KR101044681B1 - Process and installation for detecting a rail break - Google Patents

Abstract

The method is for checking the integrity of a section of railway track, comprised of two rails (1, 2) between which is placed a generator (3) or detector at one extremity and an impedance at the other extremity. A detector or generator (3) is arranged in a common mode connector (6). The method involves the following steps: generation of a signal of a given frequency and its application to the track section; capture and detection of the signal using a detector; and processing of the signal to made a deduction about the track integrity. An Independent claim is included for a corresponding installation for checking the integrity of a railway track section, especially for detecting a break in one of the rails.

Description

PROCESS AND INSTALLATION FOR DETECTING A RAIL BREAK}

1a and 1b schematically show the use of a track circuit equipped with a rail breakage detection device in a common mode in accordance with the present invention;

2a to 2d schematically show four forms of a rail breakage detection apparatus according to the present invention;

3 schematically shows a track circuit for detecting the presence of a train between two electrical connections, each having an emitter and a receiver;

4 shows schematically a track circuit for train detection with a device according to the invention for detecting rail breakage;

5 schematically shows a track section comprising two parallel tracks mounted with a rail breakage detection device in accordance with a preferred embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

1, 2: parallel rail 3: generator

4: Impedance 6: Common Mode Link

7: detector 8: wire

10: railway track

TECHNICAL FIELD The present invention relates to a method for monitoring the integrity of a railroad track, and more particularly to a rail break detection method. The invention also relates to an apparatus for implementing this method.

Certain rail transport operators and operators in certain types of transport operations, such as passenger transport routes and lines with speeds of more than 160 km / h, require on-site autonomous real-time systems to detect rail breakage. In practice, the term "real time" is understood to mean any delay that responds at most to a few minutes.

In practice, rail breaks are critical to be detected in real time, as they can cause serious accidents such as derailments, especially in curved track sections.

Moreover, if an initial rail breakage occurs, there is a greater possibility that a secondary breakage will occur next immediately near the initial rail breakage portion. This leads to detection "blanks" or train "losses" in the case of detection systems provided by the track circuit.

The track circuit is known to be a system using two rails as the transport route. Some signals are input in differential form at one point and received by the receiver at another point. The presence of the axle between these points is converted into a resistor that short-circuits the two rails, thus attenuating the received signal. Therefore, this system acts as a detection system that can detect the presence of the axle while maintaining complete security in a predetermined section. A predetermined interval is defined as the length of the interval whose range is defined by two points: emission and reception.

One known convention is to limit this track circuit by introducing an insulated junction (with mechanical discontinuities) or an electrical junction (without mechanical discontinuities) obtained using radio frequency signals in a tuned track circuit, which is currently It is the preferred solution being used. At this time, the track will be divided into sections called "block systems" which are separated by electrical junctions.

According to the art, it is customary to use electrical junctions for large sections of the track, ie between 100 meters and 2 kilometers.

According to this very principle of the track circuit, even if an accidental electrical discontinuity occurs in the rail, no signal should be generated at the receiver, but in practice this is not always the case, and the return to the substation of the ground and traction current of the track. The parasitic path constitutes a parasitic path, which causes the track circuit to avoid currents from breaking the rail and thus obstruct its detection.

Nevertheless, with respect to the grounding point and positioning and the positioning of the return path to the substation of the traction current, detection can be ensured to some extent by following a certain number of rules. Moreover, it is common trend to "pupinize" tracks, ie, install capacitors at regular intervals between two rails, to compensate for the track's self-induction coils per unit length. This makes it possible to relatively increase the power attenuation caused by the unpunished parasitic path. This technique makes it possible to alleviate the drawbacks without removing the capacitors.

It should be noted that this detection using track circuits is highly dependent on external parameters such as ground type, ballast condition, and track geometry (such as with a catenary type or with a third rail). .

Moreover, these techniques do not distinguish between the two events of track occupation and rail breakage. In practice, these events appear as voltage drops in the track circuit. Moreover, it is of course important to be able to distinguish between two types of information, namely rail breakage and track occupancy, while at the same time safely detecting the presence of the train.

Moreover, at present, various solutions proposed in the art can be used only in the case of tracks equipped with track circuits with electrical or mechanical joints, and generally in low-traffic tracks or European Railway Train Management System (ERTMS). It does not apply to tracks with level-3 type signaling.

To date, there is no device capable of detecting rail breaks for this type of track.

It is an object of the present invention to provide a solution which does not have the disadvantages of the prior art by providing a method and apparatus for the reliable detection of rail breakage in the railroad engineering sense.

It is therefore an object of the present invention to provide a solution capable of detecting rail breakage by using a detection related system with a track circuit or by a system not associated with a track circuit.

A further object of the invention is to make it possible to apply the method and apparatus of the invention to a relatively long section of the track, for example several tens of kilometers, in particular in the case of tracks where train detection by the track circuit is not guaranteed.

It is a further object of the present invention to provide a low cost solution which minimizes the number of equipment.

According to the invention, the integrity of at least one section of a railway track is monitored, the section consisting of two parallel rails, and between the two rails a generator or detector at one end and an impedance at the other end are arranged. In the rail track section integrity monitoring method comprising a detector or a generator arranged on a common mode link,

Generating a signal of a specific frequency with the help of the generator and inputting the signal into the section;

Capturing and detecting the signal at the frequency with the aid of the detector, and

It provides a railway track section integrity monitoring method comprising the step of performing the signal processing to perform the integrity diagnosis of the section.

According to a first embodiment of the method of the present invention,

A signal of a specific frequency corresponding to the current in the first circuit corresponding to the section is generated with the help of an AC voltage generator provided between the rails,                         

With the aid of the detector installed in the common mode link, the current at the frequency is captured and detected in an additional circuit consisting of at least one common mode connection linked to the first circuit.

According to the second embodiment,

A signal of a specific frequency is generated from a current generating source disposed in said common mode connection in an additional circuit,

With the aid of the detector, the signal of the frequency is captured and detected in the form of a differential voltage between the two rails in a first circuit corresponding to the section.

In the method of the invention the signal can be coded.

In the method of the invention the common mode link may be a ground connection when the traction current is an AC current. Alternatively, the common mode link may be a connection provided as a return path of the traction current to the substation when the traction current is a DC current.

Furthermore, according to a first embodiment of the device of the present invention, in an apparatus for monitoring the integrity of railway track sections, preferably for detecting rail breakage,

Means for generating a signal disposed between two rails of the railroad track,

An impedance connected between the rails a predetermined distance from the generating means,

A facility disposed between the rails and having intermediate points at least linked to each other by conductors to form a common mode connection;

Means for detecting said signal disposed on said common mode connection, and                         

It provides a railway track section integrity monitoring apparatus comprising a means for performing the processing of the signal to perform the integrity diagnosis of the section.

In the apparatus according to the first embodiment, the signal generating means may be an AC voltage generator, and the signal detecting means may be an AC current detector.

Furthermore, according to a second embodiment of the apparatus of the present invention, preferably in an apparatus for monitoring the integrity of railway track sections in order to detect rail breakage,

Means for detecting a signal disposed between two rails of the railway track,

An impedance connected between the rails a predetermined distance from the detecting means,

A facility disposed between the rails and having intermediate points at least linked to each other by conductors to form a common mode connection;

Means for generating said signal disposed on said common mode connection, and

It provides a railway track section integrity monitoring apparatus comprising a means for performing the processing of the signal to perform the integrity diagnosis of the section.

In the apparatus according to the second embodiment, the signal detecting means may be an AC voltage detector, and the signal generating means may be an AC current generator.

In the device according to the invention the common mode connection may comprise a ground connection via a ground point. Alternatively, the common mode connection may comprise a lead that brings the traction current back to the substation.

In the device according to the invention the installation with the midpoint can be a winding with the midpoint.

In the apparatus according to the first embodiment, the voltage generator may serve as a transmitter (Tx) of the track circuit for train detection, and the impedance may serve as a tuner associated with the receiver (Rx) of the track circuit for train detection. Can be done. The track circuit can be separated from adjacent track circuits by an insulating junction or an electrical junction.

In the apparatus according to the second embodiment, the differential voltage detector may serve as a receiver (Rx) of the track circuit for train detection, and the impedance serves as a tuner associated with the transmitter (Tx) of the track circuit for train detection. Can be done. The track circuit can be separated from adjacent track circuits by an insulating junction or an electrical junction.

According to the invention, the detection means may comprise an instrument transformer comprising a first winding functioning as the primary side, a second winding functioning as the secondary side, and at least one receiver.

According to one embodiment of the invention, the first winding connects the midpoints of two installations with intermediate points belonging to two different tracks A and B, and the at least one receiver is connected to the first track. The current of the first frequency F1 can be detected corresponding to the first track circuit present in (A), and the current of the second frequency can be detected corresponding to the second track circuit present in the second track B. have.

The invention resides in the presence of signal generators, in particular voltage generators or current generators, installed between two rails of a railway track or on a common mode link, as well as detecting the signals indicative of rail cracking and breakage. Any combination of source type (voltage or current) and detector type (measuring current or voltage) may be included within the scope of the present invention.

The term "common mode" is understood to mean a means by which two rails can be joined. Common mode means typically consist of facilities with mid-points, which are midpoints which are interconnected by themselves or connected to ground by means of connections.

1 and 2 schematically illustrate the detection principle of a method and apparatus implemented according to a preferred embodiment. A detailed description can be found with reference to FIG. 3.

1 and 2, an embodiment in which a voltage generation source disposed between two rails is provided and the presence of a common mode current is detected is used. Of course, the exact same analysis can be achieved with the opposite configuration, i.e., a current generating source disposed at the common mode connection and a differential voltage between the two rails is detected.

In the first scenario the track circuit consists of rails 1, 2, between the rails an AC voltage generator 3 of frequency F1 and an impedance 4 which is equivalent to a predetermined impedance of the frequency of the generator 3. Is placed.

This voltage source preferably produces a current that is coded at a lower frequency at longer intervals.

The method according to the invention preferably utilizes a system of coded signals which distinguishes the traction current from the rail breakage detection current.                     

There are also installations 5 (impedance) having an intermediate point that enables grounding when towing with an alternating voltage or allows return of the current to a substation when towing with a direct current. These facilities can achieve a common mode link.

In practice, such installations 5 are pre-installed in the track circuit and are therefore used for the purposes of the present invention.

Such installations 5 with intermediate points in the case of an traction current at an alternating voltage, for example an AC voltage of 50 Hz, 25 kV, have some part of the traction current through the conductor 8 to the ground point 13 (FIG. 2 a). Can be returned. There is then a common mode connection 6 between the two intermediate points of the installations 5.

Such installations 5 also exist to ensure insulation of the track to ground in the case of DC traction currents. In this case the traction current is redirected from the midpoints of the installations 5 through the leads 8 and 14 to the substation 15 (FIG. 2B). The electrical path consisting of two leads 8 and a portion of the leads 14 represents a common mode connection 6. This connection 6 (FIG. 2A or 2B) will be used to detect rail breakage in the track section between the installations 5 according to the invention.

In order to detect the presence of a common mode current, the device 7 capable of measuring the current is preferably arranged at the connection 6 between the installation 5 and the lead 14 or ground point 13 depending on the environment. .

The device 7 can consist of any current measuring instrument known in the art. This, of course, is configured to distinguish between the passage of the traction current and the passage of the current for detecting rail breakage at the frequency F1.

In a normal situation, i.e., in a situation where there is no rail breakage between the generator 3 and the impedance 4, the current I flows through the track circuit 10 (FIG. 1A). The limited portion of the current will pass through the connection 6 due to the inherent asymmetry of the track.

In the case of rail break 11, current I will pass through circuit 12 (FIG. 1B) to increase the current detected by device 7 (towing current + current due to common mode). Therefore, by detecting such an increase in current, it is determined that discontinuity has sufficiently occurred in the rail 1 or the rail 2, and accordingly, the rail breakage can be detected in the track section.

The tuning of the detection method should take into account the track's environment (ground, catenary, etc.). The limits of use depend on the type of traction, the presence of ground or return to the substation and the characteristics of the track.

As shown in FIG. 2, the connections 6 can be made in various forms depending on the characteristics of the track. Basically, there are two possibilities related to the return of the traction current (AC or DC). The traction current is driven by the ground points 13 to the rail of the track in the case of a 25 kV, 50 Hz AC traction voltage (Figure 2a) (at normal distances) or in the case of a direct current traction voltage (Figure 2b). The plurality of points along the way can flow out through the presence of a conductor 14 connecting the substation 15 which is essentially the common track insulation point for many points on the track.                     

2a shows a first embodiment (AC voltage) using ground points 13 which actually connect the midpoints of the installations 5. The installation 5 of the present invention is preferably an inductive impedance (windings) which exhibits a predetermined value at the frequency F1 of the track circuit and exhibits low impedance at low frequencies. These windings can be used in the method of the present invention if the facilities are already present on the track and functioning as the return path of the track current.

Figure 2b shows a second embodiment in the case of a DC voltage, in which the conductor 14 is primarily intended to draw track current towards the substation 15, but to implement the method of the invention. It also functions as the connecting portion 6.

The principle of the present invention is therefore to detect the presence of a common mode current using this connection, either a ground link (FIG. 2A) or a link redirecting towards a substation (FIG. 2B).

Then, a known method is used to measure the current between a point at the midpoint of the winding of the plant 5 and a point at the connection 6, for example ground or at a point on the return path to the substation of the traction current. The signal detected at the frequency F1 in the specific detector 7 present on the connection part 6 means that a rail breakage occurred in the section to be inspected (block system).

2C and 2D show an embodiment in which the current generator 40 and the differential voltage detector 41 are installed between the rails on the common mode connection 6. The system can likewise detect rail breakage by detecting the effect of the rail breakage on the voltage measured by the detector 41.

According to a preferred embodiment, the method of the present invention utilizes already existing track circuits, such as track circuits, which are used to locate a train and are separated by electrical junctions.

Conventionally, electrical junctions of the type shown in FIG. 3 (called Rx / Tx junctions) are two tuning units, TU.RX ("tuner-receiver") and TU.TX ("tuner-transmitter"). "), Which are arranged between two rails 1 and 2 at a distance of 15 to 30 m from each other to connect the two rails to each other. The distance between two adjacent junctions can vary between several hundred meters to one or two kilometers. Thus, each junction separates the track into two sections 50, 60 corresponding to the distance between the two tuning sections, with overlapping regions 70 called "block systems". The presence of trains is detected at frequencies representing each block system by an electrical signal present in a circuit corresponding to the block system, thereby enabling electrical separation of two adjacent circuits.

3 shows two electrical junctions defining the track circuit limits. The tuning portion 20 of the rear junction and the tuning portion 31 of the right junction are equivalent in capacitance at the first frequency F1. At this frequency, the AC source Tx emits a signal into the track circuit, which is delimited by the two junctions. In practice, the generation source Tx is connected in series with the tuning section 20. The tuning section 21 is provided with a receiver Rx in parallel, and the tuning section 21 is basically a current in a track circuit. It includes a device for measuring. The track circuit corresponding to the block system 50 is separated from the adjacent circuits 60 due to the fact that the outer tuning parts 22, 23 are short-circuited at the frequency F1. At other frequencies F3, in contrast, these tunes are equivalent in capacitance, and in this way can detect the presence of trains in the adjacent block system 60 by current at this frequency F3.

For example, train detection on the block system 50 is due to the fact that the axle 24 of this train constitutes a short circuit between the rails 1, 2 inherently. In practice, this axle exhibits a low impedance similar to a short circuit, and this low impedance results in voltage intensification at the receiver connected to the tuning section 21, causing the receiver to stop operating. Therefore, such an operation stop corresponds to train detection between the tuning units 20 and 21.

This situation is obviously similar to that shown in FIG. By using the common mode connection part 6 provided with the installation apparatus 5 and the electric current measuring apparatus 7 which have an intermediate point, it is possible to detect a rail breakage in each block system safely as shown in FIG. The installations 5 with intermediate points are inductive impedances and do not necessarily have to be located between the tuning portions of the electrical junction.

Furthermore, it is possible according to the method of the invention that the monitored track intervals comprise several detection track circuits. This allows the installations 5 with intermediate points to be installed close to a limited number of joints along the track, rather than to each electrical joint.

Thus if there is a train on the track circuit 50 it will be observed that the current passes through the axle of the train and does not pass through the connection 6. Traction current is measured by the device 7 at the moment the train passes.

Thus, if proper coding of the signal makes it possible to distinguish the traction current from the common mode signal used to detect the rail break, there is confusion between the detection of the rail break and the presence of the train on the track section corresponding to the track circuit 50. There will be no.

A preferred form of embodiment of the present invention is shown in FIG. Current is measured for two parallel pairs A and B of rails 1, 2 and 1 ', 2'. Two tracks A and B are provided with track circuits for train detection, and the track circuits are separated by electrical junctions 20, 22 and 22, 23. In this particular case, the current measuring device 7 is in the form of an instrument transformer 18, 19, 32 which can detect a rail break in each of the two block systems 30, 31 belonging to each of the two parallel tracks. . Train detection in the block systems 30 and 31 is performed by differential signals of different frequencies, F1 and F2. A facility 5, 5 'with a midpoint exists between the tuning portions of the electrical junction.

Impedance 18 consists of a magnetic induction coil which acts as the primary side of the instrument transformer, for example in the case of an AC voltage, and whose midpoint is grounded. In the case of a DC voltage, the midpoint can be connected to a cable which acts as a return connection to the substation. In this case, the detection of two currents in two circuits of the parallel track can be achieved by one measuring instrument. Two windings 18 are used if ground is to be provided as shown in FIG.                     

At least one particular receiver 32 for detecting rail breakage is connected to the secondary side 19 of the transformer.

This is to avoid identifying the presence of the train with virtual destruction, so a coded track circuit signal is used.

Thus, preprogrammed pairs of frequency codes can be used to determine (or more accurately distinguish) current from the track circuit and traction current. Receiver 32 detects a signal above a certain threshold corresponding to the determined frequency (filtering) and coding. By such detection, it is possible to determine a block system or track in which an abnormal situation exists.

It is possible to use one receiver 32 per ground point if the receiver 32 is provided with means (e.g. coding means) for distinguishing between a signal at frequency F1 and a signal at frequency F2. Preferably two receivers 32 per ground point, i.e. one receiver per frequency F1, F2, will be installed. These receivers will be installed in parallel with the secondary winding 19.

As shown in FIG. 5, rail breaks in either of the two block systems 30, 31 are detected by the current measuring devices 18, 19, 32. Adjacent block systems will be monitored by similar devices 18 ', 19', 32 'connected to inductive connections 5' proximate adjacent junctions. Indeed, the presence of a ground junction near the electrical junction must be involved in common mode conduction associated with rail failure in this section. In conclusion, there is no need to detect this signal at adjacent ground junctions.

The current sensors 18 and 19 and the detector 32 are preferably housed in one housing, for example through which a conductor through which a common mode current flows. Detection by detector 32 may be effected at the track or at some distance from the track.

According to the invention the rail breakage can be detected using a detection circuit with a track circuit or a system not related to the track circuit, for example in the case of a track where the train detection by the track circuit is not guaranteed. It can be applied to relatively long sections of several tens of kilometers and can also provide a low cost solution to minimize the number of equipment.

Claims (19)

A method for monitoring the integrity of two segments belonging to two railway tracks (A and B), each said segment corresponding to a railway track consisting of two parallel rails (1 and 2; 1 'and 2'). Between the rails, a generator 3 present at one end or an impedance 4 present at the other end is disposed, and a detector (if the end is the generator 3 at a common mode link 6). 7) or if the end is the detector, a generator is arranged and the common mode link 6 comprises devices with intermediate points, arranged between the rails, the intermediate points being at least the conductors 8. Connected by a detector, the detector is an instrument transformer comprising a first winding 18 functioning as a primary coil, a second winding 19 functioning as a secondary coil and at least one receiver 32, the method comprising , For each section, generating a specific frequency signal by the generator and inputting the signal to the section; For each section, acquiring and detecting the signal by the detector; And For each section, performing the processing of the signal and performing integrity diagnosis of the section; The first winding 18 connects the midpoints of two devices 5 with midpoints belonging to two different tracks A and B, and the at least one receiver 32 The second frequency F2 corresponding to the second track circuit present in the second track B, which can detect the current of the first frequency F1 corresponding to the first track circuit present in the first track A, can be detected. The railroad track section integrity monitoring method, characterized in that the current can be detected. The method of claim 1, In the first circuit 10 corresponding to the section, a signal of a specific frequency is generated by the generator 3, which is an AC voltage source disposed between the rails 1 and 2 and the signal is a current. being; And In a further circuit 12 composed of at least one common mode link 6 connected to the first circuit 10 the current of the particular frequency is provided by the detector 7 arranged in the common mode link 6. Integrity monitoring method of a railroad track section characterized in that it is captured and detected. The method of claim 1, In a further circuit 12 a signal of a certain frequency is produced from said generator, said generator being a current source disposed in the common mode link 6; And And the signal of the specific frequency is detected and captured in the form of a differential voltage between two rails by the detector in a first circuit (10) corresponding to the section. 4. A method as claimed in any preceding claim, wherein said signal is coded. 4. A method as claimed in any one of the preceding claims, wherein the common mode link (6) is a ground connection when the traction current for the vehicle is AC current. . 4. The common mode link (6) according to any one of claims 1 to 3, characterized in that the common mode link (6) is a connection portion that functions as a return path to the substation of the power supply current when the power supply current for the vehicle is a DC current. How to monitor the integrity of railroad track segments. A device for monitoring the integrity of railroad track segments, Signal generating means (3) disposed between the two rails (1 and 2) of the railway track and generating a signal; An impedance (4) connected between the rails (1 and 2) a predetermined distance from the signal generating means (3); Devices (5) disposed between the rails (1 and 2) and having intermediate points, which are connected by at least conductors (8) to form a common mode link (6); As the signal detecting means 7 for detecting the signal generated by the signal generating means 3, arranged in the common mode link 6, the first winding 18 functioning as a primary coil, as a secondary coil. An instrument transformer comprising a functioning second winding 19 and at least one receiver 32; And Means for performing processing of the signal and performing integrity diagnosis of the interval; The first winding 18 connects the midpoints of the two devices 5 with the midpoints belonging to two different tracks A and B, and the at least one receiver 32 The second frequency F2 corresponding to the second track circuit present in the second track B, which can detect the current of the first frequency F1 corresponding to the first track circuit present in the first track A, can be detected. The railroad track section integrity monitoring device, characterized in that the current can be detected. 8. Integrity monitoring device according to claim 7, characterized in that the signal generating means (3) consists of an AC voltage source and the signal detecting means (7) consists of an AC current detector. A device for monitoring the integrity of railroad track segments, As a signal detecting means for detecting a signal disposed between two rails 1 and 2 of a railroad track, a first winding 18 functioning as a primary coil, a second winding 19 functioning as a secondary coil and at least one An instrument transformer comprising a receiver 32; An impedance (4) connected between the rails (1 and 2) a predetermined distance from the signal detecting means; Devices (5) disposed between the rails (1 and 2) and having intermediate points, which are connected by at least conductors (8) to form a common mode link (6); Signal generating means (40) for generating said signal detected by said signal detecting means, arranged in said common mode link (6); And Means for conducting an integrity diagnosis of the section by processing the signal; The first winding 18 connects the midpoints of the two devices 5 with the midpoints belonging to two different tracks A and B, and the at least one receiver 32 The second frequency F2 corresponding to the second track circuit present in the second track B, which can detect the current of the first frequency F1 corresponding to the first track circuit present in the first track A, can be detected. The railroad track section integrity monitoring device, characterized in that the current can be detected. 10. The apparatus of claim 9, wherein said signal detecting means comprises an AC voltage detector and said signal generating means comprises an AC current source. Device according to one of the claims 7 to 10, characterized in that the common mode link (6) comprises a ground connection via ground points (13). 11. Integrity of a railway track section according to any of the claims 7 to 10, characterized in that the common mode link (6) comprises a conductor (14) for returning the power supply current for the electric vehicle to the substation (15). Monitoring device. 9. Integrity monitoring device according to claim 7 or 8, characterized in that the devices (5) with a midpoint are windings with a midpoint. The voltage source of claim 8, wherein the voltage source acts as a transmitter (Tx) of the track circuit for train detection, and the impedance (4) acts as a tuner (21) associated with the receiver (Rx) of the track circuit for train detection. Integrity monitoring device of the railway track section, characterized in that performing. 11. The voltage detector of claim 10, wherein the voltage detector acts as a receiver (Rx) of the track circuit for train detection, and the impedance (4) acts as a tuner (20) associated with the transmitter (Tx) of the track circuit for train detection. Integrity monitoring device of the railroad track section, characterized in that for performing. 16. The device of claim 14 or 15, wherein the track circuits are separated from adjacent track circuits by an insulating junction. 16. The apparatus of claim 14 or 15, wherein the track circuits are separated from adjacent track circuits by electrical junctions. 10. The integrity monitoring device according to claim 7 or 9, wherein the monitoring device is for detecting a rail breakage. delete

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