EP4126632A1

EP4126632A1 - Surface condition monitoring of railway tracks

Info

Publication number: EP4126632A1
Application number: EP21723338.6A
Authority: EP
Inventors: Julian Swan
Original assignee: Plasmatrack Ltd
Current assignee: Plasmatrack Ltd
Priority date: 2020-04-02
Filing date: 2021-04-06
Publication date: 2023-02-08
Also published as: GB2593767A; JP2023522157A; GB2593825B; AU2021246970A1; GB202104894D0; US20230192160A1; CA3174257A1; GB202004903D0; WO2021198713A1; GB2593825A; CN115916621A

Abstract

A network of monitoring devices 1 for monitoring the condition of the surface of railway track rails 2, each of the monitoring devices 1 comprising a spectrometer 3 configured to monitor at least one frequency that indicates the presence of a contaminant on a railway track rail 2 and to provide an output indicative of the presence or absence of the contaminant on a railway track rail 2, and each of the monitoring devices 1 comprising a transmitter 19 arranged to transmit its output to a central database 20. The central database 20 is configured to store data from the monitoring devices 1 over time, thereby to establish historical data of track conditions as monitored by the monitoring devices 1. A comparator 22 is configured to compare current track conditions over the network with historical track conditions over the network, thereby to provide an indication of likely developments of track conditions.

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 ha2ards throughout the year. The rail to wheel interface, typically steel against steel, provides an energy efficient combination, yet this interface can 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 can 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 relies upon the 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 reliable rail to wheel interface that has sufficient friction for the desired rate of 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 away by the passage of trains. Such variance and unpredictability to surface conditions of the rail 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. 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. It was estimated that leaves on the line cost around £60( (million in direct costs each year in the UK alone, which is estimated to amount to around £350million societal costs.

A loss of friction at the 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. The 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 that stopping distances are considerably longer and this 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 or 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. The 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 forming 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 some 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 rails, resulting in signal failure. This can cause an event such as Wrong Side Track Circuit Failure, or WSTCF, 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 slippery 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 the 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 as a paste or otherwise, or the application of adhesion modifying chemicals, onto the rail.

The sand assists adhesion during braking and acceleration. Flowever, using sand may increase the risk of unwanted insulation, and therefore may also contain metal particles. For an example, an adhesion modifier such as Sandite™, a combination of sand, aluminium particles and adhesive. Blasting or coating the rails with sand and substances such as Sandite™ 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 60™ (TG60™) an adhesion enhancer for rails, or 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 Head Treatment Trains or RHTTs, or Multi- Purpose Vehicles or MPVs. Again, a challenge for the rail network operators to factor into the overall operation of the network, ensuring the passage of such rail 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 passes therethrough.

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 on recent or imminent environmental conditions. Alternatively, a track is conditioned at predetermined intervals regardless of any specific indicator that a portion of track has reached a poor level.

The 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 the 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. It is also somewhat limited to the range of contaminants or materials that it is able to detect.

Whilst the prior art attempts to address the issue of detecting the presence of various contaminants on a rail track, it provides no way of evaluating current conditions and predicting future conditions over a rail network. Preferred embodiments of the present invention aim to provide a network of surface monitoring devices that may be improved in this respect.

According to one aspect of the present invention, there is provided a network of monitoring devices for monitoring the condition of the surface of railway track rails, each of the monitoring devices 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, and each of the monitoring devices comprising a transmitter arranged to transmit its output to a central database.

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

Preferably, each spectrometer is a Raman spectrometer.

Preferably, the monitoring devices comprise one or more of the following: handheld device, railway vehicle borne device, track side device, drone mounted device, UAV mounted device, satellite mounted device.

Preferably, said contaminants to be monitored comprise at least one from the group consisting of Cellulose, Cellulose Acetate and Tyrosine.

Each monitoring device may be configured to compare a monitored value with one or more predetermined value and to provide a corresponding device output that indicates whether the condition of a monitored railway track rail is above or below a predetermined acceptable level. Preferably, each spectrometer output is indicative of both type and amount of contaminant.

Preferably, each monitoring device includes an operating interface whereby a user can control operation of the monitoring device. A network according to any of the preceding aspects of the invention may further comprise at least one surface conditioning device that is operative to condition the surface of one or more railway track rail in response to data received.

Said surface conditioning device may be operative to condition a railway track rail by means of plasma delivered to the rail.

Preferably, at least some of said transmitters are wireless transmitters.

Preferably, the central database is configured to store data from the monitoring devices over time, thereby to establish historical data of track conditions as monitored by the monitoring devices. Preferably, a network according to any of the preceding aspects of the invention further comprises a comparator that is configured to compare current track conditions over the network with historical track conditions over the network, thereby to provide an indication of likely developments of track conditions. The method extends to a method of monitoring the condition of the surface of railway track rails of a rail network, the method comprising operating monitoring devices of a network according to any of the preceding aspects of the invention to indicate the presence or absence of contaminants on the rails at various locations throughout the network.

Such a method may comprise the further step of operating at least one surface conditioning device to condition the surface of a rail in response to data received from the monitoring devices.

The surface conditioning 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.

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:

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 railway vehicle, showing a surface monitoring device mounted at the front of the vehicle, and a further surface monitoring device mounted at the rear 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;

Figure 5 shows one embodiment of surface monitoring device as a schematic diagram, showing the component parts that allow the surface monitoring device to detect the presence of a material on a surface, and analyse the composition of the material on that surface;

Figure 6 shows one embodiment of a network of surface monitoring devices along a single track, mounted on railway vehicles, track side and as a handheld device, relaying surface condition data to a central database for evaluation; and

Figure 7 shows one embodiment of a central database obtaining surface condition data from a wider rail network.

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 surfaces. 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. The 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, the handheld device 6 may wirelessly 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 transmitting recorded data back to a central resource through a 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 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 in 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 the 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.

The surface conditioning device 5 in 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.

This 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. The railway vehicle 17 in Figure 3 is specifically for cleaning and conditioning railway track rails 2. The surface monitoring devices 1 allow such a railway vehicle 17 to directiy respond to a change in surface condition, whilst also providing the operator with real-time feedback as to the 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. The 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 directiy 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. This driver display 18 may relay the data recorded by the surface monitoring device 1 directiy to the driver, or it may process this data to provide top-level information 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 MOM 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 rail 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 any sudden changes to environmental conditions, that lead to poor rail conditions. This vastiy improves the safety of the rail network, allowing for surface 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 surface. 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 the surface, in the form of scattered photons 15, is collected by a lens within spectrometer 3, and sent through a grating 11. The grating 11 filters out any noise, or interference within the light of a wavelength that corresponds with that 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 the undercarriage of a railway vehicle 17.

The surface monitoring device 1 is provided with a power supply 16 that may be a battery, or may use regenerative power, and that provides a source of power to all of the 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. The 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. The 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 chemical examination of a surface due to its high specificity, aqueous system compatibility, lack of particular sample preparation, and short timescale. Raman 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.

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 scatter therefore permitting a clean spectrum, with little to no extraneous bands. The laser displays excellent wavelength stability and minimal background emission.

The probe 9 collects the scattered photons 15, whilst filtering out the Rayleigh scatter and additional background signals from any fibre optic cables. It then transmits this information to the detector 12 via the spectrometer 3 for analysis. The scattered photons initially enter the spectrometer 3 and are transmitted through the grating 11, which 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 the Raman spectrum. 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.

Figure 6 shows one example of a plurality of different surface monitoring devices 1 being used throughout a rail network. These surface monitoring devices 1 may obtain data from the rails 2 of a single track, or they may obtain data from rails 2 that make up a much larger network of tracks within a region or country. The surface monitoring devices 1 may be mounted to various rail vehicles that pass along the tracks, they may comprise handheld devices 6 for use by an operative, or they may be mounted track side within a pillar or similar, or any combination of these that suit a particular run of rails 2. Each of these surface monitoring devices 1 is configured to obtain surface condition data, realtime or as and when required, along a length of track within a network, and to wirelessly transmit this data to a wireless receiver 21 of a central database 20.

A network of surface monitoring devices 1 may form an IoT (Internet of Things) enabled network of sensors, software and other technologies for connecting and exchanging data with other devices and/ or systems within the network over the Internet. The uploading of data from these various sources of rail condition can be achieved. Each of these data sources of surface condition is evaluated against a central database for the full network. The data is used to predict current conditions elsewhere in the network and also forecasts conditions for the future. With multiple sources running over the same line a real-time development of the adhesion conditions is also possible, not just a snap shot in time. A spectrometer 3 shown in such an arrangement is transmitting recorded data back to a central resource through a transmitter 19. The 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 in areas where surface condition of the rails 2 is of a particular concern. Rail network operatives may be provided with handheld devices 6 for surface monitoring. They may spot a region rail 2 that is of particular concern, or may wish to perform spot checks to monitor a particular track section. They may undertake cleaning or maintenance of a section of rail 2 and wish to take readings before, during or after this process. The handheld devices 6 may wirelessly transmit this data through a transmitter 19 to a central database 20 for analysis. Various surface cleaning and conditioning devices may be sent out in response to this data to condition the section of rail 2 where the reading was taken.

The central database 20 may therefore receive data, real-time or through download, from multiple sources covering a network. These sources include handheld devices 6 used by track engineering MOMs (Mobile Operations Managers) for instantaneous track evaluation; cleaning vehicle mounted for measuring before and after cleaning; passenger or freight vehicle mounted; track side mounted, positioned near hotspots to aid in prediction of conditions; drone, Unmanned Aerial Vehicle UAV or satellite mounted. This allows the central database 20 to build up the full picture of surface condition of rails that make up a rail network.

One example of central database 20, as shown in Figure 6, is obtaining surface condition data along a single rail line. In this example rail operatives MOMs may go out and measure good rail conditions in the morning, using a handheld device 6. However as the rail traffic continues to pick up and deposit leaf material, the rail conditions will likely deteriorate. Vehicle mounted surface conditioning devices that pass along the rails 2 can read the surface condition and feedback any increase in leaf matter, and track side surface monitors can measure material being added and removed by passing trains. In this case the trains may be redepositing material away from the original site. The network of surface monitoring devices relay all readings to the central database 20, wirelessly. A comparator 22 associated with the central database 20 makes use of historical data and other known data on track conditions, to enable a decision on overall surface condition. If an intervention is needed, a Railhead Treatment Train can be deployed in between scheduled trains. Surface condition readings can be taken before and after cleaning in a preventative maintenance action at a higher speed. This causes minimal interruption to the schedule of passing freight and passenger trains when compared to reactive cleaning of very poor conditions if further deterioration is allowed. This system will improve the operational performance of the line in question.

Figure 7 shows the central database 20 with comparator 22, receiving data through a receiver 21 across an entire rail network. The data gathered over the year, for an example, can be referenced back to a model for good, transitional and poor conditions. By using the surface monitoring devices 1 distributed over the network a picture of the current conditions can be predicted throughout the whole network. An understanding of the changing conditions throughout the network can be modelled and developed. This can therefore enable interventions for cleaning to be forecast more accurately and scheduled with minimum disruption to the whole network.

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 or 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 or 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 the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The 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

1. A network of monitoring devices for monitoring the condition of the surface of railway track rails, each of the monitoring devices 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, and each of the monitoring devices comprising a transmitter arranged to transmit its output to a central database.

2. A network according to claim 1, wherein each spectrometer is configured to monitor a plurality of frequencies that indicate the presence of contaminants on a railway track rail.

3. A network according to claim 1 or 2, wherein each spectrometer is a Raman spectrometer.

4. A network according to claim 1, 2 or 3, wherein the monitoring devices comprise one or more of the following: handheld device, railway vehicle borne device, track side device, drone mounted device, UAV mounted device, satellite mounted device.

5. A network according to any of the preceding claims, wherein said contaminants to be monitored comprise at least one from the group consisting of Cellulose, Cellulose Acetate and Tyrosine.

6. A network according to any of the preceding claims, wherein each monitoring device is configured to compare a monitored value with one or more predetermined value and to provide a corresponding device output that indicates whether the condition of a monitored railway track rail is above or below a predetermined acceptable level.

7. A network according to any of the preceding claims, wherein each spectrometer output is indicative of both type and amount of contaminant.

8. A network according to any of the preceding claims, wherein each monitoring device includes an operating interface whereby a user can control operation of the monitoring device.

9. A network according to any of the preceding claims, further comprising at least one surface conditioning device that is operative to condition the surface of one or more railway track rail in response to data received.

10. A network according to claim 9, wherein said surface conditioning device is operative to condition a railway track rail by means of plasma delivered to the rail.

11. A network according to any of the preceding claims, wherein at least some of said transmitters are wireless transmitters.

12. A network according to any of the preceding claims, wherein the central database is configured to store data from the monitoring devices over time, thereby to establish historical data of track conditions as monitored by the monitoring devices.

13. A network according to any of the preceding claims, further comprising a comparator that is configured to compare current track conditions over the network with historical track conditions over the network, thereby to provide an indication of likely developments of track conditions.

14. A method of monitoring the condition of the surface of railway track rails of a rail network, the method comprising operating monitoring devices of a network according to any of the preceding claims to indicate the presence or absence of contaminants on the rails at various locations throughout the network.

15. A method according to claim 14, comprising the further step of operating at least one surface conditioning device to condition the surface of a rail in response to data received from the monitoring devices.

16. A method according to claim 15, wherein the surface conditioning is carried out on a railway vehicle as it travels along the railway track rail.

17. A method according to claim 16, carried out as the railway vehicle makes multiple passes along the railway track rail.

18. A network of monitoring devices, substantially as hereinbefore described with reference to the accompanying drawings.

19. A method of operating a network of monitoring devices, the method being substantially as hereinbefore described with reference to the accompanying drawings.