Method and system for monitoring a track portion

Abstract

The invention relates to a method for monitoring a track portion (2) for the presence or absence of at least part of a rail vehicle (4) moving on the rail (3a, 3b), wherein the method comprises: obtaining first measurement signals (6a) from a first sensor (8a) which is located at the start (7) of the track portion (2); obtaining second measurement signals (6b) from a second sensor (8b) which is located at the end (9) of the track portion (2); evaluating the first measurement signals (6a) and the second measurement signals (6b) to register or count incoming metal bodies and to register or count outgoing metal bodies, wherein both axles or wheels (10a, 10b, 10c, 10d) and any brakes (11a, 11b) present are detected as metal bodies; and inferring the presence or absence of the part of the rail vehicle (4) on the track portion (2) on the basis of the registering or counting.

Description

[0001] Description

[0002] Method and system for monitoring a track section

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to a method and a system for monitoring a track section for the presence or absence of at least a part of a rail vehicle moving on the track.

[0005] STATE OF THE ART

[0006] Traditionally, track sections are monitored using so-called axle counters by detecting the vehicle wheels through counting points (sensors).

[0007] However, it has been observed that conventional methods and systems for monitoring track sections do not provide reliable results in all situations and for all rolling stock configurations. This leads to miscounts, which in turn reduces the availability of track clearance detection.

[0008] It is therefore an object of the present invention to provide a method and a system for monitoring a track section, wherein the reliability of the method is increased and untimely or permanent occupancy of the track sections can be avoided. In particular, it is an object of the present invention to propose a method and a system for monitoring a track section which also delivers reliable results for rail vehicles which, in particular, also have magnetic track brakes between the wheels. This object is achieved by the subject matter of the independent claims. Advantageous embodiments are specified in the dependent claims.

[0009] SUMMARY OF THE INVENTION

[0010] According to one embodiment of the present invention, a method is provided for monitoring a track section for the presence or absence of at least a part of a rail vehicle moving on the track, the method comprising: obtaining first measurement signals from a first sensor located at the beginning of the track section; obtaining second measurement signals from a second sensor located at the end of the track section (in the case of switch or crossing sections, possibly further sensors that delimit the track section); evaluating the first measurement signals and the second measurement signals to register or count incoming metal bodies and to register or count outgoing metal bodies, wherein both axles or wheels and any brakes are detected as metal bodies; inferring the presence or absence of the part of the rail vehicle on the track section based on the registration or count.

[0011] The method can be implemented in software and hardware. The method can, for example, be performed or controlled by a system for monitoring a track section according to an embodiment of the present invention.

[0012] The monitored track section can typically be between 30 m long (possibly shorter, but the track section length should always be greater than the maximum axle spacing of a vehicle to prevent a vehicle from standing over the section) and virtually infinite. The rail vehicle can be used, for example, to transport passengers and / or goods.

[0013] Both the first sensor (sensor counting into the track section) and the second sensor (sensor counting from the track section) can be designed to detect metal masses or metal bodies located above or below the top edge of the rail or within the sensor's detection range. The sensors can comprise conventional sensors, particularly axle counting sensors. The sensors must also be capable of detecting the direction of travel.

[0014] For monitoring sidings, a single sensor may be sufficient to detect both entering and exiting vehicles. In this case, the first sensor is identical to the second sensor.

[0015] In other embodiments, more than two sensors may be present at different locations along the track section, and their measurements may be used.

[0016] The rail vehicle can move in the direction from the beginning of the track section to the end of the track section. The rail vehicle does not necessarily have to pass through the entire track section, but can, for example, come to a standstill before the track section has been completely traveled through or, if necessary, change direction of travel within the track section. According to other embodiments of the present invention, the rail vehicle can pass through the track section completely, so that both the first sensor and a second sensor (and / or further sensors, e.g. at a switch or crossing point) are passed by the rail vehicle or part of the rail vehicle at the same time. The rail vehicle can, for example, have a length of between 10 m and 500 m.Embodiments of the present invention may also make it possible to detect the presence or absence of a complete rail vehicle on the track section.

[0017] The measurement signals can be received from the first sensor or the second sensor via cable connections, optical connections, or wirelessly. The measurement signals can include analog measurement signals, for example, values ​​of induced voltages generated in the sensors due to passing metal objects.

[0018] The evaluation of the first measurement signals and the second measurement signals can, for example, comprise a comparison with one or more threshold values.

[0019] Incoming metal bodies can be understood as metallic, particularly ferromagnetic masses or bodies that are parts of the rail vehicle and that move past the first sensor into the track section. Exiting metal bodies can be understood as all metallic, particularly ferromagnetic parts of the rail vehicle that move past the second sensor and thus move outside the track section.

[0020] Conventionally, only the wheels of rail vehicles were registered. However, according to the present embodiment of the invention, any brakes present are also detected, which can be provided in particular between two wheels or between two axles of the rail vehicle. The brakes can be used for braking in certain driving situations or under certain external environmental conditions.

[0021] Embodiments of the present invention do not necessarily require knowledge of the presence of such brakes on the rail vehicle. However, the evaluation can be carried out in such a way that any brakes present are also detected without requiring knowledge of their presence.

[0022] According to one embodiment of the present invention, at least one counter (or register or memory location) can be provided that, for example, increments the number of metal bodies entering and decrements the number of metal bodies exiting. Thus, neither the number of incoming metal bodies nor the number of outgoing metal bodies necessarily need to be counted. At the end of an evaluation or measurement period, only the reading of the at least one counter can be read to determine whether the part of the rail vehicle is present or missing in the track section.

[0023] According to another embodiment, both the number of times the metal body leaves and the number of times the metal body enters can actually be counted, in particular in two different counters (or registers or memory locations). The evaluation (generation of a clearance signal) occurs after comparing the counter readings of the sensor counting in and out. If the comparison results in the same number of metal bodies being counted in and out, the rail vehicle has left the track section. With active magnetic rail brakes, the saturation of the rail is detected instead of the metal body.

[0024] Embodiments of the present invention do not require knowledge of the number of axles or wheels and / or the number of any brakes present on the rail vehicle. Thus, differently configured rail vehicles can be supported by embodiments of the present invention in that their absence or presence can be reliably determined. According to one embodiment of the present invention, the method is designed such that the metal bodies comprise elements of the rail vehicle that are arranged vertically close to the rail, in particular wheels and / or wheel axles and / or brakes of the rail vehicle.

[0025] The method can thus detect both the wheels and wheel axles of the rail vehicle, as well as the brakes, both when entering and exiting the monitored track section. The method is therefore applicable to various types of rail vehicles.

[0026] According to one embodiment of the present invention, the method is designed such that the evaluation of the first measurement signals and the second measurement signals comprises: determining a first number of first measurement signals which are above an upper threshold or which are below a lower threshold; determining a second number of second measurement signals which are above the upper threshold or which are below the lower threshold, wherein the upper threshold is greater than the lower threshold.

[0027] The measurement signals can, for example, be given as a measurement signal level, in particular relative voltage (for example related to a measurement value in the absence of a metal body or rail vehicle) as a function of time. The upper threshold and / or the lower threshold can be determined by determining measurement values ​​from known metal bodies or from vehicles of known configuration or training data, wherein, for example, test measurements can be carried out with different rail vehicles passing the sensors. For the test measurements, the configuration of the rail vehicles with regard to the number of wheels and / or any brakes present can be known. The method can therefore be carried out by defining only an upper threshold and a lower threshold and determining whether the respective measurement signals lie above or below the respective threshold.This provides a very simple method for reliable monitoring of the track section.

[0028] According to one embodiment of the present invention, a conventionally provided delay in the measurement signals below the lower threshold is suppressed. Conventionally, a lower threshold can be used to detect a fault during assembly of the respective sensor, in particular to detect whether fixing bolts or screws have come loose, so that the position of the sensor relative to the rail has changed unfavorably, e.g. the sensor has fallen off the rail. For this purpose, a measurement signal below the lower threshold was conventionally suppressed or delayed. This conventionally provided delay is suppressed according to embodiments of the present invention, since the event that a measurement signal lies below the lower threshold is also used to detect metal bodies, in particular to detect a magnetic rail brake, in a reliable manner.

[0029] According to one embodiment of the present invention, the method is designed such that the inference as to the presence or absence of the rail vehicle comprises: comparing the first number with the second number; inferring the presence or absence of the part of the rail vehicle on the track section from the comparison result.

[0030] By comparing the first number with the second number, it can be determined, for example, whether the number of metal bodies entering the track section is the same as or different from the number of metal bodies leaving the track section. This allows for reliable monitoring.

[0031] According to one embodiment of the present invention, the method further comprises: concluding that the track section is free of the part of the rail vehicle if the first number is equal to the second number; and / or concluding that the track section is not free of the part of the rail vehicle if the first number is greater than the second number; and / or concluding that an error is present if the first number is less than the second number.

[0032] This means that simple logical queries are sufficient to achieve a reliable diagnosis of the occupancy status of the track section.

[0033] According to one embodiment of the present invention, the method is designed such that the upper threshold is selected such that a measurement signal produced by a non-activated brake, in particular a magnetic rail brake, of the rail vehicle or by a wheel axle or wheel is above it.

[0034] This means that by determining that a measurement signal is above the upper threshold, both a wheel or a wheel axle and a non-activated brake can be reliably detected.

[0035] According to one embodiment of the present invention, the method is designed such that the lower threshold is selected such that a measurement signal caused by an activated brake, in particular a magnetic rail brake, of the rail vehicle is below and a measurement signal caused by a wheel or a wheel axle is above.

[0036] Thus, by determining whether a measurement signal is below the lower threshold, an activated brake can also be detected. This makes it possible to reliably detect or record both an activated brake and a deactivated brake by evaluating the respective measurement signals. This improves the reliability of the process.

[0037] According to one embodiment of the present invention, the method is designed such that the upper sleeper and / or the lower sleeper are adjusted such that both wheel axles and / or wheels and any magnetic rail brakes present are counted or registered both in the activated and in the inactivated state, wherein a rail friction contact surface of the magnetic rail brake (in the non-activated state) has a distance of 4 mm to 9 mm from the rail.

[0038] A magnetic rail brake can be provided, for example, between two wheel axles or wheels of the rail vehicle, for example in a railcar. For braking, the magnetic rail brake can be brought into contact with the surface of the rail via a rail friction contact surface in order to achieve a braking effect due to frictional resistance. Embodiments of the present invention can support magnetic rail brakes that have a relatively short distance from the rail. This can be the case in particular with local rail vehicles, such as subways, commuter trains, or trams.

[0039] According to one embodiment of the present invention, the part of the rail vehicle comprises at least one magnetic rail brake, which is in particular temporarily activated or temporarily inactivated (while the measurement signals are being recorded, for example).

[0040] Traditionally, the presence of magnetic track brakes can lead to incorrect counts and thus to misdiagnosis of the occupancy of a track section. However, since magnetic track brakes can be reliably recorded and counted, rail vehicles with at least one magnetic track brake are also supported.

[0041] According to one embodiment of the present invention, the method is designed such that the first measurement signals were recorded continuously while the part of the rail vehicle passes / passes over the first sensor; wherein the second measurement signals were also recorded continuously while the part of the rail vehicle passes / passes over the first sensor.

[0042] The measurement signals can be monitored continuously, but can also be event-driven. A permanent evaluation is performed, or if there is no change in the measured values ​​recorded by the sensors within a certain period of time. The occupancy status of the track section is then derived from this.

[0043] According to one embodiment of the present invention, the first sensor and / or the second sensor is configured as a metal sensor, in particular as a counting point of an axle counter system. This allows conventional sensors to be supported, which can simplify the implementation of the invention.

[0044] According to one embodiment of the present invention, the first sensor and / or the second sensor comprises: an electromagnetic generator coil, mounted on one side of a rail of the track, for generating an alternating magnetic field; an electromagnetic detection coil, mounted on the other side of the rail of the track, for detecting an alternating magnetic field by inducing a voltage that represents, in particular, the measurement signals. The generator coil can, for example, generate a (high-frequency) alternating magnetic field with a frequency of a few kilohertz (e.g., between 30 kHz and 1000 kHz). The alternating magnetic field generated by the generator coil can also extend into the range of the detection coil.If a metal body, in particular a ferromagnetic metal body, enters the space between the generating coil and the detecting coil (for example a wheel or a magnetic rail brake of a rail vehicle), the magnetic field generated by the generating coil can be changed. This means that the voltage induced in the receiving coil, which is induced in the detecting coil due to the changed magnetic field, can be changed compared to a voltage induced in the absence of the metal body. The measuring signal can, for example, represent the level of the induced voltage, in particular related to an induced voltage (e.g. ratio) in the absence of any metal body between the exciting coil and the detecting coil, that is to say in the absence of any metal body moving on the surface of the rail.

[0045] According to one embodiment of the present invention, the rail vehicle is a long-distance rail vehicle or a local rail vehicle, in particular a subway, a tram or a suburban train.

[0046] It should be understood that features which have been explained, provided or applied individually or in any combination in connection with a method for monitoring a track section can also be applied individually or in any combination to a system for monitoring a track section according to embodiments of the present invention or vice versa.

[0047] According to one embodiment of the present invention, a system is provided for monitoring a track section for the presence or absence of at least part of a rail vehicle moving on the track, the system comprising: an input port configured to receive first measurement signals from a first sensor located at the beginning of the track section; to receive second measurement signals from a second sensor located at the end of the track section; an evaluation block configured to evaluate the first measurement signals and the second measurement signals in such a way as to register or count incoming metal bodies and to register or count outgoing metal bodies, wherein both axles or wheels and any brakes present are detected as metal bodies;and to infer the presence or absence of the part of the railway vehicle on the track section based on the registration or counting;

[0048] Embodiments of the present invention will now be explained with reference to the accompanying drawings. The invention is not limited to the illustrated or described embodiments.

[0049] BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Fig. 1 schematically illustrates a system for monitoring a track section according to an embodiment of the present invention;

[0051] Fig. 2 illustrates in a schematic side view a part of a rail vehicle whose presence on a track section is monitored according to an embodiment of the present invention;

[0052] Fig. 3 illustrates measurement signals and counting pulses according to a conventional method; Fig. 4 illustrates measurement signals and corresponding counting pulses which are recorded and evaluated according to embodiments of the present invention;

[0053] Fig. 5 shows experimental results obtained according to embodiments of the present invention.

[0054] DETAILED DESCRIPTION OF EMBODIMENTS

[0055] The system 1 of Fig. 1 for monitoring a track section 2 for the presence or absence of at least a part of a rail vehicle 4 moving on the rails 3a, 3b of the track 40 has an input port 5a, 5b to receive first measurement signals 6a from a first sensor 8a located at the beginning 7 of the track section 2, and to receive second measurement signals 6b from a second sensor 8b located at the end 9 of the track section 2. The system 1 further comprises an evaluation block which is configured to evaluate the first measurement signals 6a and the second measurement signals 6b in such a way as to register or count incoming metal bodies 10a, 10b, 10c, 10d and 11a, 11b of the rail vehicle 4, wherein both axles or wheels 10a, 10b, 10c, 10d as well as any brakes 11a, 11b which may be present are detected as metal bodies.The evaluation block of the system 1 is further configured to infer the presence or absence of the part of the rail vehicle 4 on the track section 2 based on the registration or counting. The system 1 is designed to perform or control a method for monitoring the track section 2.

[0056] The rail vehicle 4 moves on the two rails 3a, 3b of a track 40 in the direction indicated by the arrow 12. In the illustrated embodiment of Fig. 1, the rail vehicle 4 comprises at least one railcar having two pairs of wheel axles 10a, 10b, 10c, 10d, with a magnetic rail brake 11a, 11b being mounted between each pair of wheel axles 10a, 10b or 10c, 10d.

[0057] The two rails 3a, 3b together with sleepers (not shown) and ballast or solid track form the track 40 .

[0058] The sensors 8a, 8b each comprise, for example, a generating coil 13 which is mounted on one side of a rail 3b of the track and is designed to generate an alternating magnetic field. The sensors 8a, 8b further comprise an electromagnetic detection coil 14 which is designed to detect an alternating magnetic field by inducing a voltage. The measurement signals 6a, 6b can in particular represent a relative (or absolute) induced voltage which is given as a proportion of an induced voltage which is generated when no metal body passes the respective sensor 8a, 8b. The sensors 8a, 8b are thus configured as metal sensors, which can also be conventionally referred to as counting points.

[0059] The system 1 may further comprise the first sensor 8a and the second sensor 8b.

[0060] In Fig. 1, the rail vehicle 4 is illustrated at a time after the wheel axles 10c, 10d and the magnetic rail brake 11b have already passed the first sensor 8a. Subsequently, the rail vehicle 4, or rather the wheels or wheel axles 10a, 10b and the magnetic rail brake 11a, also pass the first sensor 8a. During a later, second period, the rail vehicle 4, and in particular also the respective wheel axles and the magnetic rail brakes, can pass the second sensor 8b.

[0061] Fig. 2 illustrates, in a schematic side view, part of the rail vehicle 4, which moves on the rail 3a, 3b. The rail vehicle 4 comprises a wheel 10a with a wheel axle, a wheel 10b, and a magnetic rail brake 11a, which is arranged between the wheels or wheel axles 10a and 10b. The wheels 10a, 10b are mounted together with the magnetic rail brake 11a on a bogie 12a. The distance d of a rail friction contact surface 41 of the magnetic rail brake 11a from the surface of the rail 3b, which is designated by d, can be, for example, 4 to 9 mm.

[0062] Fig. 3 illustrates, in two coordinate systems, with a respective abscissa 15 indicating time, and a respective ordinate 16 indicating the relative induced voltage in the detection coil 14, which represents the measurement signal of a sensor, or indicates the digitized wheel pulse on an ordinate 17, the analog measurement signals 18, 19, which were recorded using a conventional method and which were each converted into pulses or pulse profiles 20, 21. In this case, it was only determined whether the respective measurement signal 18, 19 lies above a conventional upper switching threshold 22 or not. If the measurement signal 18, 19 lies above the conventional upper switching threshold, which is e.g. 1.58, the signal is evaluated as a counting pulse 20, 21 and thus counted as a wheel or as a wheel axle of the rail vehicle. A lower conventional switching threshold 22a (e.g. at 0.85) is used for drop detection.

[0063] In areas 23, 24, 25, 26 there are actually wheels or wheel axles of the rail vehicle. In areas 27, 28, however, there are no wheels or wheel axles, but brakes. A relatively small signal in the area of ​​brake 27 is not evaluated as a wheel pulse in measuring area 18, since the measurement signal of the relatively small brake (meaning the relative increase in the voltage induced in the detector coil 14 resulting from the metal mass of the brakes) in area 27 lies below the conventional upper threshold 22. A relatively large brake in area 28, however, generates a measurement signal 19 which lies above the conventional upper threshold 22 and thus leads to evaluation as a counting pulse. In this conventional case, a relatively large brake is therefore incorrectly evaluated as the presence of a wheel, which is indicated by a flash.Embodiments of the present invention can avoid such miscounts by braking, which causes an increase in the induced voltage in the region of the threshold 22).

[0064] According to one embodiment of the present invention, examples of measurement signals and derived pulse counts are illustrated in Fig. 4. The abscissa 15 indicates time, the ordinate 16 indicates the relative induced voltage, and the ordinate 17 indicates a count. An upper threshold 30 and a lower threshold 31 are defined.

[0065] The measurement signals 32 were recorded by a rail vehicle having at least two wheel axles 10a, 10b and a magnetic rail brake 11a. When the measurement signals 32 were recorded, the magnetic rail brake was deactivated, i.e., passive. The measurement signals 32 generated due to the presence of the wheels or wheel axles 10a, 10b and due to the presence of the magnetic rail are all above the upper threshold 30 and are thus counted as pulses in the counting pulse profile 33.

[0066] The measurement signal curve 34 in Fig. 4 illustrates the measurement signals of the same section of the rail vehicle when the magnetic rail brake 10a is activated, i.e. active. In this case, the measurement signals 34 caused by the presence of the wheel axles or wheels 10a, 10b are again above the upper threshold 30. Unlike the measurement signals 32, however, the measurement signal 34 in the area of ​​the active magnetic rail brake is not above the upper threshold 30, but below a lower threshold 31. The upper threshold 30 can, for example, lie in a range of 1.2 to 1.35 of a relative induction voltage (or relative wheel camber). The lower threshold 31 can, for example, lie in a range of 0.8 to 0.9 of a relative induction voltage (or relative wheel camber).Even in the case of the active brake, the evaluation leads to a counting pulse profile 35 which counts both the wheels or wheel axles 10a, 10b as counting pulses as well as the active brake 11a.

[0067] Conventionally observed miscounts in axle counting procedures due to the presence of magnetic track brakes (activated or deactivated) can thus be reduced or even completely prevented.

[0068] Magnetic track brakes are available in various designs, and depending on their design, some of them have a significant impact on the wheel sensor. If the affected vehicles also have small wheels, reliable operation with conventional axle counters is often no longer possible.

[0069] Conventionally caused track clearance faults reduce the availability and ultimately also the acceptance of these systems. Traditionally, attempts are made to set the sensitivity of the counting points so that the wheels of a rail vehicle are always reliably detected and the magnetic track brakes located between the wheels of a bogie are never detected. However, this conventional method only works if the amplitudes of the wheel signals generated at the counting point differ significantly from the amplitudes of the brake signals. If the amplitudes of the wheels and brakes are similar, then setting the counting point with the above requirements is not always possible. In this case, the use of axle counters with counting points can lead to problems with regard to availability.

[0070] Embodiments of the present invention may include the following details, but do not constitute necessary features of the present invention:

[0071] Problems that usually occur can be solved or reduced in a first step if all brakes are reliably counted. However, simple detection and counting of the brakes is only possible when they are in the passive state. In this state, the brakes are not energized and move a few millimeters above the top edge of the rail. Due to the large metal mass, the brakes influence the counting points more or less - depending on the design of the brake and its distance from the sensor. By reducing the (upper) switching threshold (compared to a conventional one), all brakes are reliably counted. Thus, the upper threshold 30 defined according to one embodiment of the present invention can be smaller than a conventionally used upper switching threshold.

[0072] If a vehicle passes a counting point with activated brakes, the signal behavior changes significantly, and conventional signal processing fails at this point. Due to the high magnetic fields under the active brake, the magnetic properties of the rail change (saturation effects). This reduces the received signal at the counting point, and detection like that of wheels is not possible, at least not in the conventional way.

[0073] To remedy this, one embodiment of the present invention proposes also advantageously using the lower switching threshold of the counting points. Conventionally, the lower switching threshold of the counting points serves to detect the sensor's detachment. If, for example, the fastening bolts on the wheel sensor have come loose and the sensor moves away from the rail, this must be disclosed for safety reasons (detachment detection). The undershoot of the lower threshold is conventionally delayed in the counting point and is not immediately transmitted.

[0074] According to one embodiment of the present invention, however, the conventionally applied deceleration is deactivated. Thus, activated brakes generate the same signals when the lower threshold is exceeded as passive brakes when the upper threshold is exceeded.

[0075] According to embodiments of the invention, a method is proposed with which both passive (deactivated) and active (activated) brakes, in particular magnetic track brakes, can be reliably detected and counted like wheels.

[0076] Fig. 5 shows, in coordinate systems with abscissas 15 indicating time and with ordinates 16 indicating the absolute induction voltage or an ordinate 17 indicating the counting pulse, measurement signals 36 of a rail vehicle having eight axles or wheels and, between them or between pairs of wheels, magnetic rail brakes which are activated in the first half of Fig. 5 and deactivated (passive) in the second half of Fig. 5.

[0077] The upper threshold 30 and the lower threshold 31 are also shown. The upper threshold 30 is 1.28, and the lower threshold is 0.85; however, these values ​​can be adjusted depending on the application or the situation.

[0078] Counting pulse profile 37 illustrates that both the wheels or wheel axles and the magnetic track brakes are reliably detected in both the activated and deactivated states. The rail vehicle comprises two carriages, each with two bogies; the magnetic track brakes are active in the first carriage and passive in the second. Using the proposed method and system, a track section can be reliably monitored.

Claims

Patent claims 1. A method for monitoring a track section (2) for the presence or absence of at least a part of a rail vehicle (4) moving on the rail (3a, 3b), the method comprising: Obtaining first measurement signals (6a) from a first sensor (8a) located at the beginning (7) of the track section (2); Obtaining second measurement signals (6b) from a second sensor (8b) located at the end (9) of the track section (2); Evaluating the first measuring signals (6a) and the second measuring signals (6b) in order to register or count incoming metal bodies and to register or count outgoing metal bodies, wherein both axles or wheels (10a, 10b, 10c, 10d) and any brakes (11a, 11b) that may be present are detected as metal bodies; Inferring the presence or absence of the part of the rail vehicle (4) on the track section (2) based on the registration or counting.

2. Method according to the preceding claim, wherein the metal bodies comprise elements of the rail vehicle which are arranged vertically near the rail (3a, 3b), in particular wheels (10a, b, c, d) and / or wheel axles and / or brakes (11a, b) of the rail vehicle.

3. Method according to one of the preceding claims, wherein the evaluation of the first measurement signals (6a) and the second measurement signals (6b) comprises: Determining a first number of first measurement signals (6a) which are above an upper threshold (30) or which are below a lower threshold (31); Determining a second number of second measurement signals (6b) which are above the upper threshold (30) or which are below the lower threshold (31), wherein the upper threshold is greater than the lower threshold.

4. Method according to the preceding claim, wherein a conventionally provided delay of the measurement signals below the lower threshold (31) is suppressed.

5. A method according to any one of the preceding claims 3 or 4, wherein the inference as to the presence or absence of the rail vehicle comprises: Comparing the first number with the second number; inferring the presence or absence of the part of the rail vehicle (4) on the track section (2) from the comparison result.

6. Method according to the preceding claim, further comprising: Concluding that the track section (2) is free of the part of the rail vehicle (4) if the first number is equal to the second number; and / or Concluding that the track section (2) is not free of the part of the rail vehicle (4) if the first number is greater than the second number; and / or Infer that an error has occurred if the first number is less than the second number.

7. Method according to one of the preceding claims 3 to 6, wherein the upper threshold (30) is selected such that a measurement signal caused by a non-activated brake, in particular a magnetic rail brake (11a, b), of the rail vehicle or by a wheel axle or wheel is above it.

8. Method according to one of the preceding claims 3 to 7, wherein the lower threshold (31) is selected such that a measurement signal caused by an activated brake, in particular a magnetic rail brake (11a, b), of the rail vehicle is below and a measurement signal caused by a wheel or a wheel axle is above.

9. Method according to one of the preceding claims 3 to 8, wherein the upper sleeper (30) and / or the lower sleeper (31) are adjusted such that both wheel axles and / or wheels (10a,b,c,d) and any magnetic rail brakes (11a,b) present are counted or registered both in the activated and in the inactivated state, wherein a rail friction contact surface (41) of the magnetic rail brake (in the non-activated state) has a distance of 4 mm to 9 mm from the rail (3b).

10. Method according to one of the preceding claims, wherein the part of the rail vehicle (4) has at least one magnetic rail brake (11a, b), which is in particular temporarily activated or temporarily inactivated.

11. The method according to one of the preceding claims, wherein the first measurement signals (6a) were continuously recorded while the part of the rail vehicle passes / passes over the first sensor; wherein the second measurement signals (6b) were continuously recorded while the part of the rail vehicle passes / passes over the first sensor.

12. Method according to one of the preceding claims, wherein the first sensor (8a) and / or the second sensor (8b) is configured as a metal sensor, in particular a counting point.

13. Method according to one of the preceding claims, wherein the first sensor and / or the second sensor comprises: an electromagnetic generating coil (13) mounted on one side of a rail of the track, for generating an alternating magnetic field; an electromagnetic detecting coil (14) mounted on the other side of the rail of the track, for detecting an alternating magnetic field by inducing a voltage, which in particular represents the measurement signals.

14. Method according to one of the preceding claims, wherein the rail vehicle (4) is a long-distance vehicle or local transport vehicle, in particular a subway, tram or S-Bahn .

15. A system for monitoring a track section (2) for the presence or absence of at least part of a rail vehicle (4) moving on the track, the system comprising: an input port (5a, 5b) configured to receive first measurement signals (6a) from a first sensor (8a) located at the beginning (7) of the track section (2); to receive second measurement signals (6b) from a second sensor (8b) located at the end (9) of the track section (2); an evaluation block configured to evaluate the first measurement signals (6a) and the second measurement signals (6b) in such a way as to register or count incoming metal bodies and to register or count outgoing metal bodies, wherein both axles or wheels (10a, b, c, d) and any brakes (11a, b) are detected as metal bodies;and to infer the presence or absence of the part of the rail vehicle (4) on the track section (2) based on the registration or counting;

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