GB2593767A

GB2593767A - Surface condition monitoring of railway tracks

Info

Publication number: GB2593767A
Application number: GB2004903.7A
Authority: GB
Inventors: Francis Ralph Swan Julian; Spencer Jaynes Candy Matthew
Original assignee: Imagination Factory Ltd
Current assignee: Imagination Factory Ltd
Priority date: 2020-04-02
Filing date: 2020-04-02
Publication date: 2021-10-06
Also published as: GB2593825B; EP4126632A1; GB2593825A; US20230192160A1; WO2021198713A1; CA3174257A1; CN115916621A; AU2021246970A1; JP2023522157A; GB202104894D0; GB202004903D0

Abstract

A device 1 for monitoring the condition of the surface of railway track rails 2, comprises a spectrometer configured to monitor at least one frequency corresponding that indicates the presence of a contaminant on a railway track rail and to provides an output indicative of the presence or absence of the contaminant on a railway track rail 2. The spectrometer may monitor a plurality of frequencies, and/or be a Ramen spectrometer. The device may be handheld, or mounted alongside a track, potentially for monitoring a plurality of rails. A surface conditioning device may act in response to data received from the monitoring device. The surface conditioning may be by a plasma delivered to the rail.

Description

SURFACE CONDITION MONITORING OF RAILWAY TRACKS

This invention pertains generally to the field of surface monitoring, and in particular surface condition monitoring devices for use on railway track rails to help monitor and maintain the optimum condition of rail to wheel interface.

The surface condition of railway tracks presents a real challenge to rail network operators who must ensure that they are well maintained and kept in optimum condition for the passage of rail vehicles. The railway track rails, typically made from steel, are subjected to considerable forces from passing vehicles that can cause surface and structural wear, whilst also being exposed to adverse and frequently changeable weather conditions, along with other environmental hazards throughout the year. '1 he rail to wheel interface, typically steel against steel, provides an energy efficient combination, yet this interface ca.n prove to be highly sensitive to contamination. Precipitation, dew, leaf fall, localised temperature changes, extreme weather conditions, vegetation and other detritus, are just some of the events that ca.n affect the surface condition of the rail track, and therefore the passage of the rail vehicle passing thereon. The majority of these contaminants have significant water content, which affects adhesion of the wheel on the rail surface.

Contaminants can be referred to as a 'third layer' between first and second layers which are respectively the railway track rail and the railway vehicle wheel, or vice versa.

The smooth, safe and efficient running of a rail vehicle relics upon die friction between the steel rails and the steel wheels. Fundamental to predictable and optimised braking of a rail vehicle using conventional brakes, is creating a 25 reliable rail to wheel interface that has sufficient friction for the desired rate of -2 -deceleration. Friction can be reduced when the rails become slippery or greasy, often because of rain, dew, fluids such as oil or even decomposing leaves that fall onto the line and can become compacted. This can result in a chemical reaction occurring between the water soluble leaf component and steel rail coating. This coating is semi-permanent and therefore it may take time to be sufficiently worn awa.y by the passage of trains. Such variance and unpredictability to surface conditions of the mil tracks in terms of moisture and detritus can present a real challenge to network operators. They must predict the likelihood of low friction conditions being experienced by a passing vehicle, causing the vehicle to slip, before this happens, and take steps to minimise the impact. 't they must carry out ongoing monitoring of track conditions to flag up areas of concern and again take steps to rectify these. they must ensure that trains are adequately spaced along the line to ensure that required stopping distances are taken into account in light of changeable surface conditions. With such conditions subject to change at any moment, particularly environmental conditions due to changeable weather, it is very common for issues to occur. Rail network operators are quick to delay or cancel trains, rather than risk passenger safety. 'timetables are often altered for different seasons, such as in the UK, regular Autumnal timetabling takes steps to anticipate these delays during the leaf fall season. This comes at considerable cost to the rail industry. Tt was estimated that leaves on the line cost around f60milliou in direct costs each yea.r in the UK alone, which is estimated to amount to around 1,350million societal costs.

A loss of friction at die rail to wheel interface effects traction when the train first sets off and starts moving, which in the case of freight trains, affects hauling capability. '1 he wheels can be caused to spin, and in some instances the train is unable to move. These low friction conditions result in poor adhesion between the wheel to rail interface, also causing issues when braking and coming to a stop. Substantial loss of friction results in reduced braking forces, meaning -3 -that stopping distances are considerably longer and tins must be accounted for when dispatching trains within the rail network. In extreme cases the wheels may even lock, causing the train to go into a slide. This can cause considerable damage to the wheel and rail track. Station platforms may also be overshot where a driver has not allowed a sufficient distance to bring the train to a standstill.

Snow and ice, when deposited on rail tracks, can cause such low adhesion conditions to occur, making rail vehicles prone to slide (Jr slip during braking, whilst also causing the train to encounter difficulties pulling away. But less obvious conditions such as light rain following a spell of dry weather, or morning dew on the rails, can also cause challenging rail conditions for the rail networks to account for. 't he effect on the surface condition of the rail tracks may only be short term, but the unpredictable nature of such effects may be sufficient for a significant incident to occur to a passing rail vehicle. Tests have shown that there is a strong correlation between low adhesion incidents and the occurrence of the dew point, where water vapour from the air condenses onto the railhead fining a fluid film This fluid film leads to a loss of traction at the wheel to rail interface.

Other contributing factors are thought to include the move from brake shoes to disc brakes, which means that sonic surface cleaning and conditioning of the rails no longer occurs by abrasion. It is also thought that rail network operators no longer have to carry out sufficient lineside maintenance that would have been essential during the steam locomotive era, to prevent vegetation from catching fire. The extra growth from vegetation increases the supply of leaves and the increase of leaf fall onto the line, thereby exacerbating the problem. It may also affect the dew point and localised climate in some areas. In extreme cases, the build-up of leaf matter can electrically insulate the wheels from the -4 -rails, result* in signal failure. This can cause an event such as Wrong Side track Circuit Failure, or WSICE, when leaf matter electrically insulates the wheels from the rails resulting in signal failure. Other events such as Signal Passed at Danger, or SPAD, can also occur when a train slides past a signal because it could not stop.

Rail vehicles are typically fitted with wheel slide protection, in an attempt to counter slippers, rail conditions. When wheels become locked, flat spots can be ground into the steel rims, especially if the wheel is still sliding when entering a non-slippery portion of rail track. This can cause wheel flats, where the wheel shape has been altered from its original profile, leading to severe vibrations and die need for reprofiling of the wheels, or even wheel replacement, at considerable expense.

Numerous different ways of surface conditioning the rail tracks to deal with such changeable circumstances have been tried, and many are in operation.

These range from applying a jet to blast away any deposits or detritus, such as with water jets alongside a mechanical scrubbing apparatus of some form. Laser blasting the rails has also been tried and tested. Or coating the rail tracks and/or wheels with a high friction material, such as by depositing sand a.s a paste or otherwise, or die application of adhesion modifying chemicals, onto the rail.

The sand assists adhesion during braking and acceleration. However, using sand may increase die risk of unwanted insulation, and therefore may also contain metal particles. For an example, an adhesion modifier such as SanditeTM, combination of sand, aluminium particles and adhesive Btisting or coating die rails with sand and substances such as SanditeTM is not thought to offer an economically sound solution, nor is it thought to be environmentally friendly to release these substances into the environment. Alternative coatings currently in use include Track Grip 60Tm (TG60Tm) an adhesion enhancer for rails, or -5 -Electragel, which consists of steel particles and sand, suspended in a gel. To attempt to combat the issues experienced by moisture and the formation of dew on the rail tracks, and thereby improve both traction and impedance properties, the rails have typically been treated with hydrophobic products. To apply these coating or treatments to the rail tracks typically requires special trains or rail vehicles, and may also involve manual or application by hand. In the UK these vehicles typically include Rail IIead Treatment Trains or MITTs, or Multi-Purpose Vehicles or A4PVs. Again, a. challenge for the rail network operators to factor into the overall operation of the network, ensuring die passage of such rail 1 0 vehicles, or the application of such coating and substances at times when the track is not in use.

At specific sites, or portion of rail track, where significant low adhesion regularly occurs, such as on the approach to a station, traction gel applicators may have been installed. These apply liquid to the railhead as a rail vehicle 15 passes there through.

These processes are only effective for a short period of time. Jet blasting the rail track is ineffective as soon as the next leaf falls, or is deposited onto the rails due to the aerodynamic turbulence of a passing train, or other detritus lands along the line. Sand and other treatment products deposited directly onto the rail track or railhead may prove more durable, but these substances can be easily washed away by rainfall.

For the majority of these surface conditioning processes, the initial decision to condition the surface is made speculatively, and largely based on sight. An operator takes a look at a stretch of track, or makes a. decision based 25 on recent or imminent environmental conditions. Alternatively, a track is -6 -conditioned at predetermined intervals regardless of any specific indicator that a portion of track has reached a poor level.

file prior art shows a number of devices which attempt to address these needs in various ways.

GB 2 355 702 (LaserThor Ltd) discloses a method of cleaning a rail by removing contaminants from die surface of the rail. The method comprises the steps of generating a high intensity pulsed laser beam and directing the laser beam onto the surface of the rail so as to destroy at least part of the contaminants. The laser beam may be operated in response to detection of the contaminants. This control system comprises a light source and a tube which directs a light beam from the source to the surface of the rail, where the beam is reflected. A further tube collects the reflected beam and passes it to a prism which forms part of a spectrometer. The identity of many substances, such as leaves or other contaminants, can be determined by the analysis of the wavelengths of the light in a composite beam reflected off the surface of an object made from the substance by using a spectrometer. The control unit determines the nature of the substance from which the light beam has been reflected. Whilst providing a. means of determining a type of contamination on a rail surface, this arrangement presents accuracy issues and a considerable amount of sensing noise that leads to unclear results. Tt is also somewhat limited to the range of contaminants or materials that it is able to detect.

Whilst the prior art attempts to address flit issue of detecting the presence of various contaminants on a rail track, and therefore monitoring die condition of a portion of track, it does not deliver an accurate and clear result.

Whilst the prior art also attempts to determine the composition of any contaminants on the track, it does not provide means to accurately identify a -7 -broad range of materials, and thoroughly analyse the composition of these. The prior art addresses the issue of detecting predetermined contaminants, but it does not address the issue of monitoring their removal.

Preferred embodiments of the present invention aim to provide a surface monitoring device for monitoring the surface of rail track rails, to detect the presence of any contaminants on the rail track rail, to analyse the composition of these contaminants, and to monitor the outcome of any surface conditioning process, by analysing a. change in result.

According to one aspect of the present invention, there is provided a device for monitoring the condition of the surface of railway track rails, the device comprising a spectrometer configured to monitor at least one frequency that indicates the presence of a. contaminant on a railwa.y track rail a.nd to provide an output indicative of the presence or absence of the contaminant on a railway track rail.

Preferably, the spectrometer may be configured to monitor a plurality of frequencies that indicate the presence of contaminants on a railway track rail.

Preferably, the spectrometer may be a Raman spectrometer. The monitoring device may comprise a handheld device.

Alternatively, the monitoring device may be mounted alongside and 20 directed at a railway track rail and operative to provide an output indicative of the presence or absence of contaminants on the rail. -8 -

The monitoring device may be mounted alongside and directed at a plurality of railway track rails and operative to provide an output indicative of die presence or absence of contaminants on the rails.

The contaminants to be monitored may comprise at least one from die 5 group consisting of Cellulose, Cellulose Acetate and 'tyrosine.

The frequencies may have a wavenumber selected from the group comprising 640, 1430, 1480, 1260, 1213, 1240, 1580, 2000 cm-1.

Preferably, the device may be configured to compare a monitored value with one or more predetermined values and to provide a corresponding device 10 output that indicates whether the condition of a monitored railway track rail is above or below a predetermined acceptable level.

The Raman spectrometer output may be indicative of both type and amount of contaminant.

the monitoring device may comprise an operating interface whereby a 15 user can control operation of the monitoring device.

the monitoring device may be in combination with a surface conditioning device for railway track rails, the surface conditioning device being operative to condition die surface of one or more railway track rail in response to data received from the monitoring device.

2 0 The surface conditioning device may be operative to condition a railway track rail by means of plasma delivered to the rail. -9 -

According to a further aspect of the present invention, there is provided a railway vehicle with at least one monitoring device or combination as hereinbefore described.

The railway vehicle may comprise a driver's cab that receives an output 5 from said at least one monitoring device.

The railway vehicle may comprise at least two of said monitoring devices at spaced locations along the vehicle or along a train that is driven by the vehicle.

According to yet a further aspect of the present invention, there is provided a method of monitoring the condition of the surface of a railway track rail, the method comprising operating a. monitoring device as hereinbefore described to indicate the presence of contaminants on the rail and to provide an output indicative of the presence or absence of contaminants on the rail.

The method may comprise the further step of operating a surface conditioning device to condition the surface of the rail in response to data 15 received from the monitoring device.

The method may be carried out on a railway vehicle as it travels along the railway track rail.

The method may be carried out as the railway vehicle makes multiple passes along the railway track rail.

2 0 For a. better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: -10 -Figure 1 shows one embodiment of surface monitoring device as a handheld device, in use, monitoring the surface condition of a rail, with enlarged view of the handheld device; Figure 2 shows a further embodiment of surface monitoring device mounted track side, showing a pair of devices, in use, monitoring the condition of a rail, with enlarged side view of one of the track side devices; Figure 3 shows one embodiment of surface monitoring device when mounted to a railwa.y vehicle, showing a surface monitoring device mounted at the front of the vehicle, and a further surface monitoring device mounted at the 10 rea.r of the railway vehicle, with surface conditioning device between; Figure 4 shows a further embodiment of surface monitoring device when mounted to a locomotive, with enlarged view of the undercarriage of the locomotive; and Figure 5 shows one embodiment of surface monitoring device as a 15 schematic diagram, showing the component parts that allow the surface monitoring device to detect die presence of a material on a surface, and analyse the composition of the material on that surface.

In the figures, like references denote like or corresponding parts.

It is to be understood that the various features that are described in the following and/or illustrated in the drawings are preferred but not essential Combinations of features described and/or illustrated are not considered to be the only possible combinations. Unless stated to the contrary, individual features may be omitted, varied or combined in different combinations, where practical.

Figure 1 shows one embodiment of surface monitoring device 1, in use by an operator, typically a Mobile Operations Manager (MOM), to monitor the surface condition of an area of rail 2 A Mobile Operations Manager is the person responsible for checking rail track condition. They decide when to clean the rail track and confirm that the track is at a suitable level for normal operation.

The surface monitoring device 1 is a handheld device 6, and is portable, and easy to for the operator to carry about for measuring different surfa.ces. Figure 1 shows the handheld device 6 being held against or close to the surface of the rail 2, and also shows an enlarged view or close up of the handheld device 6. This shows one possible configuration of operating interface 4, that controls spectrometer 3, to take a reading of the rail 2. 't he handheld device 6 may be configured to detect and analyse a specific combination of contaminants on the surface, or it may store this data for later download and analysis. Alternatively, die handheld device 6 may \\Tirelessly transmit this data to a base station, not shown, to allow a central resource to analyse rail conditions throughout a network, and send out various surface cleaning and conditioning devices in response to this data.

Figure 2 shows another embodiment of surface monitoring device 1, where the device is incorporated into a pillar, mounted by the side of a. railway track, for monitoring a portion of rail 2. A spectrometer 3 shown in such an arrangement is transmittimi recorded data back to a central resource through transmitter 19. The enlarged view of one of these surface monitoring devices 1 shows that one device can be arranged to monitor the condition of two rails 2 at the same time, or as and when required. A monochromatic light source 8, such as a. laser, transmits a laser beam in the direction of the rail 2 on one side of the track, and a further monochromatic light source 8, transmits a laser beam to -12 -bounce off the rail 2 on the other side of the track, thus monitoring both rails 2 at the same time 'these surface monitoring devices 1 may be positioned at predetermined intervals along a railway line, sufficient to cover the majority of rails 2 within a network, or may be installed hi areas where surface condition of the rails 2 is of a particular concern.

Figure 3 shows yet a further embodiment of surface monitoring device 1 when mounted to the undercarriage of a railway vehicle 17. In this particular railway vehicle 17, there is a surface monitoring device 1 at the front end of the railway vehicle 17, and a further surface monitoring device 1 towards die rear of the railway vehicle 17. Mounted somewhere between these surface monitoring devices 1 is a surface conditioning device 5. The arrangement of both front and rear surface monitoring devices 1 allows an operator to determine the effectiveness of the surface conditioning device 5. There may be any number of surface monitoring devices 1 mounted along a railway vehicle 17, and configured to act upon the rails 2 along which the railway vehicle 17 is passing. There may also be any number of surface conditioning devices 5, to surface condition a section of rail 2 as many times as is required to achieve a suitable reading of surface condition by the last surface monitoring device 1.

t he surface conditioning device 3 ihi such an arrangement may comprise any number of different ways of conditioning the surface, such as jet blasting with water alongside mechanical scrubbing apparatus, laser blasting applying a coating of high friction material, depositing sand or applying surface modifying chemicals. the arrangement of surface monitoring devices 1 being before and after the surface conditioning device 5 allows an operator to monitor performance of the surface conditioning device 5, and make any required changes to this surface conditioning device 5 to ensure that the condition of the rail 2 is optimised.

-13 -Tins railway vehicle 17 may incorporate the operating interface 4 within the driver's cabin. A driver may be presented with the results of the surface monitoring device 1 on a driver display 18. This is to allow the driver to alter how they drive the railway vehicle 17 in response to the results of condition of the rails 2. For an example, the driver may need to increase stopping distances, should the reading from the surface monitoring device 1 suggest the presence of contaminants, or an increased risk of slip. Likewise, the results may allow an increase in speed, safe in the knowledge that the condition of the rails 2 has been optimised. the driver may also be provided with information on the driver display 18 that directs them to switch on any onboard surface conditioning devices 5, having identified a poor condition of rail 2 along which the railway vehicle 17 is passing. 't he railway vehicle 17 in Figure 3 is specifically for cleaning and conditioning railway track rails 2. The surface monitoring devices 1 allow such a railwa.y vehicle 17 to directly respond to a change in surface condition, whilst also providing the operator with real-time feedback as to die cleaning performance of their railway vehicle 17. The operator is then able to adjust their level of cleaning and conditioning of a section of rail 2 accordingly, rather than simply cleaning all rails 2 by the same amount, or by making a decision of cleaning level by sight alone.

Figure 4 shows a further arrangement of surface monitoring device 1 when mounted to the undercarriage of a passenger carrying railway vehicle 17. 't he close-up shown shows the surface monitoring device mounted to the undercarriage, and configured such that the monochromatic light source 8 of the spectrometer 3 acts directly upon the rail 2. The driver's cab may again be provided with the operating interface 4 to control the operation of the surface monitoring device 1, and may also comprise a driver display 18. 't his driver display 18 may relay the data recorded by die surface monitoring device 1 directly to the driver, Or it may process this data to provide top-level information -14 -to the driver, to allow them to instantaneously alter their driving according to real-time rail conditions. For an example, the surface monitoring device 1 may feed through rail condition data that falls outside of predetermined parameters, indicating that a particular section of rail 2 is not in an optimum condition. This may simply be shown to a driver as a red flag, that enables them to make an instant decision to allow more time to decelerate, allowing for greater stopping distances, and to reduce their speed until the data recorded falls back within an optimal range.

In all embodiments, display 4 may indicated detailed data representing the condition of monitored rails 2. Additionally or alternatively, it may simply indicate if the condition of a monitored rail is either GOOD or BAD -indicated in Figure 1 by a tick or a cross. This enables a driver or 1\401\4 to respond quickly to either change speed or request track conditioning, without having to spend time analysing more detailed data.

By mounting surface monitoring devices 1 to a considerable number of railway vehicles 17 running within a rail network, a. ra.il operator can build up a. much bigger picture of rail condition throughout the entire network, on an instantaneous basis, and be better prepared to react to am, sudden changes to environmental conditions, that lead to poor rail conditions. 't his vastly improves the safety of the rail network, allowing for surfa.ce conditioning to be directed towards specific areas of concern.

Figure 5 shows a schematic diagram of one possible arrangement of surface monitoring device 1, comprising a probe 9 for directing light from monochromatic light source 8 onto a surfa.ce. The monochromatic light source 8 is likely to be a laser, and therefore this laser is configured to transmit laser beams 14 onto a. surface through the probe 9. Electromagnetic radiation from -15 -the surface, in the form of scattered photons 15, is collected by a lens within spectrometer 3, and sent through a grating 11. Hie grating 11 filters out any noise, or interference within die light of a wavelength that corresponds with dial of the original laser beam 14, whilst allowing the remaining collected light to be dispersed into a detector 12. 'these components may be contained within a housing, such as the handheld device 6 of Figure 1, or it may be contained within a housing,-that is suitable for mounting,-onto die undercarriage of a railway vehicle 17.

t he surface monitoring device 1 is provided with a power supply 16 that 10 may be a battery, or may use regenerative power, and that provides a source of power to all of die components that make up the surface monitoring device 1.

One type of spectrometer 3 that may be used is a RAMAN spectrometer, which is a form of vibrational spectroscopy. 't he laser beam 14 is beamed onto the surface of the rail 2, which leads to absorption and scattering of photons. Most of these scattered photons 15 have identical wavelengths as the original photons and are therefore termed 'Rayleigh scatter'. However, a very small amount of the scattered photons 15 are moved to an alternate wavelength, termed 'RAMAN scatter'. The majority of these RAMAN scattered photons 15 are moved to greater wavelengths. 't he original photon leads to excitation of electrons, which move into greater energy positions, before they fall back to a lower level and radiate a dispersed photon. If the electron falls back to its original level, it leads to Rayleigh scattering. However, if the electron falls back to a different level, then Raman scattering occurs.

The advantages of RAMAN spectroscopy are that it is very effective for 25 chemical examination of a surface due to its high specificity, aqueous system compatibility, lack of particular sample preparation, and short timescale. Raman -16 -bands have an exceptional signal-to-noise ratio and do not overlap. Raman bands are unaffected by water, and therefore good spectra can be collected from a surface containing considerable water molecules. The probe 9 with a Raman spectrometer 3 does not have to contact the rail 2, but the laser beam 14 lights up the rail 2, and measures the scattered photons 15. A Raman spectrum can also be amassed in a few seconds, allowing for real-time surface conditions to be monitored. A BRAVO device from RAMAN uses fluorescence mitigation SSETm (Sequentially Shifted Excitation) & Duo I.ASF,RTm excitation using two lasers with different wavelengths resulting in high sensitivity across die largest spectral range. 'these features can enable much more accurate measurements, and by focussing on specific wavelengths may lead to faster and more accurate measuring in the Railway optimised product.

By limiting the Raman spectroscopic analysis to frequencies of particular interest, corresponding to anticipated contaminants of interest, scanning can be carried out much more quickly than if broadband frequencies are scanned. This leads to critical data being available to a driver or other operative much more quickly, thereby improving safety on the railway network.

A laser creating the laser beam performs well as the monochromatic light source 8 as it provides a sufficient intensity to generate an effective concentration of Raman sca.tter therefore permitting a clean spectrum, with little to no extraneous bands. The laser displays excellent wavelength stability and minimal background emission.

t he probe 9 collects the scattered photons 15, whilst filtering out the Rayleigh scatter and a.dditional background signals from any fibre optic cables. Tt 25 then transmits this information to the detector 12 via the spectrometer 3 for analysis. The scattered photons initially enter the spectrometer 3 and are -17 -transmitted through the grating 11, w nth acts to separate them by wavelength, before they are carried to the detector 12. This measures the intensity of the Raman signal at each wavelength, which is then plotted as die R2unan spectrum. Typical frequencies have a wavenumber selected from the group comprising 640, 1430, 1480, 1260, 1213, 1240, 1580, 2000 cm-1. These frequencies correspond to biochemical compounds relevant to leaf materials and therefore of particular interest to drivers or other operatives.

The surface monitoring device 1 is configured to compare a monitored value with one or more predetermined values and to provide a corresponding device output that indicates whether the condition of the rail 2 is above or below a predetermined acceptable level. The Raman spectrometer output is indicative of both type and amount of contaminant.

in this specification, the verb "comprise" has its normal dictionary meaning, to denote non-exclusive inclusion. That is, use of the word "comprise" (or any of its derivatives) to include one feature or more, does not exclude the possibility of also including further features. The word "preferable" (or any of its derivatives) indicates one feature or more that is preferred but not essential.

All (Jr any of the features disclosed in this specification (Including any accompanying claims, abstract and drawings), and/or all or any of the steps of any method (Jr process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving 25 the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, -18 -unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

t he invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

-19 -CLAIMS1. A device for monitoring the condition of the surface of railway track rails, the device comprising a spectrometer configured to monitor at least one frequency that indicates the presence of a contaminant on a railway track rail and to provide an output indicative of the presence or absence of the contaminant on a railway track rail.
2. A monitoring device according to claim 1, wherein the spectrometer is configured to monitor a. plurality of frequencies that indicate the presence of contaminants on a railway track rail 1 0
3. A monitoring device according to claim 1 or 2, wherein the spectrometer is a. Raman spectrometer.
4. A monitoring device according to claim 1, 2 or 3, being a hand held device.
5. A monitoring device according to claim 1, 2 or 3, mounted alongside 15 and directed at a railway track rail and operative to provide an output indicative of the presence or absence of contaminants on the rail
6. A monitoring device according to claim 5, mounted alongside and directed at a plurality of railway track rails and operative to provide an output indicative of the presence or absence of contaminants on the rails.
7. A monitoring device according to a.ny of the preceding claims, wherein said contaminants to be monitored comprise at least one from the group consisting of Cellulose, Cellulose Acetate and Tyrosine.-20 -
8. A monitoring device according to any of the preceding claims, wherein said frequencies have a wavenumber selected from the group comprising 640, 1430, 1480, 1260, 1213, 1240, 1580, 2000 cm-I.
9. A monitoring device according to any of the preceding claims, wherein the device is configured to compare a monitored value with one or more predetermined value and to provide a corresponding device output that indicates whether die condition of a monitored railway track rail is above or below a predetermined acceptable level.
10. A monitoring device according to any of the preceding claims, wherein 1 0 the Raman spectrometer output is indicative of both type and amount of contaminant.
11. A monitoring device according to any of the preceding claims, including an operating interface whereby a user can control operation of the monitoring device.
12. A monitoring device substantially a.s herembefore described with reference to die accompanying drawings.
13. A monitoring device according to any of the preceding claims, m combination with a surface conditioning device for railway track rails, the surface conditioning device being operative to condition the surface of one or more 2 0 railway track rail in response to data received from the monitoring device.
14. A combination according to claim 13, wherein said surface conditioning device is operative to condition a railway track rail by means of plasma delivered to the rail.-21 -
15. A railway vehicle provided with at least one monitoring device or combination according to any of the preceding claims.
16. A railway vehicle according to claim 15, having a driver's cab that receives an output from said at least one monitoring device.
17. A railway vehicle according to claim 15 or 16, having at least two said monitoring devices at spaced locations along the vehicle or along a train that is driven by the vehicle.
18. A method of monitoring the condition of the surface of a railway track rail, the method comprising operating a monitoring device according to any of claims 1 to 12 to indicate the presence of contaminants on the rail and to provide an output indicative of the presence or absence of contaminants on the rail.
19. A method according to claim 18, comprising the further step of operating a surface conditioning device to condition the surface of the rail in 15 response to data. received from the monitoring device.
20. A method according to claim 18 or 19, carried out on a railway vehicle according to claim 15, 16 or 17 as it travels along the railway track rail.
21. A method according to claim 20, carried out as the railway vehicle makes multiple passes along the railway track rail.
22. A method of monitoring the condition of the surface of a. railway track rail, the method being substantially as hereinbefore described with reference to the accompanying drawings.-22 -
23. A method of monitoring and conditioning the surface of a railway track rail, the method being substantially as hereinbefore described with reference to die accompanying drawings.