NL2036435B1

NL2036435B1 - Method for safe operation on a rail track and associated safety device

Info

Publication number: NL2036435B1
Application number: NL2036435A
Authority: NL
Inventors: Pim Van Der Schrieck Maarten; Jan Kranenburg Wichert
Original assignee: Build Connected B V
Priority date: 2023-12-06
Filing date: 2023-12-06
Publication date: 2025-06-17
Also published as: WO2025120161A1

Abstract

A method for safely operating on or around a rail track equipped with a wheel detector device, a safety device and a system for a wheel detector device comprising a magnetic ﬁeld generating means generating a magnetic ﬁeld, at least one magnetic ﬁeld sensor, each sensor sensing a respective magnetic field value, and a processor in communication with the at least one magnetic ﬁeld sensor for detecting the passing of a wheel on a rail of the rail track on the basis of at least one sensed magnetic ﬁeld value. The method comprises the following 10 steps: providing a safety device comprising at least one ferromagnetic plate conﬁgured to mimic a wheel for the wheel detector device, bringing the safety device onto or near the wheel detector device.

Description

METHOD FOR SAFE OPERATION ON A RAIL TRACK AND ASSOCIATED SAFETY

DEVICE

The present invention relates to a method for safely operating on a rail track equipped with a wheel detector device placed next to a rail track. The present invention further relates to safety device for a wheel detector device, a wheel detector system comprising a wheel detector device and such a wheel detector safety device, and a method for testing a wheel detector device using the wheel detector safety device.

In many applications concerning rail tracks, such as in rail transport with trains, itis beneficial to obtain information on the whereabouts of train vehicles. Many marshalling yards, especially those without electrified systems, lack safety systems.

In a previous patent application WO2021/004800, the present Applicant has described a method and device for detecting a direction of motion of a wheel on a rail track, comprising least one magnet for providing a magnetic field; a magnetic field sensor for sensing a magnetic field value indicative for a flux density, or a change in the flux density, of the provided magnetic field; at least one processor in communication with the magnetic field sensor, wherein the at least one processor is configured to: obtain a plurality of the magnetic field values for respective times from the magnetic field sensor; and to analyse the obtained plurality of magnetic field values such that a direction of motion of a wheel passing the device is obtained.

The present Applicant has further developed in NL application N2035850 a device for detecting a wheel on a rail track, wherein the device is configured to be placed at a lateral side of the rail track. The device comprises: - at least one magnet for providing a magnetic field; - a first magnetic field sensing unit for sensing a first magnetic field value indicative for a flux density. or a change in the flux density, of the provided magnetic field; - a second magnetic field sensing unit for sensing a second magnetic field value indicative of a background magnetic field component, - at least one processor in communication with the first magnetic field sensing unit and the second magnetic field sensing unit, wherein the at least one processor is configured to obtain the first magnetic field value from the first magnetic field sensing unit, obtain the second magnetic value from the second magnetic field effect sensing unit, calculate a background compensated magnetic field value on the basis of the first magnetic field value and the second magnetic field value, and detect the passing of a wheel on the rail track above the device on the basis of the calculated background compensated magnetic field value.

Such detector devices are also referred to as axle counters.

When a trackworker is present on or near the rail track, moving trains may form a risk to the safety of the trackworker. Furthermore, the trackworker may be hindered by the magnetic field generated by the wheel detector, for instance when the trackworker is using equipment comprising metal, as the strength of the magnetic field created by the wheel detection device is considerable.

It is therefore an object of the present invention, amongst other objects, to improve the safety for trackworkers.

Thereto, a method for safely operating on a rail track equipped with a wheel detector device placed next to a rail track, the wheel detector device comprising a magnetic field generating means generating a magnetic field, at least one magnetic field sensor, each sensor sensing a respective magnetic field value and a processor in communication with the at least one magnetic field sensor for detecting the passing of a wheel on a rail of the rail track on the basis of at least one sensed magnetic field value, wherein the method comprises the steps of providing a safety device comprising at least one ferromagnetic plate configured to mimic a wheel for the wheel detector device, and bringing a safety device onto or near the wheel detector device. In this way, the detector may react as if a wheel would be present, informing accordingly a railway operator, such that no trains are allowed to enter the track sections containing the wheel detector. The safety of a trackworker operating on the rail track is thus ensured without turning off the wheel detection device. Such a solution does not entail any hardware modification on the wheel detection device and does not require any moving mechanical parts subject to wear and tear like mechanical switches. Such solution may be easily retrofitted on existing rail tracks equipped with any kind of wheel detector devices based on the principle of sensing a magnetic disturbance created by a passing metallic wheel. In addition, the ferromagnetic plate damps (attenuates) the magnetic field around the detector device, reducing magnetic interactions between any metallic object in the vicinity of detector device and the detector device. This may improve the safety of operation for trackworkers and their equipment around said detector device. It is noted that although the method is described for safely operating on a rail track already equipped with a wheel detector device, the same concept would apply for methods of safely operating around a wheel detector device, such as a method for safely installing such a wheel detector device on a rail or a method for safely transporting a wheel detector device, in as much as it comprises bringing a safety device onto or near the wheel detector device to improve the safety of operation around said wheel detector device.

According to a preferred embodiment, bringing a safety device onto or near the wheel detector device comprises attaching the safety device onto the wheel detector device, preferably as a cover device over the wheel detector device. In this way, the at least one ferromagnetic plate may modify/disturb the magnetic field created by the magnetic field generating means and sensed by the magnetic sensor just like a wheel would. The safety device may operate as a cover or cap (both terms are used in the rest of the text interchangeably) and may magnetically interact with the field created by the magnetic field generating means to mimic a wheel from the point of view of the detector device.

According to a preferred embodiment, attaching the safety device onto the wheel detection device comprises magnetically attaching the safety device securely onto the detection device based on the magnetic attraction between the at least one ferromagnetic cover plate member and the magnetic field generating means. In this way, the cap can be securely fixed onto the detector device and accidental removal is prevented. The magnetic attraction may prevent external environmental factors, like wind or rain for instance, from removing the cap from the detector device. The removal of the cap is then conditioned by a trackworker exerting a substantial effort to decouple the cap from the detector device. The ferromagnetic cover plate member serves in that sense both to securely attach the cap onto the detector device and to mimic the wheel, further thus increasing the safety for the trackworker.

According to a preferred embodiment, the method further comprises further verifying the correct attachment of the safety device onto the wheel detection device via a light indicator. In this way, the safety of operation may be further increased.

According to a preferred embodiment, the detector device comprises an additional magnetic sensor for sensing an additional magnetic field value, and the safety device comprises a magnet generating a confirmation magnetic field to be picked up by the additional magnetic sensor, the method comprising further confirming the presence of the safety device onto the wheel detection device when the sensed additional magnetic field value amounts to the confirmation magnetic field. In this way, an additional step of protection is offered to confirm that the detector device has been covered by a safety device and is not malfunctioning.

According to a preferred embodiment, the method further comprises performing maintenance on the rail track and/or on the wheel detector device. As long as the safety device is in place, the rail operator may derive the presence of a standing object and prevent trains from entering the track sections in question, such that maintenance operations may be performed safely by a trackworker.

According to another aspect, a safety device for a wheel detector device that is placed next to a rail track is provided. The wheel detector device comprises a magnetic field generating means for generating a magnetic field, at least one magnetic field sensor, each sensor sensing a respective magnetic field value, and a processor in communication with the at least one magnetic field sensor for detecting the passing of a wheel on a rail of the rail track on the basis of at least one sensed magnetic field value. The safety device is arranged to be a cover device removably attached onto the wheel detector device and comprises at least one ferromagnetic cover plate member that mimics a wheel for the wheel detector device. The ferromagnetic plate cover member may be embodied as a ferromagnetic plate having a predetermined thickness and a predetermined surface area. As such, one face of the cover plate member may face the magnetic field generating means, and the other face of the cover plate member may face the rail track. Preferably, the ferromagnetic cover plate member is made of steel.

At the start of a task on or near the rail track, such as maintenance of the track or track-side equipment, a trackworker can place the safety device onto the wheel detector device such that the ferromagnetic cover plate member (or cover plate) is positioned between the magnetic field generating means and the rail. By positioning the cover plate between the magnetic field generating means and the rail, the cover plate affects the magnetic field in such a way that the cover plate mimics a wheel and thus simulates the presence of a wheel on the rail track at the wheel detector device. The magnetic field sensor may then generate a signal communicated to the processor which will be processed by processor for indicating the presence of a wheel on the rail track even though no wheel is actually present. In other words, the at least one ferromagnetic cover plate member simulates for the processor the presence of a wheel, i.e, for as long as the safety device remains attached, it simulates the presence of a standing still train. This information may then be communicated to railways operator in charge of the rest of the railway system to forbid trains from entering the railway sections in which the detection device is located. This allows trackworkers to safely work on or near the rail track. This solution is advantageous over the option of turning manually a switch on the wheel detection device when performing maintenance because any movable element like a switch typically reduces the robustness and reliability of the system.

After completion of the task, the trackworker can simply remove the safety device to allow normal operation of the wheel detector device and normal traffic to resume.

According to a preferred embodiment, the safety device is arranged to be removably attached onto the wheel detector device, preferably as a cover over the wheel detector device, and the at least one ferromagnetic cover plate member is positioned in between the at least one magnetic field generating means and the rail. In this way, the safety device may operate as a cap or cover and may magnetically interact with the field created by the magnetic field generating means to mimic a wheel from the point of view of the detector device. If the wheel detector device comprises two or more magnetic field generating means, it is preferred if the at least one ferromagnetic cover plate member is positioned between each of the magnetic field generating means and the rail. For instance, a plurality of ferromagnetic cover plate members may be respectively positioned between the respective magnetic field generating means and the rail.

According to a preferred embodiment, the at least one ferromagnetic cover plate member has a thickness selected to mimic for the processor of the wheel detection device a wheel. The thickness of the ferromagnetic cover plate may, additionally or alternatively, be dimensioned based on the strength desired to remove the cap, i.e. based on safety regulations.

The safety device may comprise a body, which seen when placed onto the wheel detector device, may comprise a top, a bottom, a front, a rear, a rail side facing the rail, and a detector side 5 facing the detector device away from the rail. The at least one ferromagnetic cover plate member is in use fixed to the rail side of the body of the safety device.

According to a preferred embodiment, the safety device is arranged to be removably magnetically attached onto the wheel detector device based on the magnetic attraction between the at least one ferromagnetic cover plate member and the magnetic field generating means.

Advantageously, as the magnetic field generating means of the wheel detector attracts the ferromagnetic cover plate member with substantial strength, the safety device can be magnetically attached to the wheel detector device in a secure manner such that the cover plate remains in place on the wheel detection device, which improves the overall reliability of the trackworker safety system without the need for additional fastening means.

According to a preferred embodiment, the safety device is arranged to be removably attached onto a sensing side housing part of the wheel detector device containing the at least one magnetic field generating means and the magnetic field sensor, and the safety device comprises a body provided with a detector receiving recess shaped to receive said sensing side housing part for attaching the body onto said sensing side housing part, wherein the at least one ferromagnetic cover plate member is attached to the body and extends alongside of the detector receiving recess.

By receiving the housing part containing the detector components in the recess of the body of the safety device, the safety device can be arranged onto the wheel detector device in a secure manner and the cover plate can be positioned close to the magnetic field generating means.

According to a preferred embodiment, the detector receiving recess extends through a side of the body parallel to the side holding the at least one ferromagnetic cover plate member. In this way, the safety device can be placed onto the sensing side housing part of the wheel detector device from above or sideways, respectively. It is more preferred if the detector receiving recess is open in both the bottom and the detector side, wherein the opening of the detector receiving recess extends continuously from the bottom to the detector side.

According to a preferred embodiment, the safety device is arranged to be removably attached onto the rail, and the safety device comprises a body provided with a rail receiving recess shaped to receive said rail for attaching the body onto the rail, wherein the at least one ferromagnetic cover plate member is attached to the body and extends alongside of the rail receiving recess. The body may then be removably attached onto the rail such that the ferromagnetic cover plate member is positioned between the magnetic field sensor and the rail. In this way, the safety device may be brought in proximity of the detector device while keeping full access to said detector device. An embodiment can be envisaged with a rail receiving recess and without a detector receiving recess in which the safety device is not suitable to be removably attached onto the wheel detector device. The dimensions of the body of the safety device and the thickness of the cover plate may be selected such that the cover plate mimics a wheel for the detector device while the safety device is attached to the rail. In another embodiment, the safety device when attached onto the rail may be used for testing the detector device by moving said safety device to simulate a passing wheel. Optionally an additional testing plate member may be added for that testing purpose as discussed later on.

According to a preferred embodiment, the rail receiving recess extends through sides of the body perpendicular to a side holding the at least one ferromagnetic cover plate member. In this way, the alignment between the safety device and detector device can be manually changed by moving the safety device such that the rail receiving recess receives another portion of the rail.

A preferred embodiment of the safety device further comprises a nonmagnetic outer bumper layer, the outer bumper layer being arranged on a same side of a body holding the ferromagnetic cover plate member, the outer bumper layer forming an outer surface of the safety device. The bumper layer may be made of solid rubber or ethylene propylene diene monomer rubber. Preferably, the bumper layer has a Shore hardness in the range of 20 to 80, preferably in the range of 30 to 70, more preferably in the range of 40 to 60.

The magnetic field generating means generates a strong magnetic field creating potentially dangerous situations in the vicinity of the wheel detector device. The wheel detector device may attract (if attached) or be attracted (if not attached) by objects in the vicinity having magnetic properties (rail, vehicle, toolbox, another detector, etc). By covering the wheel detector device with the safety device and providing the safety device with a bumper layer on the side of the safety device holding the cover plate, the safety of operations around the wheel detector device can be increased. The safety device when placed on the detector device damps (attenuates) the magnetic field created by the detector device in the vicinity to a reduced remaining magnetic field while the bumper layer reduces the risks of hard uncontrolled attraction collisions due to this remaining magnetic field of the detector device. During installation, if a trackworker would for instance have his fingers in between a moving (e.g., not yet fixed, for instance handheld) detector device covered with a safety device and the rail, the operator’s fingers could get dangerously pinched in between the two. Similarly during maintenance, if a trackworker would for instance have his fingers in between an installed detector device covered with a safety device and a large metallic tool, the operator’s fingers could get dangerously pinched in between the two. The bumper layer may absorb the collisions due to any remaining magnetic field around the detector device (despite the safety device) and increases thus the safety around the wheel detector device, and in particular the safety of a trackworker during installation, removal, maintenance and/ or transport of the detector device(s).

According to a preferred embodiment, the safety device further comprises a ferromagnetic testing plate member for testing operation of the detector device, said testing plate member extending parallel to the cover plate member. This way, the safety device can be used as a wheel detector testing device for testing the wheel detector device as described in the testing method embodiment. The ferromagnetic testing plate member is preferably fixed to a side of a body holding the cover plate. It is then preferred if the ferromagnetic testing plate member covers the ferromagnetic cover plate member such that the cover plate is positioned closer to the magnetic field generating means when the safety device is attached to the wheel detector and, when the safety device is placed on the rail, the testing plate is positioned closer to the magnetic field sensor.

This way, the functioning of the respective ferromagnetic plate members can be optimised.

Alternatively, the ferromagnetic testing plate member may be integral with the ferromagnetic cover plate member. Preferably, the ferromagnetic testing plate member is shaped as a disk segment. In this way, the shape of a wheel may also be mimicked.

According to a further preferred embodiment, the safety device comprises a body to which the testing plate member and the cover plate member are attached, wherein said body is further provided with at least a first guiding portion arranged for guiding the safety device in a sliding movement along the rail for translating the ferromagnetic testing plate member past the magnetic field sensor. Preferably. the body is further provided with a second guiding portion spaced from the first guiding portion and arranged for guiding the safety device in said sliding movement along the rail. By providing two guiding portions at a mutual distance, the sliding movement of the safety device can be guided in a stable manner. The guiding portions are preferably provided in the front and the rear of the body of the safety device.

Each guiding portion is preferably provided with a rail receiving recess shaped to receive the rail for placing the safety device on the rail. As the guiding portions are provided in the front and the rear of the body of the safety device, the at least one rail receiving recess is open in the front and the rear of the body. As such, the guiding portions, or the front and the rear of the body, may be each inverted U-shaped. For compactness, it is preferred if the at least one rail receiving recess at least partially corresponds to the detector receiving recess.

According to a preferred embodiment, the first and second guiding portions are arranged on parallel sides of the body which are perpendicular to a side to which the ferromagnetic testing plate member is attached. In this way the ferromagnetic testing plate member may remain parallel to the sliding direction, i.e. parallel to the longitudinal direction of the rail mimicking the displacement of a wheel along the rail track.

A further preferred embodiment of the safety device further comprises a handle for manipulating the safety device, wherein the handle is arranged preferably on a top surface of the safety device, such as to move from above the safety device onto or away from the wheel detector device or the rail. The handle allows a trackworker to effectively grip the safety device for removing the safety device from the wheel detector device with sufficient strength to overcome the magnetic force securing the safety device to the wheel detector device. The handle is preferably provided on the top of the body, which has been found to further facilitate removal of the safety device from the wheel detector device.

According to a further preferred embodiment of the safety device, the body is monolithic.

Preferably, the body is monolithic with the handle.

According to a further preferred embodiment of the safety device, the body is made of polyoxymethylene (POM). This material has low magnetic susceptibility and thus allows the safety device to be conveniently placed onto the wheel detector device as, in essence, only the ferromagnetic plate member is attracted by the magnetic field generating means of the wheel detector. Furthermore, due to its low-friction properties, POM is particularly suitable when the safety device is to be used as a wheel detector testing device that is to be moved along the rail in a sliding manner as described above. Alternatively to POM, it is noted that any non-magnetic material with a suitable rigidity may be used for the body depending in circumstances.

A further preferred embodiment of the safety device further comprises a light and an electromagnetic coil for receiving energy from the wheel detector device and powering the light therewith when the safety device is attached to the wheel detection device. The electromagnetic coil may receive energy from an electromagnetic coil positioned within the detector device through which an alternating current may be sent. The light can function as an indicator light, indicative of correct placement of the safety device onto the wheel detector device. It is thereto preferred if the light is arranged to be turned on only when the energy received in the coil exceeds a preset threshold which is reached when the safety device is correctly placed onto the wheel detector device. In another embodiment, the energy for powering the light may be generated and sent to the safety device only if the wheel detection device detects a wheel standing still. The wheel detection device may thus be configured to condition the generation of the AC signal powering the electromagnetic coil and the light of the safety device to a continuous detection of a wheel during a predetermined time period. Such a continuous detection would then be indicative of a wheel standing still in front of said detector. In this way, the light may act as an indicator of correct placement of the safety device.

Further provided is a wheel detector system, comprising a wheel detector device for detecting a wheel on a rail track, the wheel detector device being configured to be placed next to the rail track, wherein the wheel detector device comprises a magnetic field generating means for generating a magnetic field, at least one magnetic field sensor for sensing a magnetic field value, and a processor in communication with the magnetic field sensor for detecting the passing of a wheel on a rail of the rail track on the basis of the at least one sensed magnetic field value, wherein the system further comprises a safety device according to any of the preceding embodiments.

Preferably when the safety device is arranged onto the detector device, the safety device is magnetically attached onto the wheel detector device based on the magnetic attraction between the at least one ferromagnetic cover plate member and the magnetic field generating means. The magnetic field generating means is in other words arranged to secure the safety device to the wheel detector device by attracting the safety device using the magnetic field.

According to a preferred embodiment, the wheel detector device comprises a sensing side housing part containing the magnetic field generating means and the magnetic field sensor, wherein the safety device comprises a body to which the ferromagnetic cover plate member is attached, wherein the body of the safety device is provided with a detector receiving recess shaped to receive said sensing side housing part for attaching the body onto said sensing side housing part, wherein the at least one ferromagnetic cover plate member extends alongside of the detector receiving recess. By receiving the housing part containing the detector components in the recess of the body of the safety device, the safety device can be arranged onto the wheel detector device in a secure manner and the cover plate can be positioned close to the magnetic field generating means.

According to yet another aspect, a method is provided for testing a wheel detector device for detecting a wheel on a rail track, wherein the wheel detector device is placed next to the rail track and comprises magnetic field generating means arranged to generate a magnetic field, at least one magnetic field sensor arranged to sense a magnetic field value and a processor in communication with the magnetic field sensor for detecting the passing of a wheel on a rail of the rail track on the basis of the at least one sensed magnetic field value, wherein the method comprises the following steps: providing a wheel detector safety device according to an embodiment with a testing plate; placing the safety device onto the rail and moving the safety device over the rail along the longitudinal direction of the rail track in front of the wheel detector device such that the ferromagnetic testing plate member is moved between the wheel detector device and the rail: verifying if the processor generates accordingly a predetermined answer associated with the ferromagnetic testing plate member. In this way, the ferromagnetic testing plate member may mimic a wheel passing in front of the detector. It this “dummy” wheel is not detected, it may be concluded that the detector device is defective.

According to a preferred embodiment, the step of moving the safety device over the rail along the longitudinal direction of the rail track in front of the wheel detector device comprises guiding the safety device using the guiding portions such that the ferromagnetic testing plate member is translated past the at least one magnetic field sensor.

In the following, the present invention is further illustrated with reference to the appended drawings, wherein: - Figures 1 and 2 represent different isometric views of a safety device according to an embodiment; - Figure 3 represents an exploded view of the safety device shown in Figures 1-2; - Figure 4 represents a cross-sectional view of the safety device as shown in Figures 1-2; - Figure 5 illustrates the safety device shown in Figures 1-4 placed on a wheel detector device next to a rail; - Figure 6 represents a cross-sectional view of the safety device as shown in Figure 5; - Figure 7 illustrates the safety device shown in Figures 1-4 placed on a rail next to a wheel detector device; - Figure 8 represents a cross-sectional view of the safety device as shown in Figure 7.

In Figures 1-4, a wheel detector cover device, also called safety device or cap 1 for a wheel detector device is shown. The cap 1 comprises a polyoxymethylene body 2, which comprises a top surface 21, a bottom surface 22, a two lateral side surface 23, 24, and two longitudinal side surfaces 25, 26. In use, when the cap 1 is attached onto a detector device to cover a sensor part of the detector device, the top surface 21 and the bottom surface 22 are oriented horizontally while the two lateral side surfaces 23, 24, and the two longitudinal side surfaces 25 and 26 are oriented vertically. Further, the body 2 is provided with a recess 20 for receiving a sensor part of the detector device when attaching the cap 1 onto the detector device as illustrated in Figures 5 and 6, in which the detector device 10 is shown placed next to a rail 9 for rail vehicles such as trains. The opening of the recess 20 extends continuously from the bottom 22 to the longitudinal side 26. The longitudinal side 26 of the cap 1 is formed as an inverted U-shaped portion with two legs extending when the cap is attached onto the detector device 10 on either side of (the sensor part of) the detector devicelO.

A rail 9 has typically a cross section profile comprising a foot, a web extending vertically with two lateral side surfaces 90 and a head with a horizontal surface 91. When using the x,y, z axis referential illustrated in Figures 5-8 with respect to the rail 9 (and the detector device 10 when in use), the x axis will be referred to as extending in a longitudinal direction, i.e., along the longitudinal direction of the rail 9, the y axis will be referred to as extending in a vertical direction, 1.e., perpendicular to the horizontal surface 91 of the head of the rail 9, and the z axis will be referred to as extending in a lateral direction, i.e., perpendicular to the lateral side 90 of the rail 9.

The safety device of Figures 1-4 is meant for covering a detector device 10 as illustrated in

Figures 5 and 6, comprising two magnets (not shown) for generating a magnetic field, which are mutually spaced along the rail 9 or x axis, two magnetic field sensors 11, 12 for sensing magnetic field values and a microprocessor in communication with the two magnetic field sensors for detecting the passing of a wheel on the rail 9 on the basis of the sensed magnetic field values. The first and second magnets are oriented substantially perpendicular to a sensing side 15 of the detector device 10. The magnetic pole directions of the first and second magnets are inverted and substantially perpendicular to the sensing side 15 (i.e., the magnetic directions are thus horizontal in use). A first magnetic field sensor 12 of the detector device 10 may be used for sensing a first magnetic field value indicative for a flux density, or a change in the flux density, of the magnetic field provided by the magnets. A second magnetic field sensor 11 may be used for sensing a second magnetic field value from the second magnetic field sensing unit indicative of a background magnetic field component. The background magnetic field component is representative of a measurement error affecting the first magnetic field value. The two magnetic sensors may each be capable of sensing at least two, preferably three, components of a magnetic flux among the three x, y, z directions.

As shown in Figures 2 and 3, the cap 1 comprises two steel cover plates 3 screwed to the longitudinal side 25 of the body 2. The longitudinal side 25 is facing the rail 9 when the cap 1 is attached to the detector device 10. The longitudinal side 25 of the body holding the cover plates 3 may be referred to as the plate side. The cover plates 3 are mutually spaced along the longitudinal direction, or x axis, parallel to the rail 9, extend alongside of the recess 20. The cover plates 3 are distanced from each other in the same manner as the two magnets are distanced from each other along the longitudinal direction. The cover plates 3 are arranged so as to be respectively positioned between a respective magnet of the detector device 10 and the rail 9, and perpendicular to the lateral direction, or z axis, when the cap 1 is attached to the detector device 10. By positioning the cover plates 3 between the magnets of the detector device 10 and the rail 9, the cover plates 3 affect the magnetic field created by the magnets and simulate the presence of a wheel on the rail 9.

The sensed magnetic field values sensed by the two magnetic field sensors 11 and 12 are such that the signal provided by the processor in the detector device on the basis of the sensed magnetic field values indicates the presence of a wheel on the rail 9. Such a wheel detection signal is then typically wirelessly communicated (via a LoRa network or a GSM network) to a railway operator, forbidding trains from entering the area and enabling thus trackworkers to remain safely on or near the rail 9. The thickness of the cover plates 3 may be selected in accordance with the strength of the magnets of the detector device 10. Alternatively, the cap 1 may comprise a single cover plate when meant for other detector device with for instance a single magnetic field generating means, including axle counter having a single coil. Such detector devices/axle counters have been discussed in WO2021/004800, hereby incorporated by reference.

The cap 1 is movable onto the detector device 10 as illustrated in Figures 5 and 6, wherein the detector device 10 is received in the recess 20 of the cap 1, and the longitudinal side 25 of the cap 1 faces the rail 9, in particular faces an (inner) lateral side 90 of the web of the rail 9 (a detector device being typically installed in between rail tracks). In such a configuration, the body 2 of the cap Ì comes in mechanical contact with a housing of the detector device 10. The detector device 10 has housing with a top side substantially aligned with the horizontal surface 31 of the rail 2 and a sensing side 15 oriented parallel with the lateral side 90 of the rail track and at a distance thereof.

As the magnets have inverted pole orientations, they both attract the cover plates 3 when brought in proximity. A magnetic loop forms holding the cover plates strongly onto the magnets, In this way, the cap | is pulled towards the detector device 10 and an inner surface 27 of the body 2 is brought in mechanical contact with the sensing side 15 of the detector device 10. The inner surface 27 is parallel to the longitudinal side 25 holding the cover plates 3. The inner surface 27 may comprise openings though which the cover plates 3 are exposed. The cover plates 3 are attracted to the magnets. The magnetic force of the magnets ensures the secure fastening of the cap 1 onto the detector device 10.

As shown in the exploded view in Figure 3, the cap 1 further comprises a polyoxymethylene plate 5 screwed to the side 25 and covering the cover plates 3. The polyoxymethylene plate 5 is provided with, and covered by, an outer bumper layer 6 made of rubber, for enhanced safety during trackworkers operations around the detector device 10. By covering the wheel detector 10 wit the cap 1 and providing the plate side 25 of the cap 1 with the bumper layer 6, reduced risks of hard collisions between said detector device and objects in the vicinity that might magnetically interact with the magnetic field of the detector device 10 are achieved. This improves the safety for handling the detector device and the safety of the trackworkers.

The top 21 of the cap 1 is further provided with a handle 7 to facilitate placement of the cap | onto, and removal of the cap 1 from, the detector device 10 or the rail 9 and to facilitate sliding the cap 1 over the rail 9 for testing the detector device 10 as will be discussed with respect to Figures 7 and 8. The handle 7 extends in the longitudinal direction.

As shown in Figures 2-4, the cap 1 further comprises a magnet 8 integrated into the top 21 for generating a confirmation magnetic field to be sensed by the magnetic field sensor 11 of the detector device 10. Upon detection of the confirmation magnetic field generated by magnet 7, the processor in the detector device may provide a signal confirming the placement of the safety cap 1 onto the detector device 10. This signal may be further used to turn on AC field generating means in the wheel detection device 10 for transferring energy to an electromagnetic coil (not represented) in the safety cap 1. In return this received energy may power a light 30 on the safety cap 1. The light emitted by said light 30 is visible by a trackworker as a confirmation that the safety cap is correctly in place. Alternatively, the signal for turning on the AC field generating means may be triggered by the processor when a wheel is continuously detected during a given time period. The given time period may be selected to be indicative of a still standing wheel.

Optionally the cap 1 may comprise a testing plate 4. The purpose of the testing plate 4 will be discussed with respect to Figure 7 and 8. As illustrated in Figures 7 and 8, the cap 1 may be removable from the detector device 10 and movable onto the rail 9 as. In such a case, the rail 9 is received in the recess 20 of the cap 1 and the plate side 25 of the cap 1 now faces the detector device 10. The testing plate 4 is made of steel and screwed to the plate side 25 covering the cover plates 3. When the cap 1 is placed onto the rail 9, the test plate is positioned closer to the detector device 10 than the cover plates 3. This way, the cap 1 can be used as a testing device for testing the detector device 10. The front 23 and the rear 24 of the cap 1 are each formed as an inverted U- shaped guiding portion 230, 240 for guiding the cap 1 in a sliding movement over the rail 9 for translating the testing plate 4 past the detector device 10. When sliding the cap 1 over the rail 9 and translating the testing plate 4 past the detector device 10, magnetic field values are sensed by the magnetic field sensors of the detector device 10 and communicated to the processor, If the processor indicates a wheel detection signal during the translation of the cap 1, correct operation of the axle counter can be verified. Alternatively, the testing may be for calibration purposes of the detector device 10. To facilitate the sliding movement, each guiding portion 230, 240 comprises a guiding surface 231, 241 for engaging the rail 9 received in the recess 20, the guiding surfaces 231, 241 laterally engaging the rail 9 on the lateral sides of the head of the rail 9, such that the guiding surfaces 231, 241 prevent the cap | from being pulled towards the detector device 10 by the magnetic field.

The shown testing plate 4 is shaped as a disk segment to simulate a passing train wheel when sliding the cap 1 over the rail 9 past the detector device 10. Alternatively, the testing plate 4 may have a shape that does not correspond to part of the shape of a wheel, to enable differentiation between the testing plate 4 and an actual wheel on the rail 9. For instance, the testing plate 4 may have a shape that is substantially non-mirror-symmetric with respect to any plane perpendicular to the rail 9.

Whilst the principles of the invention have been set out above in connection with specific embodiments, it is understood that this description is merely made by way of example and not as a limitation of the scope of protection which is determined by the appended claims.

Claims

Conclusions

1. A method for working safely on or around a railway equipped with a wheel detection device, the wheel detection device comprising a magnetic field generating means that generates a magnetic field, at least one magnetic field sensor, each sensor measuring a respective magnetic field value, and a processor in communication with the at least one magnetic field sensor for detecting the passing of a wheel on a track of the railway based on at least one measured magnetic field value, the method comprising the steps of: - providing a safety device comprising at least one ferromagnetic plate adapted to imitate a wheel for the wheel detection device, and - placing the safety device on or near the wheel detection device.

A method according to claim 1, wherein bringing the security device onto or near the wheel detector device comprises attaching the security device to the wheel detector device, preferably as a cover device over the wheel detector device.

3. A method according to the preceding claim, wherein attaching the security device to the wheel detector device comprises magnetically attaching the security device to the detector device based on the magnetic attraction between the at least one ferromagnetic cover plate body and the magnetic field generating means.

4. A method according to at least one of the preceding method claims, wherein the method further comprises verifying the correct attachment of the security device to the wheel detection device via a light indicator.

5. A method according to at least one of the preceding method claims, wherein the detector device comprises an additional magnetic sensor for measuring an additional magnetic field value and wherein the security device comprises a magnet generating a confirmation magnetic field to be received by the additional magnetic sensor, the method further comprising confirming the presence of the security device on the wheel detector device when the measured additional magnetic field value equals the confirmation magnetic field.

6. A method according to at least one of the preceding claims, further comprising performing maintenance on the railway line and/or on the wheel detection device.

7. A method according to at least one of the preceding claims, further comprising placing the safety device on the track and moving the safety device over the track along the length of the track in front of the wheel detector device such that the ferromagnetic test plate body is moved between the wheel detector device and the track.

8. A method according to the preceding claim, wherein the method further comprises verifying whether the processor correspondingly generates a predetermined response associated with the security device.

9. Method according to at least one of the preceding claims 7 or 8, wherein the safety device comprises a ferromagnetic test plate body, and wherein the step of moving the safety device over the track along the lengthwise direction of the railway line in front of the wheel detection device comprises guiding the safety device using the guide members such that the ferromagnetic test plate body is translated past the at least one magnetic field sensor.

10. A safety device for a wheel detector device disposed adjacent to a railway, the wheel detector device comprising a magnetic field generating means for generating a magnetic field, at least one magnetic field sensor, each sensor measuring a respective magnetic field value, and a processor in communication with the at least one magnetic field sensor for detecting the passing of a wheel on a track of the railway based on at least one measured magnetic field value, the safety device being adapted to be releasably attached to or adjacent to the wheel detector device and comprising at least one ferromagnetic cover plate body simulating a wheel for the wheel detector device.

A security device according to the preceding claim, wherein the security device is adapted to be releasably attached to the wheel detector device, preferably as a cover over the wheel detector device, and wherein the at least one ferromagnetic cover plate body is positioned between the at least one magnetic field generating means and the track.

12. A security device according to at least one of the preceding device claims, wherein the at least one ferromagnetic cover plate body has a thickness selected to mimic a wheel to the processor.

13. A safety device according to at least one of the preceding device claims, wherein the magnetic field generating means comprises two magnets positioned at a distance along a lengthwise direction of the railway, and wherein the at least one ferromagnetic cover plate body comprises two ferromagnetic cover plate bodies positioned at a distance along a lengthwise direction of the railway, each associated with a respective magnet.

14. A security device according to at least one of the preceding device claims, wherein the security device is adapted to be releasably magnetically attached to the wheel detector device based on the magnetic attraction between the at least one ferromagnetic cover plate body and the magnetic field generating means.

A security device according to at least one of the preceding device claims, wherein the security device is adapted to be releasably attached to a measuring side portion of the housing of the wheel detector device containing the at least one magnetic field generating means and the magnetic field sensor, and wherein the security device comprises a body provided with a detector receiving recess configured to receive said measuring side portion of the housing for attaching the body to said measuring side portion of the housing, the at least one ferromagnetic cover plate body being attached to the body and extending along the detector receiving recess.

16. A security device as claimed in the preceding claim, wherein the detector receiving recess extends through a side of the body parallel to the side holding the at least one ferromagnetic cover plate body.

17. A security device according to at least one of the preceding device claims, wherein the security device is adapted to be releasably attached to the track, and wherein the security device comprises a body provided with a track receiving recess shaped to receive said track for attaching the body to the track, wherein the at least one ferromagnetic cover plate body is attached to the body and extends along the track receiving recess.

18. A security device as claimed in the preceding claim, wherein the track receiving recess extends through sides of the body that are parallel to a side holding the at least one ferromagnetic cover plate body.

19. Security device according to at least one of claims 15 or 16 in combination with at least one of claims 17 or 18, wherein the detector receiving recess and the track receiving recess form a common recess.

20. A security device according to at least one of the preceding device claims, further comprising a non-magnetic outer bumper layer, the outer bumper layer being arranged on a same side of the body as the ferromagnetic cover plate body is attached to, the outer bumper layer forming an outer surface of the security device.

21. A security device according to the preceding claim, wherein the non-magnetic outer bumper layer comprises an elastomer, preferably rubber.

22. A security device according to at least one of the preceding device claims, further comprising a ferromagnetic test plate body for testing the functioning of the detector device, said test plate body extending parallel to the cover plate body.

23. A security device according to the preceding claim, wherein the ferromagnetic test plate body is shaped as a disk segment.

A security device according to at least one of the preceding two claims, wherein the security device comprises a body to which the test plate body and the cover plate body are attached, said body further comprising at least a first guide portion adapted to guide the security device in a sliding motion along the track for translating the ferromagnetic test plate body past the magnetic field sensor.

25. A safety device as claimed in the preceding claim, wherein the body further comprises a second guide member spaced apart from the first guide member and adapted to guide the safety device in said sliding movement along the track.

26. A security device according to the preceding claim, wherein the first and second guide members are arranged on parallel sides of the body which are perpendicular to a side to which the ferromagnetic test plate body is attached.

27. A security device according to at least one of the preceding device claims, further comprising a handle for manipulating the security device, the handle preferably being arranged on a top surface of the security device, such that from above the security device is moved onto or away from the wheel detection device or the track.

28. A security device according to at least one of the preceding device claims, wherein the ferromagnetic cover plate body is made of steel.

29. A security device according to at least one of the preceding device claims, wherein the body is made of polyoxymethylene (POM).

30. A security device according to at least one of the preceding device claims, further comprising a lamp and an electromagnetic coil adapted to receive energy from the wheel detector device and thereby drive the lamp when the security device is mounted on the wheel detector device.

31. A security device according to at least one of the preceding device claims, further comprising a magnet generating a confirmation magnetic field to be received by the wheel detector device to confirm the presence of the security device on the wheel detector device.

32. A security device according to at least one of the preceding device claims, wherein the body is monolithic.

33. A wheel detector system comprising a wheel detector device for detecting a wheel on a railway, the wheel detector device being adapted to be disposed adjacent to the railway, the wheel detector device comprising magnetic field generating means for generating a magnetic field, at least one magnetic field sensor, each sensor measuring a respective magnetic field value, and a processor in communication with the at least one magnetic field sensor for detecting the passing of a wheel on a track of the railway based on the at least one measured magnetic field value, the system further comprising a safety device according to at least one of the preceding apparatus claims.

34. A system according to the preceding claim, wherein when the security device is arranged on the detector device, the security device is magnetically attached to the wheel detector device based on the magnetic attraction between the at least one ferromagnetic cover plate body and the magnetic field generating means.

35. A system according to claim 33 or 34, wherein the wheel detector device comprises a housing measuring side portion containing the magnetic field generating means and the magnetic field sensor, the security device comprising a body to which the ferromagnetic cover plate body is attached, the security device body having a detector receiving recess configured to receive said housing measuring side portion for attaching the body to said housing measuring side portion, the at least one ferromagnetic cover plate body extending along the detector receiving recess.