitoring device as described above and at least one adhesion condition determination unit configured to determine an adhesion value between the at least one wheel and the rail based on the data detected by the at least one detection unit.

[0054] The liability condition determination unit thus converts a light property detected by the detection unit into a liability value that can represent the liability conditions with temporal and spatial resolution. The liability value can be a concrete or quantified value, such as a coefficient of friction, or it can qualitatively represent a liability condition. A qualitative liability value can, for example, refer to a change in the detected light properties, which, if a predetermined limit is exceeded or fallen below, allows a statement to be made about whether the liability conditions are sufficient or insufficient during operation.

[0055] The liability condition determination unit can be configured to display the specified liability value or a liability value trend in relation to the route traveled, i.e., position-specifically or with location resolution, and / or to transmit such results to a higher-level unit. This can be done through continuous or demand-based display and / or signal transmission. Demand-based display and / or signal transmission can, for example, mean that the display and / or signal transmission only occurs when the liability conditions deteriorate according to predetermined liability conditions to such an extent that action and / or at least information is required.

[0056] In one embodiment, the fiber-optic monitoring system includes at least one data processing unit configured to process the data detected by the at least one detection unit and to forward the processed data to the at least one liability condition determination unit. 2024PF00219

[0057] 11

[0058] The data processing unit can, for example, include a filter unit to process the data transmitted by the detection unit as filtered data. Furthermore, the data processing unit can convert the detected changes in light properties into vibrations and / or perform real-time analysis. Finally, the functionalities of the data processing unit can also be integrated into the liability condition determination unit.

[0059] In one embodiment, the fiber optic monitoring system includes a control device, wherein the at least one liability condition determination unit is configured to transmit the determined liability value to the control device, and the control device is configured to receive the determined liability value and compare it with at least one predetermined liability value.

[0060] The control device can, for example, include a memory that compares the predetermined liability value with the liability value transmitted by the liability condition determination unit. Alternatively, the predetermined liability value can be derived by the control device as the minimum liability value required according to the current operating conditions, or it can be specified by a higher-level control unit. Furthermore, the control device can also include the liability condition determination unit itself or integrate the functionalities of the liability condition determination unit.

[0061] The control device can be configured to adjust the operating parameters or the control of an operating process, such as an acceleration or braking process, to the transmitted, i.e., current, liability value. Particularly when the current liability value deviates from the predetermined liability value by a predetermined amount, or especially when it falls below the predetermined liability value by a predetermined amount, the control device can adjust control parameters to accommodate the changed liability conditions. 2024PF00219

[0062] 12

[0063] In one embodiment, the control device is at least a control device of a rail vehicle.

[0064] The control device of the rail vehicle can therefore directly influence the control of components dependent on liability conditions.

[0065] Alternatively or additionally, the control device can also be a trackside control device that can, for example, centrally transmit control commands to individual rail vehicles and / or rail vehicle units. This could be, for example, an internet- or cloud-based control center that can communicate remotely with the rail vehicle and / or rail vehicle unit or the control device of the rail vehicle and / or rail vehicle unit.

[0066] In one embodiment, the control device is configured to control at least one brake unit of a rail vehicle or the rail vehicle described above, depending on the specific adhesion value.

[0067] Accordingly, the control device can, for example, provide a reduced clamping force for the corresponding brake units during braking when poor adhesion conditions are derived from the adhesion value, or initiate a wheel slip protection system to prevent the wheels from slipping on the rail. Even if the detection of deteriorated adhesion conditions on a wheel can no longer be used to intervene on the wheel itself, at least the following wheels in the direction of travel can still be controlled in light of the deteriorated adhesion conditions.

[0068] In one embodiment, at least one liability condition determination unit and / or at least one previously described data processing unit is integrated into at least one fiber optic detection unit or the previously described control device. 2024PF00219

[0069] 13

[0070] The detection unit can therefore also take over the functionalities of the liability conditions determination unit. Alternatively or additionally, the detection unit can also have the functionalities of the data processing unit.

[0071] Provided that the fiber optic monitoring device has at least one liability condition determination unit, the fiber optic monitoring device can also directly form the fiber optic system.

[0072] The features described above for the fiber optic monitoring system are equally applicable to the fiber optic monitoring system. Likewise, features described for the fiber optic monitoring system are transferable to the fiber optic monitoring device, provided they have not already been described therein.

[0073] In one embodiment, the fiber optic monitoring system has a trackside data processing unit configured to receive the specified liability values, in particular to store them and / or to transmit them directly or in further processed form to the rail vehicle following the rail vehicle.

[0074] Accordingly, the trackside data processing unit can be used to diagnose restricted rail conditions with regard to insufficient adhesion. To identify randomly or uniquely detected insufficient adhesion conditions that cannot be attributed to the rail condition itself, but rather to, for example, a short-term disruption or error-based detection, multiple adhesion values ​​for the same location can be stored and compared. From this, a corresponding confidence level can be generated through repeated detection of the adhesion conditions at a location, which can relate to both current adhesion conditions and changes in the adhesion conditions. The adhesion conditions can then be used by the 2024PF00219

[0075] 14. Data will be transmitted to the following rail vehicles, which have not yet reached the position attributable to the specific liability conditions, via the trackside data processing unit in order to be able to react to it.

[0076] In a further aspect, the present invention relates to a method for monitoring adhesion conditions between at least one wheel of a rail vehicle unit and a rail traversed by the rail vehicle unit. The method comprises the following steps:

[0077] Step 1: Detecting vibrations using a previously described fiber optic monitoring device, and

[0078] Step 2: Determining a coefficient of adhesion between at least one wheel and the rail based on the detected vibrations.

[0079] Based on the functionalities of the fiber optic monitoring device described above, the method provides for the detection of vibrations by using at least one optical fiber and a corresponding detection unit, whereby the determination of the adhesion value between at least one wheel and the rail is based on the detected vibrations.

[0080] The detection unit can detect the vibrations directly, i.e., directly convert the signals of the property changes of the light into vibration signals, or indirectly by detecting the property changes of the light, which are then only converted into vibrations by the previously described data processing unit or the previously described liability condition determination unit.

[0081] In one embodiment, the procedure includes a further step 3 of controlling at least one brake unit of the rail vehicle based on the determined liability value and / or the transmission of liability values ​​or processed liability values ​​to the following rail vehicles.

[0082] The control of at least one brake unit of the rail vehicle can be continuous or dependent on the adhesion value determined from the vibrations 2024PF00219

[0083] 15. If, for example, a control device for a brake unit provides control parameters that depend on the adhesion value, these can be continuously adjusted as a function of the currently determined adhesion value. However, as mentioned at the beginning, the control can also be initiated only when a predetermined adhesion value is reached by the currently determined adhesion value, in order to avoid excessively frequent changes in the control parameters and to protect the controlled component. The adjustment of the control according to the attainment of the predetermined adhesion value can also be linked to a time criterion to avoid excessively frequent or unnecessary control adjustments. Accordingly, an adjustment by the control device is only initiated when the predetermined adhesion value has been reached for a predetermined period or with a predetermined frequency within a predetermined period.

[0084] The control can refer to the wheel that triggers the detection, or alternatively or additionally, in particular to the control of subsequent wheels.

[0085] Alternatively or additionally, step 3 can also be aimed at diagnosing restricted rail conditions. For this purpose, the specific adhesion conditions can be transmitted from a trackside data processing unit either directly to a following rail vehicle or further processed before transmission. This further processing could, for example, involve storing and comparing several adhesion values ​​detected at a single location, whereby, for instance, a confidence level regarding specific adhesion values ​​is determined by the frequency of those values ​​for a given location within a predetermined period.

[0086] Features described above for the fiber optic monitoring device and / or fiber optic monitoring system are equally applicable to the process as process features. Likewise, features described for the process relating to the fiber optic monitoring device and / or fiber optic monitoring system are applicable to the fiber optic device 2024PF00219.

[0087] 16

[0088] Monitoring device and / or fiber optic monitoring system transferable, unless they have already been described here.

[0089] Exemplary embodiments of the present invention are described below with reference to the accompanying drawings.

[0090] In detail, it shows

[0091] Fig. 1 shows an exemplary embodiment of a fiber optic monitoring system with a fiber optic monitoring device for monitoring adhesion conditions between at least one wheel of a rail vehicle unit of a rail vehicle and a rail traversed by the rail vehicle;

[0092] Fig. 2 shows a schematic representation of an exemplary configuration of the fiber optic monitoring system for determining a liability value;

[0093] Fig. 3 shows an exemplary position-related progression of a liability value; and

[0094] Fig. 4 shows an embodiment of a method for monitoring liability conditions.

[0095] Fig. 1 shows an exemplary embodiment of a fiber optic monitoring system 100 with a fiber optic monitoring device 30 for monitoring adhesion conditions between at least one wheel 12 of a rail vehicle unit 11 of a rail vehicle 10 and a rail 20 traversed by the rail vehicle 11.

[0096] In the exemplary embodiment, the rail vehicle 10 is formed by the rail vehicle unit 11, but in alternative embodiments it can also comprise several rail vehicle units. The rail vehicle unit 11 moves along the rail 20 in a direction of travel x and has, with respect to the direction of travel x, a front set of wheels 12 and a rear set of 2024PF00219

[0097] 17

[0098] The front and rear sets of wheels 12 each comprise two wheels 12 per side of the rail vehicle unit 11, i.e., four wheels 12 per set and thus eight wheels 12 per rail vehicle unit 11. In alternative embodiments, either only one wheel per side of the rail vehicle unit and set or more than two wheels per side of the rail vehicle unit and set may be provided. The wheels 12 of each set are braked by a brake unit 13 assigned to the respective set, which is controlled by a control device 14 of the rail vehicle unit 11.

[0099] To monitor the adhesion conditions between the wheels 12 of the front and rear sets of one side of the rail vehicle unit 11, the fiber optic monitoring system 100 has a fiber optic monitoring device.

[0100] 30. It is assumed here that the liability conditions on one side of the rail vehicle unit 11 are essentially analogous to those on the other side of the rail vehicle unit 11. In alternative embodiments, however, two fiber optic monitoring devices may also be provided, with one fiber optic monitoring device relating to one side of the rail vehicle unit and the other fiber optic monitoring device relating to the other side of the rail vehicle unit. In such a case, the fiber optic monitoring devices or the respective optical fibers must be spaced sufficiently far from the side of the vehicle unit not assigned to them that the detection via the respective fiber optic monitoring device is not influenced in a non-extractable way by the side of the rail vehicle unit not assigned to it.

[0101] The fiber optic monitoring device 30 shown here has an optical fiber

[0102] 31, which is laid in the track bed along the direction of extension of the rail 20. Specifically, the optical fiber 31 is positioned below the rail 20 and laterally outwards, i.e., in a ground plane perpendicular to gravity, on one side of the rail vehicle unit 11. The optical fiber 31 is configured such that the vibrations caused by the two wheels of each set assigned to one side of the rail vehicle unit 11 are transmitted to contact 2024PF00219

[0103] 18 caused by the rail, which alter the properties of light guided through the optical fiber 31. The vibrations per set of wheels 12 of one side of the rail vehicle unit are schematically represented in Fig. 1 by the wavefronts propagating from the rail 20 towards the optical fiber 31.

[0104] The fiber optic monitoring device 30 also includes a detection unit 32, which is optically connected to the optical fiber 31 to detect a property of the light guided by the optical fiber 31. The detected property of the light, or the change in a corresponding property, is caused by the vibrations between the wheels 12 of a set per side in contact with the rail 20. In the present embodiment, the detection of vibrations and the related derivation of adhesion conditions are based on DAS technology, in which the optical fiber 31 is a conventional fiber optic cable and the detection unit 32 detects Rayleigh scattering as a component of light backscattered at defects in the optical fiber 31, or recognizes pattern changes.In alternative embodiments, the change in the properties of the light can be based on a change in the wavelength of a light component reflected by a fiber Bragg grating. For position assignment and thus spatially resolved detection of the wavelength change and therefore the corresponding vibrations, the optical fiber 31 in the alternative embodiment has fiber Bragg gratings uniformly distributed along its length, with each fiber Bragg grating corresponding to a specific position along the fiber. Vibrations caused at the respective position along the rail 20 by the contact between the wheels 12 of a set of wheels on one side of a rail vehicle and the rail change the current structure of the respective fiber Bragg grating and thus the wavelength of the light component reflected by the fiber Bragg grating.The detection unit then assigns a reflected light component with a correspondingly changed wavelength to the position of the fiber Bragg grating, so that the vibrations causing the wavelength change can be derived from this.

[0105] To introduce the light to be guided in the optical fiber 31, the

[0106] Detection unit 32 includes a light coupling unit 33. The light coupling unit 2024PF00219

[0107] 19

[0108] In the present embodiment, 33 is configured to emit light pulses with different wavelengths and couple them into the optical fiber 31.

[0109] Fig. 2 shows a schematic representation of an exemplary configuration of the fiber optic monitoring system 100 for determining a liability value. In the present embodiment, the fiber optic monitoring system 100 thus has, in addition to the fiber optic monitoring device 30, a data processing unit 40 and a liability condition determination unit 50.

[0110] The fiber optic monitoring device transmits the properties or changes in the properties of the light detected by the detection unit 32 to the data processing unit 30, which analyzes the transmitted data in real time and determines position- and time-related vibration data. The position- and time-related vibration data is then transmitted by the data processing unit 40 to the liability condition determination unit 50, which in turn determines a position- and time-related liability value from the position- and time-related vibration data.

[0111] For example, the position- and time-related adhesion value, determined according to the vibrations measured at a specific time at the position of the wheels 12 of the front set on one side of the rail vehicle unit 11, represents deteriorated adhesion conditions due to contamination on the rail 20, compared to a predetermined adhesion value. However, since the wheels 12 of the front set have already traversed the rail 20 at the position where the wheels 12 of the rear set are located at that specific time, an adhesion value can be determined at the position of the wheels of the rear set that is essentially equivalent to the predetermined adhesion value, either due to the cleaning effect of the wheels 12 of the front set or because no contamination was present there.Under certain circumstances, a positive or negative deviation in the adhesion value can also occur for the position of wheels 12 of the rear set, which can be detected accordingly. 2024PF00219.

[0112] 20

[0113] Fig. 3 shows an exemplary position-related curve of a adhesion value. Here, the adhesion value corresponds to the maximum available adhesion for transmitting a braking force. The adhesion y, which represents the maximum available adhesion as an adhesion value, is plotted against the direction of travel x. The direction of travel x corresponds to different positions x. nalong rail 20. A minimum adhesion value ymin is also specified here, at which a predetermined braking procedure can be carried out correctly. The curve of the actual adhesion value shows that the adhesion falls below the minimum adhesion value ymin from position xi along rail 20. Position xi represents a position at which the Rayleigh scattering pattern detected by the vibrations due to poor adhesion conditions corresponds to an adhesion value that is less than ymin. The vibrations due to poor adhesion conditions thus lead to a change in the pattern of light scattered at the defects. These pattern changes are detected by the detection unit 32 with respect to position xi and transmitted to the data processing unit 40 and the adhesion condition determination unit 50, in order to then output the corresponding adhesion value.

[0114] The adhesion determination unit 50 outputs the adhesion value to the control device 40 of the rail vehicle unit 11, which then, if the minimum adhesion is undershot at position xi, adjusts the control of the brake units 13 to the adhesion conditions present at position xi. Depending on the extent to which the minimum adhesion is undershot, the control device 14 initiates a wheel slip protection control.

[0115] Fig. 4 shows an embodiment of a method for monitoring the adhesion conditions. In step S1, the vibrations transmitted to the rail 20 by the contact between the respective wheels 12 per set and side of the rail vehicle unit 11 and the rail 20, and to the optical fiber 31, are detected by the detection unit 32 based on changes in the properties of the light guided in the optical fiber 31. 2024PF00219

[0116] 21

[0117] Subsequently, in step S2, the time- and position-related adhesion value is determined based on the detected time- and position-related vibrations. The time- and position-related adhesion value corresponds to the time- and position-related changes in the properties of the light reflected by the optical fiber 31, which represent the corresponding time- and position-related vibrations.

[0118] Based on the adhesion value determined in step S2, the brake unit 13 related to the position and / or another brake unit 13 that reaches the corresponding position later and / or can compensate for a changed adhesion value in an upstream or downstream position can then be controlled according to the determined adhesion value. In the present embodiment, this is done by the control device 14 of the rail vehicle unit 11, but in other embodiments, it can also be done via a central control unit, which, for example, can also be located trackside and can transmit control signals to the control unit 14 of the rail vehicle unit 11.

[0119] The invention is not limited to the described embodiments. In particular, features described in relation to the embodiments, other described configurations and further developments of the invention can be combined with one another, provided they are not mutually exclusive.

[0120] 2024PF00219

[0121] 22

[0122] REFERENCE MARK LIST

[0123] 10 rail vehicles

[0124] 11 rail vehicle unit

[0125] 12 wheel

[0126] 13 Brake unit

[0127] 14 Control device

[0128] 20 rail

[0129] 30 fiber optic monitoring devices

[0130] 31 optical fibers

[0131] 32 Detection unit

[0132] 33 Light coupling unit

[0133] 40 Data processing unit

[0134] 50 Liability Conditions Determination Unit

[0135] 100 fiber optic surveillance systems

[0136] 51 Step 1

[0137] 52 Step 2

[0138] Step 3 x Direction of travel xi Position of insufficient adhesion y Liability ymin Minimum liability

Claims

2024PF00219 23 PATENTANSPRÜCHE 1. Fiber optic monitoring device (30) for monitoring adhesion conditions between at least one wheel (12) of a rail vehicle unit (11) of a rail vehicle (10) and a rail (20) traversed by the rail vehicle unit (11), comprising: at least one optical fiber (31) extending at least along a section of the rail (20) in a direction of travel (x), at least one light coupling unit (32) configured to couple light into the at least one optical fiber (31), and at least one detection unit (32) optically connected to the at least one optical fiber (31), wherein the at least one optical fiber (31) is configured to change a property of light guided through the optical fiber (31) depending on a vibration acting on the optical fiber (31), and wherein the at least one detection unit (32) is configured toto detect the changed property of light.

2. The fiber optic monitoring device (30) according to claim 1, wherein the at least one optical fiber (31) and the at least one detection unit (32) form a scattering-based, in particular Rayleigh scattering-based, fiber optic monitoring device (30).

3. The fiber optic monitoring device (30) according to claim 1 or 2, wherein the at least one optical fiber (31) and the at least one detection unit (32) form a wavelength-based fiber optic monitoring device (30), wherein in particular the at least one optical fiber (31) has several distributed fiber Bragg gratings along the length of the optical fiber (31) along the rail (20), and the at least one detection unit (32) is configured to detect the wavelength shift of the light reflected at the respective fiber Bragg grating. 2024PF00219 24 4. The fiber optic monitoring device (30) according to one of the preceding claims, wherein the at least one optical fiber (31) and the at least one detection unit (32) form a phase-based fiber optic monitoring device (30).

5. The fiber optic monitoring device (30) according to claim 4, wherein the at least one optical fiber (31 ) is configured as a fiber optic interferometer, in particular as a Fabry-Perot interferometer, and the at least one detection unit (32) is configured to detect the phase shift of the light reflected in the optical fiber (31 ).

6. The fiber optic monitoring device (30) according to one of the preceding claims, wherein the optical fiber (31) is configured to be arranged at least sectionally in the rail (20), on the rail (20) and / or in a rail bed at a predetermined distance from the rail (20), in particular below and / or laterally from the rail (20).

7. The fiber optic monitoring device (30) according to one of the preceding claims, wherein the at least one detection unit (32) comprises the at least one light coupling unit (33).

8. Fiber optic monitoring system (100) for monitoring adhesion conditions between at least one wheel (12) of a rail vehicle unit (11) and a rail (20) traversed by the rail vehicle unit (11), comprising: at least one fiber optic monitoring device (30) according to one of the preceding claims and at least one adhesion condition determination unit (50) configured to determine an adhesion value between the at least one wheel (12) and the rail (20) based on the data detected by the at least one detection unit (32). 2024PF00219 25 9. The fiber optic monitoring system (100) according to claim 8, wherein the fiber optic monitoring system (100) comprises at least one data processing unit (40) configured to process the data detected by the at least one detection unit (32) and to forward the processed data to the at least one liability condition determination unit (50).

10. The fiber optic monitoring system (100) according to claim 8 or 9, wherein the fiber optic monitoring system (100) comprises a control device (14), wherein the at least one liability condition determination unit (50) is configured to transmit the determined liability value to the control device (14), and the control device (14) is configured to receive the determined liability value and compare it with at least one predetermined liability value, wherein the control device (14) is in particular at least one control device of a rail vehicle (10).

11. The fiber optic monitoring system (100) according to claim 10, wherein the control device (14) is configured to control at least one brake unit (13) of a rail vehicle (10) or of the rail vehicle (10) according to claim 11 depending on the determined adhesion value.

12. The fiber optic monitoring system (100) according to any one of claims 8 to 11, wherein the at least one liability condition determination unit (50) and / or the at least one data processing unit (40) according to claim 9 is integrated into the at least one fiber optic detection unit (30) or the control device (14) according to claim 11.

13. The fiber optic monitoring system (100) according to one of claims 8 to 12, wherein the fiber optic system (100) has a trackside data processing unit configured to receive the liability values, in particular to store them and / or to transmit them directly or in further processed form to the rail vehicle (10) following the rail vehicle. 2024PF00219 26 14. Method for monitoring adhesion conditions between at least one wheel (12) of a rail vehicle unit (11) of a rail vehicle (10) and a rail (20) traversed by the rail vehicle unit (11), comprising the steps: Step 1 (S1): Detecting vibrations by means of a fiber optic monitoring device (30) according to any one of claims 1 to 7, and Step 2 (S2): Determining an adhesion value between the at least one wheel (12) and the rail (20) based on the detected vibrations.

15. The method according to claim 14, further comprising a step 3 (S3) of the Controlling at least one brake unit of the rail vehicle (10) based on the determined liability value and / or the transmission of liability values ​​or processed liability values ​​to the rail vehicle (10) following rail vehicles.

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