Combined Passive and Active Method and Systems to Detect and Measure Internal Flaws within Metal Rails

Abstract

This invention utilizes two sensing technologies in combination with or in isolation of an automated inspection vehicle to conduct inspections of internal rail flaws in steel railroad track. A vehicle equipped with X-radiation sensing is used as a secondary method to assess the deviations in magnetic fields that are sensed by a primary sensor consisting of a single or multiple magnetometers. The magnetometers sense changes in magnetic field that are correlated to the flaws inside the steel rail. The combination of technologies improves the probability to detect railroad flaws and offers the ability to accurately track and monitor flaws.

Claims

1. A track inspection device comprising: a self-powered autonomous rail vehicle; a guide shoe mounted to the rail vehicle and housing one or more passive magnetometers in an array, the guide shoe positioning the one or more passive magnetometers to measure a magnetic field within a rail while the rail vehicle operates at speeds greater than twenty miles an hour; one or more guide wheels within the guide shoe controlling a set off distance between the rail and the one or more passive magnetometers; one or more linear slides and bearings within the guide shoe to traverse rail joints or gaps in the rail while maintaining magnetometer set off distance; a radiation source mounted to the rail vehicle and deployable to one side of the rail; an x-ray detector plate mounted to the rail vehicle and deployable to a second side of the rail; a rail shielding mechanically linked with the detector plate to minimize backscatter radiation; a collimator deployable between the radiation source and the rail, the collimator positioned and sized to control radiation penetration of the head of the rail or the web of the rail or the base or the rail or a combination of parts of the rail; a 360 degree Light Detection and Ranging (LiDAR) system operable to detect obstructions and/or animals and/or humans within a radiation zone around the rail vehicle; a light and audio warning system operable during x-ray to illuminate and warn of a radiation zone; and a computer system on the rail vehicle, the computer system: receiving data from the one or more passive magnetometers; controlling speed of the rail vehicle; monitoring data from the one or more passive magnetometers to detect possible internal rail flaws based on the measured magnetic field exceeding a threshold variation, or rate of change variation, from one or more prior measurements at a same rail location or adjacent measurements along the rail; stopping the rail vehicle upon detection of a possible internal rail flaw; controlling deployment, positioning, and operation of the radiation source and x-ray detector plates after stopping the rail vehicle.

2. The track inspection device of claim 1, further comprising a second guide shoe with additional passive magnetometers to measure a magnetic field within a second rail.

3. A track inspection device comprising: a rail vehicle; one or more passive magnetometers in an array mounted to the rail vehicle; and a computer system on the rail vehicle, the computer system receiving data from the one or more passive magnetometers.

4. The track inspection device of claim 3, further comprising a guide shoe housing the one or more passive magnetometers, the guide shoe positioning the one or more passive magnetometers to measure a magnetic field within a rail while the rail vehicle operates at speeds greater than twenty miles an hour.

5. The track inspection device of claim 4, wherein the guide shoe fits around the rail to position magnetometer measurement of a head of the rail, a web of the rail, and a base of the rail.

6. The track inspection device of claim 4, wherein the guide shoe is positionable for magnetometer measurement of track fixtures in addition to the rail, including at least one of a frog, a switch, and a crossover.

7. The track inspection device of claim 4, wherein the guide shoe includes guide wheels controlling a set off distance between the rail and the one or more passive magnetometers.

8. The track inspection device of claim 7, wherein the guide shoe includes linear slides and bearings to traverse rail joints or gaps in the rail while maintaining magnetometer set off distance.

9. The track inspection device of claim 8, wherein the rail vehicle is a self-propelled autonomous vehicle.

10. The track inspection device of claim 9, further comprising an x-ray or ultrasound system deployable to validate if an internal rail flaw exists based on the measured magnetic field exceeding a threshold variation, or rate of change variation, from one or more prior measurements at a same rail location or adjacent measurements along the rail.

11. The track inspection device of claim 10, wherein the x-ray or ultrasound system is an x-ray system comprising: a radiation source mounted to the rail vehicle and deployable to one side of the rail; an x-ray detector plate mounted to the rail vehicle and deployable to a second side of the rail; and wherein the computer system controls deploying and operating the x-ray system.

12. A track inspection device comprising: a rail vehicle; a radiation source mounted to the rail vehicle and deployable to one side of a rail; an x-ray detector plate mounted to the rail vehicle and deployable to a second side of the rail; and a computer system on the rail vehicle, the computer system controlling deployment and operation of the radiation source and the x-ray detector plate.

13. The track inspection device of claim 12, further comprising a rail shielding mechanically linked with the detector plate to minimize backscatter radiation.

14. The track inspection device of claim 12, further comprising a second radiation source, a second detector plate, and a minimized rail shielding such that the computer system controls capture of simultaneous offset x-ray images.

15. The track inspection device of claim 13, further comprising a collimator deployable between the radiation source and the rail, the collimator positioned and sized to control radiation penetration of the head of the rail or the web of the rail or the base or the rail or a combination of parts of the rail.

16. The track inspection device of claim 15, further comprising a 360 degree Light Detection and Ranging (LiDAR) system in connection with the computer, wherein the LiDAR system is operable to detect obstructions and/or animals and/or humans within a radiation zone around the vehicle.

17. The track inspection device of claim 16, further comprising a light and audio warning system operable during x-ray to illuminate and warn of a radiation zone.

18. The track inspection device of claim 17, wherein the rail vehicle is a self-propelled autonomous vehicle.

19. The track inspection device of claim 18, further comprising one or more passive magnetometers in an array mounted to the rail vehicle and wherein the computer system receives data from the one or more passive magnetometers.

20. The track inspection device of claim 19, wherein the computer system controls speed of the rail vehicle, monitors data from the one or more passive magnetometers to detect possible internal rail flaws, stops the vehicle upon detection of a possible flaw, and positions for x-ray validation of the possible flaw after stopping the vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In the drawings, closely related figures and items have the same number but different alphabetic suffixes. Processes, states, statuses, and databases are named for their respective functions.

[0044] FIG. 1 is a diagram of the longitudinal and cross sections of a rail.

[0045] FIG. 2 is a system diagram of the major components of an internal track inspection system utilizing both magnetometer and x-radiation technology.

[0046] FIG. 3 depicts a series of three repeated magnetometer readings after a physical deformation in the rail with distance along the x-axis on the plot and the gauss reading on the y-axis of each plot.

[0047] FIG. 4 illustrates the detector plate and top of rail shielding attached to the vehicle chassis viewed from the outside of the vehicle.

[0048] FIG. 5 depicts the top of rail shielding viewed from the inside of the vehicle.

[0049] FIG. 6 depicts the x-radiation detector plate in relationship to the x-radiation source on a vehicle in a position where the detector is ready to image the head or web of the.

[0050] FIG. 7 depicts the x-radiation source in the lowered state in line with the detector plate viewed from the outside of the vehicle.

[0051] FIG. 8 depicts the x-radiation source inline with the detector plate and top of rail shielding, viewed from the inside of the vehicle.

[0052] FIG. 9 depicts the source, top of rail shielding, and detector plate, viewed along the longitudinal direction of the rail.

[0053] FIG. 10 depicts the underside of the magnetometer sensing sled that holds an array of magnetometers at a set distance above the top of the rail through the use of two roller wheels.

[0054] FIG. 11 depicts the magnetometer sensing sled on the top of the rail attached to the vehicle chassis.

[0055] FIG. 12 depicts the magnetometer sensor sled in relationship to vehicle chassis and x-radiation source and detector plate.

[0056] FIG. 13 illustrates the mechanical system that raises and lowers the magnetometer sled.

[0057] FIG. 14 is an isometric view depicting the geometry of the x-radiation source, collimator, rail, top of rail shielding, and detector plate.

[0058] FIG. 15 shows an offset view of FIG. 14 depicting the window in the collimator.

[0059] FIG. 16 depicts an example of a typical rail obstruction.

[0060] FIG. 17 shows a guide shoe retracted on one side and lowered on the other side to avoid the obstruction.

[0061] FIG. 18 depicts three primary assemblies of the alternative guide shoe shown in FIGS. 16-17.

DETAILED DESCRIPTION, INCLUDING THE PREFERRED EMBODIMENT

[0062] Terminology

[0063] The terminology and definitions of the prior art are not necessarily consistent with the terminology and definitions of the current disclosure. Where there is a conflict, the following definitions apply.

[0064] Field side—The side of the rail(s) pointing away from the track or the outside face.

[0065] Gauge side—The side of the rail which guides the wheel flange.

[0066] Parallel rails—One railroad track consists of two parallel rails. Standard gauge railroad track has two parallel rails that are separated by approximately 4 feet, 8.5 inches. Other railway gauges exist and may be greater than or less than standard gauge.

[0067] Railroad Track—Consists of two parallel rails, normally made of steel, secured to crossbeams called railroad ties or sleepers.

[0068] Frog—A crossing of point of two rails, usually as a common crossing or V-crossing.

[0069] This can be assembled out of several appropriately cut and bent pieces of rail or can be a single casting. A frog forms part of a railroad switch, and is may also be used in a level junction or flat crossing.

[0070] Joint Bar or Fish Plate—Typically a steel bar that joins two steel rails longitudinally using bolt holes and bolts.

[0071] Welded Joint or Continuously welded rail—A weld that physically bonds two rails together with no joint bar or other mechanical fixture.

[0072] Insulated Joint—Usually consisting of a joint bar, bolts, and holes that are mechanically connected but isolated by a non-conductive material such as rubber or plastic whereby two rails are physically connected but electrically isolated.

[0073] Flangeway—The general area on each side of the gauge side of the two generally parallel rails where railroad wheel flanges pass and aid in keeping train wheels within the lateral confines of the railroad track.

[0074] Set Off Distance—The pre-configured height or distance of a sensor from the target.

[0075] Source—The x-radiation emitter. Example sources include, but are not limited to, Golden Engineering's XR line of x-ray sources. The radiation is preferably generated through electrical emitting electrons to generate x-rays. However, it is not restricted to electron generated radiation, and may utilize gamma rays emitted by an atomic nucleus.

[0076] Detector plate—An x-radiation imaging plate that may utilize traditional film technologies or digital technology to capture the radiation from the source.

[0077] Operation

[0078] The following detailed description of the invention references the accompanying drawings which form a part hereof, and in which are shown, by way of illustration, specific embodiments which may be practiced. Understand that other embodiments may be used, and structural changes may be made without departing from the scope of the present disclosure.

[0079] Referring to FIG. 1, the head of the rail is 130. The web of the rail is 120. The base of the rail is 100. Internal flaws can exists in any section of the rail but are most common in the head of the rail. Flaws can be found in the transverse plane 140, horizontal plane 150, or vertical plane 160.

[0080] Referring also to FIG. 2, a preferred system embodiment includes a navigation and positioning system 200 that allows a mobile or robotic platform to move along a railroad track 270 whereby sensors capable of detecting changes in the magnetic field 280 in one or both of the rails of a railroad track. Referring also to FIG. 3, when the magnetic field exceeds a pre-defined tolerance measured in gauss or a rate of change 300, 310, 320 in gauss as computed by the vehicle mounted computing system 290, the robotic vehicle is commanded by the vehicle mounted computing system 290 to execute a more detailed internal flaw inspection using a x-radiation system 260. The pre-defined tolerance or rate of change may be set for an entire rail, or varied based on position of the rail allowing comparison with prior measurements at the same location, and vehicle mounted computing system may process, store, and analyze magnetometer data, or communicate wirelessly to send such data for remote storage and analysis. After the magnetometer sensor(s) 280 detects a potential flaw or magnetic change or magnetic field, the robotic platform is instructed by the vehicle mounted computing system 290 to re-position the vehicle using the navigation/positioning system 200 to align the x-ray source and detector plate 260 in the same location where the magnetometer(s) 280 detected a change or flaw in the rail. The 360 degree scanning LiDAR 230 determines if there are any obstructions, specifically humans or animals, that may be within the unsafe radiation zone that is defined by the light and audio warning 240 system. If an obstruction does exist within the unsafe radiation zone, the vehicle mounted computing system 290 prevents the x-radiation source from being activated. With no obstruction, the track sensors 220 providing lateral position distance from the rail are used by computing system 290 to laterally position the x-ray source and detector plate 260 in the raised state. If no obstruction continues to exist the radiation shielding 250 deploys to minimize any potential for back scatter x-radiation. After the shielding 250 is deployed in addition to the light and audio warning 240 and the vehicle is confirmed to be in the proper location by the navigation/positioning system 200 the x-radiation source and detector plate is lowered into position 260 in the proper geometry in relationship to the rail 270. When the source and detector plate are lowered and safety switches are fully engaged indicating proper positioning of shielding, source, and detector, the vehicle mounted computing system 290 enables power to the x-radiation source 260. At the completion of the imaging capture by x-ray radiation source 260, computing system 290 disables x-radiation power. After power is disabled, x-ray radiation source 260 and shielding 250 retract to avoid any obstacles in or around the track while the vehicle is in motion. Additionally, the light and audio are disabled whereby the vehicle mounted computing system 290 instructs navigation and positioning system 200 to continue movement along the railroad track while monitoring magnetometer sensor(s) 280. When magnetometer sensor(s) 280 identifies another flaw, the x-radiation system is re-deployed in the same manner as above. In addition, the x-radiation source 260 and related accessories may be deployed at set intervals or based on previously known locations such as rail welds identified by navigation and positioning system 200. In this case, the vehicle may use the magnetometer or alternatively just utilize the x-radiation system and related accessories to inspect the rail. The geometry of the detector plate in relationship to the source and the rail impacts the quality and ability of the system to detect or image flaws. Track sensors 220 provide lateral vehicle position information so that the source and detector plate 260 can be adjusted laterally in relationship to the rail so that proper geometry can be maintained during the inspection process.

[0081] Referring also to FIG. 3, the output generated by the magnetometer(s) is illustrated over a series of inspections over the same location on the rail whereby the flaw grew in size after each consecutive pass. Plot 300 shows the first pass of the magnetometer prior to the flaw being present. Plot 310 depicts a minor flaw being introduced to the rail, while Plot 320 depicts more severe damage to the rail after the flaw grew in size. Along the x-axis of each plot is the longitudinal distance along the rail. On the y-axis of each plot is the relative gauss reading. Referring also to FIG. 10, the combination of lines on each plot in FIG. 3 is from one individual magnetometer. Additional magnetometers may be arrayed as in magnetometer array 1010 to measure at multiple locations along the surface area of the rail.

[0082] Referring also to FIG. 4, when commanded by the navigation computer 200, the vehicle may stop to deploy the detector 440 and top of rail shielding plate 495. Detector 440 consists of an electronic or analog detector plate mounted in a supporting structure that moves on slides 480, powered by a motor 400 and gear system 470, into a lowered state along the top of the tie 410 or in parallel with the base of the rail 100. Upon a power failure, motor 400 and gear system 470 are back driven by strut 450. A top of rail shielding 495 plate may consist of lead or water to prevent over exposure of radiation on detector 440 allowing for improved imaging quality. In a similar manner as detector 440, shielding plate 495 moves into a lowered state by motor 400 via slides 480 as the top of rail shielding 495 is mechanically linked with detector 440. The combination of detector plate 440 and top of rail shielding 495 and the related structure are affixed to the vehicle chassis 490. In this depiction, the structure is mounted between two rail bound wheels 460 but may be positioned fore or aft of these wheels.

[0083] Referring also to FIG. 5, the top of rail shielding 495 is shown as viewed from the inside of the vehicle.

[0084] Referring also to FIG. 6, the x-radiation detector plate 630 is shown in relationship to the x-radiation source 685 on a vehicle 695 in a position where the detector is ready to image the head or web of the rail.

[0085] Referring also to FIG. 7, the source 685 is shown in the lowered state in line with detector plate 440 and top of rail shielding 495. The source uses a similar deployment method as the detector plate whereby motor 785 engages a drive sprocket to lower the source. At least one strut 795 raises the source upon power failure of motor 785. In addition to vertical movement, the source can be moved laterally to improve image quality via at least one track actuator 755. Referring also to FIG. 8, the source 685 is shown in line with the detector plate 440 and top of rail shielding 495. Plate 805 is interconnected with an internal limit switch that indicates the source has reached its lowest point. Top of rail shielding 495 may consist of a lead shot bag that is able to conform to the top of the rail 840. An internal contact switch encapsulated in detector plate housing850 indicates when the top of rail shielding is in position on the rail 840.

[0086] Referring also to FIG. 9, the view along the longitudinal direction of the rail depicts the source 685, top of rail shielding 495 and detector plate 440.

[0087] Referring also to FIG. 10, a magnetometer guide shoe 1020 is encapsulated in a non-ferrous material that consists of an array of magnetometers 1010. The guide wheels 1000 and 1040 can be adjusted within guide shoe 1020 to control the set off distance between the magnetometer array and the rail. Referring also to FIG. 11, the magnetometer shoe is capable of moving laterally as well as longitudinally along the length of rail as to prevent significant impact at a joint or some other obstruction through linear slides and bearings 1160, 1170, 1180, 1190, and 1195. The magnetometer shoe can be raised off the rail by retracting chain 1185. Referring also to FIG. 13, arm 1310 attached to motor 1300 counteracts the upward lifting force of strut 1320 that is connected to plate 1330 connected to the vehicle chassis. Strut 1320, upon a power failure in motor 1300 will retract the magnetometer shoe. In this configuration the magnetometer guide shoe is between the two vehicle wheels 1110 to help protect from damage by debris on the rail.

[0088] Referring also to FIGS. 14 and 15, depicts the geometry of the radiation source 685 is depicted in relationship to the collimator 1410, the rail 840, the top of rail shielding 495 and detector plate 440. The source 685 is set an approximate distance of 13 inches from the rail when the source is activated. The detector plate 440 may be positioned in direct contact with the field side of the rail or up to approximately 6 inches away from the rail. The purpose of the top of rail shielding 495 is to ensure that detector plate 440 does not become over saturated. Rail shielding 495 may consist of a fabric or flexible material that conforms to the shape of the top of the rail where the fabric or flexible material is filled with a radiation blocker such as lead or water. Collimator 1410 provides a small opening of approximately 54×75 millimeters and may be as small as 35×75 millimeters as shown in FIG. 15. The collimator opening may be fixed or automatically adjustable, and the opening and positioning allows radiation to penetrate and image the head, the web, or the base of the rail, or a combination of the parts of the rail at one time. The collimator 1410 may be positioned approximately 5 inches away from the source 685 and approximately 12.5 inches away from the rail. This geometry of source to rail to detector plate helps maximize quality of the capture image.

[0089] Referring also to FIGS. 16-18, an alternative guide shoe is able to position magnetometers into areas around the base and web of a rail without manual intervention, while also avoiding rail obstructions. Three primary assemblies enable the guide shoe to traverse a diversity of track fixtures such as a joint bars 1600 on either gauge or field side of the rail. Magnetometer shoe 1800 is the field side magnetometer shoe containing an array of magnetometers 1620. Magnetometer shoe 1800 is duplicated on the gauge side of the rail containing the same array of magnetometers as in array 1620. The magnetometer shoes are connected via an axle within a free wheel 1810 that rides along the top of the rail head. The axle is connected to a fixture that connects to the chassis of the vehicle (not shown). Magnetometer shoes 1800 and 1820 may be spring loaded in the down position or may be held down by gravity. A relatively narrow magnetometer shoe may, on the gauge side, ride within the flangeway of the railroad track. A typical obstruction such as a joint bar 1600, upon contact with flexible barrier 1610, results in magnetometer shoe 1800 pivoting around the axle within guide wheel 1810. The guide shoe may retract on one side and remain lowered on the other side. Both sides may be raised (not depicted) while the guide wheel 1810 remains in contact with the top of the rail. The guide shoe may be made out of consumable materials that have a high durometer so that they may contact the gauge and field side of the rail. Barrier 1610 may be made out of a combination of materials to allow for resilience to accept the repeated contact with joints and other track fasteners.

[0090] Other Embodiments

[0091] In addition to conducting inspections on railroad tracks already laid, the same technology may be used to assess and baseline rail as it first comes out of the manufacturing process. The baseline magnetometer or x-ray information may play an important part in the projection of where a potential flaw could grow and expand after installation in an operational environment. Additionally the baseline information may be used immediately after the manufacturing process and during the storage process to monitor the change in the rail and impact of environmental conditions on the rail during the storage process.

[0092] Multiple or smaller dedicated x-ray sources may be used to specifically focus x-radiation at multiple locations along the rail within the general confines of the inspection vehicle whereby offset imaging can be conducted at the same time using multiple sources and associated detector plate(s). These sources may be small enough to fit within the flange way of a railroad track minimizing the need to move, position, or adjust the x-ray source to target geometry. At the same time, the more focused energy results in less scatter and minimizes the need for heavy shielding to minimize radiation leakage. Multiple x-ray sources may be used to image both rails at the same time without the need to re-position or adjust the source.

[0093] As x-radiation sources become smaller and more focused in specific geometries, radiation imaging could be captured continuously while the inspection vehicle continues to move. Using Doppler shift techniques allows combination of many images to create a continuous image of the rail. This results in a more efficient inspection process and reduces the overall time needed to inspect.

[0094] Both magnetometers and x-ray technology is not only capable of sensing flaws in the two generally parallel rails of a railroad track, but the technology may be optimized to inspect other track fixtures such as frogs, gauge rods, points, bolts, tie spikes or tie fasteners, and other special track work associated with switches, crossovers, joints, etc. This may require robotic or automated re-positioning of the x-ray source and detector plate pair as well as the magnetometer sensors to achieve desired results.

[0095] Insulated joints may also be inspected using the x-ray system to ensure that the insulation gaps and related isolation material maintains proper spacing and overall electrical isolation between the two conductors.

[0096] The x-ray system to validate detected flaws may also be replaced with an ultrasound system for ultrasonic validation, or other imaging systems. In addition, the x-ray system may be deployed independent from the passive magnetometers, such as for use inspecting areas previously identified of concern, through manual local or remote operation, or in conjunction with other detection systems able to indicate possible flaws.

[0097] Understand that the above description is illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Determine the scope of the invention with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.