GB2443646A

GB2443646A - Inspecting railway tracks

Info

Publication number: GB2443646A
Application number: GB0622397A
Authority: GB
Inventors: William Davies
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-11-09
Filing date: 2006-11-09
Publication date: 2008-05-14
Also published as: GB0622397D0

Abstract

An automated system for inspecting sets of railway tracks for defects is mounted on a railway vehicle for travelling along a set of rails. The system includes a first acceleration sensor 2 measuring acceleration in a first direction and a second acceleration sensor 3 measuring acceleration in a second direction different from the first direction. The system also includes a location information module 12 (e.g. GPS, track-side transmitter) and a control device 7. The control device 7 receives acceleration measurements from the sensors 2, 3, associates these measurements with a track location determined by the location module 12. A property of the set of rails at a particular location is then determined. The system is mounted on a normal train rather than a specific inspection vehicle so that inspection can occur during normal operation of the railway network. The system may be used to detect faults in the train to which it is mounted.

Description

RAIL MEASUREMENT SYSTEM

This invention relates to a system and method for measuring properties of a rail or rails used in a transportation system. In particular, the present invention concerns a system and method for determining the condition of rails and other rail network components (such as sets of points) in a railway network used for the transportation of people and goods.

Inspection of railway tracks in a railway network is a time consuming and difficult process. Traditionally, the inspection of rails has been carried out manually by an engineer "walking the track" and visually inspecting the track for damage or wear. An engineer carrying out this process looks for signs that rails have become worn, that sleepers have cracked or rotten (in the case of wooden sleepers), that base plates or rail spikes have become loose or are missing, that fishplates or thermite or flash butt welds have become worn or have corroded, and other signs of wear, corrosion and damage to the rails and other rail network components.

Manual visual inspections are, however, time consuming and are subject to inevitable human error. Therefore, even a skilled engineer can miss signs of wear or damage, or poor construction, which can cause serious problems if left without maintenance or correction for a long period of operation.

The length of time required to inspect the rails visually and the need to operate most rail networks during the day has lead to a number of network operators employing engineers to carry out visual inspections of the rails during the hours when trains are not operating regularly on the rail network, such as at night. The lack of good light at night is an obvious hindrance for an engineer carrying out a visual inspection. In addition, fatigue is a key issue with engineers who must walk long distances to inspect large amounts of track in a single inspection period during the night.

In extreme examples, problems with the rails and rail network components can cause derailments and train crashes. The consequences of such incidents can be as minor as delays or as severe as cargo damage or passenger fatality. Thus, there is strong motivation for the development of an automated system which can inspect rails quickly without the need for manual visual inspections or in addition to manual visual inspections of the rail network.

Systems have been developed for the inspection of rails using ultrasonic signals applied to the surface of the rail in a direction either parallel to a longitudinal axis of the rail or perpendicular thereto. This type of inspection equipment can locate faults in the surface of the rail as well as having the capability to locate transverse rail faults even under shelling. Other systems for rail inspection include laser based systems for measuring the surface properties of the rail and even contact based systems in which a probe is contacted with the rail to determine surface properties of the rail. Eddy current based systems have also been proposed to probe deeper into the construction of rail and to act as a more reliable replacement for ultrasonic based systems.

The majority of automated systems which have been developed to inspect rails in a railway network are transported on the rails they are to inspect.

These systems often require dedicated engines to manoeuvre the inspection equipment at precise speeds in order to ensure accurate measurements of the rail. This means that it is not possible to use the section of the rail network being inspected for normal operation during an inspection period. Even though the automated equipment can perform an inspection sequence at a greater speed than an engineer performing a visual inspection, there are obvious advantages if the number of hours of inspection is kept to a minimum and the number of operating hours of a rail network is maximised.

The present invention seeks to ameliorate the aforementioned problems with the prior art by providing a system and method for inspecting rails in a railway network during normal operation thereof. The method and system of the present invention can be utilised instead of or in addition to the prior art rail inspection methods.

In order that the present invention may be more readily understood, embodiments thereof shall be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a diagram depicting an embodiment of the present invention; Figure 2 shows a diagram depicting another embodiment of the present invention; Figure 3 shows a diagram showing the communications network utilised by embodiments of the present invention; Embodiments of the present invention can be best described with reference to the figures; in particular, a simple form of an embodiment of the present invention is shown in figure 1 and a more complex form is shown in figure 2.

In its simplest form the present invention comprises a rail measurement system 1 comprising two or more acceleration sensors 2,3. The acceleration sensors 2,3 (having respective sensing directions) are arranged such that they are capable of measuring the acceleration in two different directions 4,5.

Preferably, the two different directions 4,5 are perpendicular to each other and in a single plane or in parallel planes (usually the plane or planes are perpendicular to the general direction of travel).

For simplicity the orientation of a first acceleration sensor 2 shall be assumed to be such that it is capable of measuring acceleration in a vertical direction 4 and the orientation of a second acceleration sensor 3 shall be assumed to be such that it is capable of measuring acceleration in a horizontal direction 5.

However, it will be appreciated that this specific orientation is merely one example of many possible orientation combinations and that more than just two sensors can be utilised.

The acceleration sensors 2,3 may comprise, for example, Piezo electric acceleration sensors, or micorelectromechanical sensors (MEMS) or a combination of one or more types of sensor.

The two acceleration sensors 2,3 are each connected to an analogue to digital converter (ADC) 6 which selectively converts the analogue output signal from the sensors (ie. the ADC 6 may select which of the sensor outputs to convert) into a digital numbers representative of the analogue output. In alternative embodiments, each sensor has an ADC 6; future references to an ADC 6 should be construed as including references to two or more ADCs shared or individually used by two or more sensors. In further embodiments, the ADC 6 forms part of the sensors 2,3 themselves.

The output from the ADC 6 is connected to a control device 7 (such as a microprocessor or microcontroller) which is operable to receive the output of the ADC 6 and store the output data in a memory element 8. The memory element 8 may comprise either volatile or non-volatile memory.

A timing module 9 is also connected to the control device 7 (or may form part of the control device). The timing module 9 is able to maintain a record of the current time and date. Preferably, the timing module 9 is operable to maintain a record of the time to a resolution of 1 jis, ins or 1 ms.

In some embodiments the control device 7 is operable to store the output from the ADC 6 in the memory element 8 (at a sample time) along with one or more timestamps (the values of which are determined by the timing module 9). In other embodiments an initial "start" timestamp is stored in the memory element 8 when the system begins operation; the stored ADC output data values are sequentially stored at regular sample times such that the time of any particular data value can be calculated by using the start timestamp and the number of data values that precede the value in question along with the sample time.

It wit I be appreciated that the data values stored in the memory element 8 will come from at least two different acceleration sensors 2,3. Thus, there must be some way of differentiating a stored data value from, for example, the first sensor 2 from a value from the second sensor 3. This can be achieved in a number of different manners: the sensors 2,3 could be sampled sequentially such that the data stored in the memory element 8 may be sequentially matched to the sensor 2,3 from which the value was obtained; alternatively, the memory element 8 could be separated by two or more respective partitions each partition defining separate areas of storage which may be used in relation to a respective sensor 2,3 (thus, each separate storage area only stores data values from one sensor 2,3); or each data value could be stored with an additional sensor identifier such that it is possible to identify the source of the data value by studying the identifier associated with that data value.

The advantages and disadvantages of each of these methods are apparent and the selection of which method to utilise will depend upon a number of factors including the arrangement of the rest of the system and the size of the memory element 8.

In embodiments in which there is more than one ADC 6, the ADC may include a latch element (not shown) to store the digital output of the ADC 6 such that the control device 7 can obtain data values for two or more of the acceleration sensors 2,3 at one point in time (rather than sequentially wherein the data values are gathered at different times).

In some embodiments of the present invention the control device 7 is also connected to a Global Positioning Satellite (GPS) receiver (or an equivalent -such as the Inertial Navigation System (INS)). The GPS receiver is operable to record the location of the system 1 and output location information to the control device 7 which may store this information in the memory element 8.

Preferably, any location information which is obtained from the GPS receiver corresponds to the location of the system at the sample time when a respective data value from one or more of the sensors was obtained and stored in the memory element 8. The location information may be obtained (and stored) in respect of every data value from the ADC 6 which is stored in the memory element 8 or the location information may be obtained (and stored) at predetermined time intervals.

In some embodiments of the present invention the control device 7 is also connected to a short range communications channel receiver. The short range communications channel receiver is operable to receive short range signals which include an identifier. This identifier may be stored by the control device 7 in the memory element 8 in conjunction with a respective data value from the ADC 6. Thus, local transmitters (each with a different identifier signal) can be placed along a path of travel of the system 1; when a signal from a local transmitter is received, the identifier of that transmitter is stored and the location of the system I at that time can be determined by studying the information in the storage element 8.

The GPS receiver and short range communications channel receiver are examples of location information modules 12 The system 1 further comprises one or more output arrangements 10 which may comprise one of more of the following: an output interface connector, a radio frequency transmitter, a microwave frequency transmitter, an infrared transmitter, or an electromagnetic transmitter. The one or more output arrangements may be suitable for communication with other elements to form a communications network as depicted in figure 3.

The purpose of the one or more output arrangements 10 is to allow a user to retrieve the information stored in the storage element and to provide the system 1 with instructions (which are stored in the memory element 8 or in a separate memory element 11 which is preferably non-volatile memory).

It will be understood that the system 1 may be used to measure its own acceleration in two or more directions (ie. in the vertical and horizontal directions in the example given above). The sensors 2,3 of the system 1 can be arranged in a number of different configurations in order to achieve this effect. In addition, two sensors may be arranged to measure acceleration in the same direction. This can provide a redundancy feature which ensures that the system 1 requires little maintenance or the outputs from the two sensors in the same arrangement can be compared to determine another characteristic of the acceleration of the system (for example, roll).

It will be appreciated that in some circumstances it is, therefore, preferable to separate the two or more sensors 2,3 from each other. Thus, the system I may be contained within a series of boxes or other units with the control device 7 and other system components (such as the location information module 12, output arrangement and memory element 8) being contained in one or other box units and the sensors 2,3 being contained in one or more boxes or other units separated from the control device 7 and linked to the control device 7 or ADC 6 by a wired or wireless connection (not shown).

The system 1 may be used for rail inspection in a rail network by placing the system on a train which operates on the rail network. Preferably, the train is a normal train which operates at normal operational speeds during the normal operation periods of the rail network. Thus, it will be understood that the present invention may be used during the normal operating period of a railway network with no disruption to the operation of the network.

The sensors 2,3 must be securely attached to, for example, the train (or other railway vehicle) with which they are intended to be operated. Alternatively, the sensors 2,3 could be securely attached to another part of the system I which is, itself, securely attached to, for example, the train. The attachment may be achieved through the use of an attachment arrangement such as an adhesive, or one or more nuts and bolts.

The system 1 is advantageously secured to, for example a passenger train, away from the floor of the passenger train to avoid the movements of passengers causing unwanted noise in the sensor outputs during the operation of the system 1.

When in operation on a train, the system is operable to store the data values representing the acceleration of the train in different directions as the train travels along the track. It will be appreciated that it will, therefore, be possible to study the condition of the rails and components of the rail network by identifying areas of the track in which large or rapid accelerations are recorded. The area of the track can be determined by reference to the location information obtained from the location information module 12 or simply from the timing module 9 information stored in the memory element 8.

It will be appreciated that a train will accelerate in the direction of travel in some areas and decelerate in the direction of travel in other areas. Thus, the system 1 preferably has sensors 2,3 which are orientated such that this deceleration and acceleration does not have a substantial effect upon the sensor outputs (ie. the sensors 2,3 are in one plane which is perpendicular to the direction of travel). Alternatively, one or more of the sensors 2,3 could be used to evaluate the acceleration and deceleration in the direction of travel to review the train driver's operating practice and, for example, the effects of speed limit changes along a rail track on the comfort of passengers.

The system 1 may store the recorded information between periodic inspections of the system 1 by an engineer. During such inspections the engineer may retrieve the information stored in the memory element 8, delete information stored therein, retrieve or alter the program which controls the operation of the control device 7, or repair or replace any of the components of the system 1. Preferably, the system 1 has modular components which may be removed and replaced with little difficulty.

Alternatively, the system 1 may transmit the information stored in the memory element 8 (or even receive changes to the program which controls the operation of the control device) through the output arrangement 10 automatically, continuously, at periodic intervals, or at predetermined locations. The information may be transmitted using at least one of the one or more output arrangements 10 to a base station 13 which is, in turn, connected to a monitoring station 14.

The information retrieved from the memory element 8 can be represented on a map (for example, on a computer at the monitoring station 14). The map can include indications of the location of rail network components such as the location of joints between rails (along with, for example, an indication of the type of joint and/or the last time the joint was replaced or repaired). The information from more than one system 1 may be represented on the map; thus, a user will be able to determine areas or interest which may need repair or further investigation and disregard areas in which large accelerations occur but where the accelerations can be explained by other factors (such as the location of a set of points). Preferably, the acceleration information is displayed on the map as a line whose width varies depending upon the magnitude of the total acceleration recorded at that point.

In some embodiments of the invention, the information from the system 1 is recorded and railway track areas in which large or rapid accelerations occur are identified. An engineer will subsequently inspect these track areas and determine the cause of the large or rapid accelerations which were recorded.

The engineer may record the cause in a computer system along with the data values representing the measured accelerations at the relevant areas of the track. Thus, in the future, the computer system can be programmed to recognise a particular type of track problem based solely upon the acceleration data values from the system 1 (by using the old data values and recorded track problems to calibrate the recognition system).

It will be appreciated that the present invention may be utilised to locate a large number of different types of fault on a set of rails. In addition, the present invention could also be used to detect faults with the railway vehicle to which it is attached (for example, worn wheels or damaged brakes).

In embodiments of the present invention, the system 1 is operable to detect one or more data values of interest by comparing the values with predetermined threshold values. When one or more values of interest are identified they may be marked as an event. The marking of an event may cause the system 1 to output a signal from the one or more output arrangements 10 to draw the event to the attention of a user. The signal may include the one or more data values associated with the marked event.

When used in this Specification and Claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following Claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS: 1. A measurement system for attachment to a railway vehicle

suitable for travel along a set of rails, the system comprising: a first acceleration sensor operable to measure acceleration of the sensor in a first direction and output a first data value representative of the measured acceleration to a control device; a second acceleration sensor operable to measure acceleration of the sensor in a second direction and output a second data value representative of the measured acceleration to the control device, the first and second directions being different from one another; and a location information module connected to the control device, the control device operating to receive the outputs from the sensors and associate the outputs with a location determined by the location information module, so that a property of the set of rails at a particular location can be determined using the first and second data values.
2. A system according to claim 1, wherein the first and second directions are perpendicular to each other.
3. A system according to claim 2, wherein the first and second direction lie in a plane perpendicular to a direction of travel of the railway vehicle.
4. A system according to any preceding claim, further comprising a memory element suitable to store the first and second data values and their associated locations.
5. A system according to any preceding claim, wherein further data values are output by each of the acceleration sensors over a period of time.
6. A system according to any preceding claim further comprising additional acceleration sensors each capable of outputting respective data values to the control device.
7. A system according to any preceding claim, wherein the control device is connected to a monitoring station which is operable to analyse the outputs from the sensors to identify a property of the set of rails of a particular location based upon the data values.
8. A system according to any preceding claim, wherein the data values are compared with one or more predetermined threshold values in order to determine a property of the set of rails or to identify an event.
9. A method of determining a property of a set of rails comprising: providing a control device, first and second acceleration sensors in a railway vehicle suitable for travel along the set of rails, and a location information module connected to the control device; measuring the acceleration of the first sensor in an first direction; outputting a first data value to the control device representative of the measured acceleration in the first direction; measuring the acceleration of the second sensor in a second direction; outputting a second data value to the control device representative of the measured acceleration in the second direction, the first and second directions being different from one another; receiving the outputs from the sensors at the control device; and associating the outputs from the sensors with a location determined by the location information module, so that a property of the set of rails at a particular location can be determined using the first and second data values.
10. A method according to claim 9, further comprising orientating the sensors such that the first and second directions are perpendicular to each other.
11. A method according to claim 10, wherein the first and second directions lie in a plane perpendicular to a direction of travel of the railway vehicle.
12. A method according to any one of claim 9 to 11, further comprising providing a memory element suitable to store the first and second data values and their associated locations.
13. A method according to any one of claim 9 to 12, further comprising the outputting of further data values by each of the acceleration sensors over a period of time.
14. A method according to any one of claim 9 to 13, further comprising providing additional acceleration sensors each capable of outputting respective data values to the control device.
15. A method according to any one of claim 9 to 114, further comprising connecting the control device to a monitoring station which is operable to analyse the outputs from the sensors to identify a property of the set of rails at a particular location based upon the data values.
16. A method according to any one of claim 9 to 15, further comprising comparing the data values with one or more predetermined threshold values in order to determine a property of the set of rails or to identify an event.
17. A method as herein described with reference to the accompanying figures.
18. A system as herein described with reference to the accompanying figures.
19. Any novel feature or combination of features described herein.