GB2428724A

GB2428724A - A datum monument

Info

Publication number: GB2428724A
Application number: GB0515606A
Authority: GB
Inventors: Stephen Ingleton; Robert Silver
Original assignee: Laser Rail Ltd
Current assignee: Laser Rail Ltd
Priority date: 2005-07-29
Filing date: 2005-07-29
Publication date: 2007-02-07
Also published as: GB0515606D0; WO2007012851A1

Abstract

A datum monument for a railway infrastructure, the monument comprising a mounting to define a dependable position for the monument and an identifier for interrogation with respect to particular information indicative of the dependable position environs.

Description

Datum Monument The present invention relates to datum monuments, and more

particularly to such datum monuments associated with a railway structure in order to give details with regard to part of the adjacent railway infrastructure. These monuments may be passive or active in terms of providing information with regard to railway infrastructure.

Safety is of critical importance with regard to railway infrastructure. In order to achieve the level of the safety necessary with regard to railway infrastructure it is important to ensure that the track is properly maintained. In such circumstances railway infrastructure is regularly inspected and monitored.

Such inspection and monitoring has traditionally been performed by workers walking the track in order to inspect the rails and identify any problems. More recently automated systems have been used to improve the accuracy of inspection and the speed of such inspection.

Automated inspection machines travel along the track and can measure a number of parameters including track alignment, cant, curvature and other factors. These machines are faster and generally more accurate than manual inspection, but it will be understood dependent upon calibration and expected results to achieve by comparison the necessary levels of inspection accuracy and performance.

In accordance with the present invention there is provided a datum monument for a railway infrastructure, the monument comprising a mounting to define a dependable position for the monument and an identifier for interrogation with respect to particular information indicative of the dependable position environs.

Preferably, the particular information provides a calibrated position for the monument. Additionally, the particular information may include cant, curvature, a unique monument reference number, offset diameter, kilometerage, chainage, track (BRS) code, geographical co-ordinates relative to a structural form, such as a rail, and date of installation. Possibly, the particular information is periodically updated.

Possibly, the identifier comprises a visibly readable textual member.

Alternatively or additionally, the identifier comprises an electrically readable storage device. Further possibly, the identifier is machinery readable by an inspection machine. Additionally, the identifier comprises a periphery profile for the monument.

Generally, the mounting comprises a spigot and locking mechanism securing the monument to the spigot. Possibly, the locking mechanism has a security feature to prevent unauthorised removal of the monument from the dependable position. Typically, the locking mechanism comprises a nut or other fastening mechanism. Generally, the nut requires a reciprocally shaped tool to turn the nut for release of the spigot in order to provide the security feature.

Possibly, the identifier is positioned upon an end of the spigot. Typically, the identifier is a prism secured upon the end of the spigot. Generally, the prism allows determination of position.

Possibly, the identifier is formed upon an external part of the monument.

Additionally, or alternatively, the identifier is embedded within a monument block.

Potentially, the monument is specifically shaped for distinct recognition of the monument. Potentially, the distinct recognition relates to a generic type of monument for a particular type of dependable position.

Alternatively, the monument is specifically coloured for distinct recognition.

Advantageously, the monument is specifically coloured for distinct recognition of a particular type of dependable location.

Typically, the identifier is removable from the monument.

Possibly, the identifier is secured to the monument by adhesive, weld or other robust securing mechanism.

Possibly, the monument includes a calibration feature to allow calibration relative to other monuments. Typically, the calibration feature comprises a recess to allow a calibration tool of specific dimensions to span two or more datum monuments.

Also in accordance with the present invention there is provided a railway infrastructure inspection combination comprises a datum monument as described and an inspection machine, the inspection machine arranged to be presented relative to the datum monument for interrogation of the monument to obtain the particular information, the inspection machine including a sensor to inspect a railway infrastructure feature to provide an inspection result to a comparator for comparison with the particular information, the comparator indicating the degree of correspondence between the particular information and the inspection result.

Typically, the sensor comprises a laser arc profiling device.

Generally, the combination includes a plurality of monuments. Generally the plurality of monuments are spaced along sections of a railway infrastructure.

Typically such spacing is regular. Additionally, the plurality monuments may be vertically spaced around a section of the railway infrastructure. Typically the vertically spaced monuments are jn a common plane.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings in which:Fig. 1 is a top front perspective view of a datum monument; Fig 2 is a bottom front perspective view of the datum monument depicted in Fig 1; Fig 3 is a cross section of the datum monument depicted in Figs 1 and 2; Fig 4 is a front bottom perspective view illustrating an end to a spigot with a prism and prism interface; Fig. 5 is a schematic view of a proportion of rail infrastructure incorporating monuments in accordance with the present invention; Fig. 6 is a cross-sectional view of a tunnel incorporating monuments in accordance with the present invention and an inspection or surveying machine in outline; and Fig. 7 is a cross- sectional view of the tunnel depicted in figure 6 using a calibration tool.

As indicated above it is very important with regard to railway infrastructure to ensure that there is adequate maintenance and inspection of the infrastructure. Although manual inspection is useful, more recently it has been found inspection machinery can perform the task more efficiently and with increased speeds so that inspections can be performed on a more regular basis. UK patent application No. 0405914.3 (Laser Rail) describes one such approach to providing an inspection machine for railway infrastructure and in particular tunnels and cuttings. These inspection machines can accurately monitor rail positions in terms of orientation alignment and relative positioning to features such as the walls of a tunnel.

However, it will be understood that different parts of the railway network will be designed and installed with differing features and structures. In such circumstances it would be desirable for the inspection machine to be able to appreciate and compare the expected railway infrastructure to be inspected with that actually being seen by the inspection machine. The present invention provides datum monuments for distribution about the railway infrastructure in order to enable inspection machinery and for that matter, manual inspectors to be informed about the particular part of the railway infrastructure adjacent to the monument environs.

Each monument is designed to provide a means of establishing a reliable datum position on railway infrastructure for which the precise location of track position can be initially established and subsequently monitored. The monument(s) are placed throughout railway infrastructure at regular intervals and identify the longitudinal position (chainage) along infrastructure alignments. The monuments are also able to store information in relation to its location within the infrastructure i.e. cant, curvature and offset from the running rail. The stored information can be displayed on the monument and/or embedded within a programmable chip for subsequent visibility, access and replacement. The intelligent monument is also designed to facilitate operation with laser measuring equipment of inspection machines through a shaped recognition system and can facilitate the fitment of a survey prism for establishing is position within the alignment by conventional survey methods.

In order to provide a reliable datum position on a railway infrastructure it will be understood that firstly a dependable position for the monument must be established. Each monument generally consists of a means of securely mounting that monument to a structural feature associated with the railway infrastructure. This structural feature may be a wall of a tunnel or a part of any fixed structure, such as track, or a stable post adjacent to the railway infrastructure. Figures 1 to 3 illustrate an example datum monument 1 in which a locating spigot 2 is securely fixed at one end to a structural feature (not shown) such as a tunnel wall surface as described above in order to dependably locate a monument housing or block 3 relative to a railway infrastructure. The monument block 3 is secured upon the spigot 2 by a locking nut 4 or any other fastener. As will be described later an exposed end of the spigot 2 may be used to provide an identification point for the datum block 1. The exposed end 5 may be protected by a cap when not in use.

Each datum block 1 generally includes identifier features including a textual identification panel 6 and a machine readable panel 7, along with potentially identification provided by an exposed end 5 of the spigot 2 which can be interrogated for position.

It is important that the datum monument 12 provides a dependable position so it is typically necessary that the locking nut 4 or any other fastener is secured by a reciprocally shaped tool to ensure that there is a degree of security with respect to authorisation to remove the block 3 from the spigot 2.

As indicated above it will be appreciated that the assembly of the datum monument is performed by firstly fastening the locating spigot 2 to the infrastructure. The block 3 is then placed over the secured spigot 2 and secured in place by the locking nut 4 or other fastening mechanism.

Generally each datum monument 1 will have a unique identifier in terms of its reference number and other features. These unique identifiers will generally be provided in the textual identifier 6 and replicated in the machine readable identifier 7. The machine readable identifier 7 will also generally incorporate data in a machine readable form with regard to location, longitudinal position (chainage), cant, curvature and offset from a running rail. This information may be updated upon each inspection by the inspection machine for identification of trends in terms of variations in track alignment, curvature and offset. It will be appreciated that in some circumstances with a number of such datum monuments regularly or specifically placed about the railway infrastructure it will be able to collate all of the particular information provided by the identifiers 5, 6, 7 in the processor of the inspection machinery in order to produce a report with regard to long term trends and specific deviations in the comparisons performed at each individual inspection by the inspection machine.

With regard to the spigot 2 it would be understood that generally this will be formed from a stable and robust material such as steel. Furthermore the spigot is designed to accommodate fixing to a large number of infrastructure types with an installation end 8 produced in the form of peg or screw thread form for subsequent bonding or mechanical attachment to the structural feature of the railway infrastructure.

The exposed end 5 provides particular information such as a location reference point for the datum monument 1. The end 5 will include a marker from which the monument 1 position in relation to the infrastructure can be measured. Typically the end 5 will be colour coded for particular information sourcing when interrogated either manually or through machine reading features of an inspection machine. Most advantageously the end 5 will take the form of an identifier prism which will provide a positional response to interrogation in order to enable the datum monument I and its position within a railway infrastructure to be determined. In particular use of a prism at the end 5 will enable infrastructure alignment to be recorded during typical inspection and surveying of railway infrastructure. It would be understood that a prism can be secured to the end 5 with the block 3 secured to the spigot 2 so that in such circumstances the block 3 and its identifiers 6, 7 can be changed whilst the identification information provided by the end 5 remains consistent. This may be useful during upgrading or a period of track maintenance.

With regard to the monument block 3 this can be produced from a range of materials including aluminium, steel or a composite material including an extruded form. It will be understood that the actual block 3 shape may be formed in such a manner that it is distinctive for a particular type of datum monument 1 itself. In such circumstances datum monuments associated with bends or curvature in the railway infrastructure may well be of respectively different shapes and colours readily appreciated by manual inspection or by an inspection machine. The colours will be designed to meet professional requirements for the working environment and laser measuring devices of inspection machines. As indicated the peripheral shape or variations of the block 3 may be specially constructed to provide themselves a recognisable identifier using laser measuring apparatus in an inspection machine. In such circumstances the exterior periphery of the block 3 may indicate to the measuring machine the location of the other identifiers 5, 6, 7 in the monument for appropriate interrogation coupling. When specifically contoured it will be understood that the monument designs will be such that they will be captured by a laser measuring device when that laser is static or dynamically passed over or across the contoured surface of the block at various speeds.

Typically, the block will generally be approximately 100mm high by 30mm in depth by 60mm in length in order to be identifiable within the tolerance ranges of a laser system so that the block can be recognised. However, it will also be understood that the specific dimensions of the block can be adjusted for particular infrastructure requirements and types of laser measuring apparatus used for interrogation.

The nut 4 is produced from a steel or other robust material to ensure that the block 3 is held securely in place at a dependable position and location.

Typically the nut is designed to be fixed or removed using a socket head.

This may be a standard socket head but in order to provide security, a special reciprocally shaped tool may be required to remove the nut 4 and so allows removal of the block 3 only by authorised personnel. It will be understood that other forms of fixing may also be used.

As indicated above normally the datum monument 1 will incorporate a number of identifiers, but it will also be understood that the block may simply comprise one suitable identifier which may be interrogated appropriately. Typically the block 3 will be associated with a textual identifier 6 which is a plaque formed from aluminium, steel or a composite material and designed to textually record specific details about the location of the datum monument I in relation to the infrastructure. This will also provide general location and reference within the railway infrastructure for maintenance and repair staff when instructed to perform operations. Thus, a textual reference may be used by these personnel to identify which part of the track requires remedial or repair actions when appropriately instructed, and similarly when manual performing inspections provides a location for reporting inspections. Typically the details recorded on the textual identifier 6 will include a unique identification number, longitudinal location (chainage) from a reference longitudinal position, cant, offset, curvature, geographical co-ordinates in relation to the track and a date of installation. Thus the textual identifier 6 provides an inventory record for management purposes as well as a general locator for personnel as described above, It will be understood that the identifier panel 6 can be fitted at the same time as the monument 1 is installed at its dependable location or during manufacture of the block 3. Although illustrated as a single panel 6 it will be understood that textual identifiers may comprise one or a series of plaques secured to the block 3. In such circumstances, a permanent identifier plaque may be secured with the block 3 which cannot be removed whilst inspection history identifier plaques are secured as required by removal and replacement of the previous information.

The machine readable identifier 7 will normally be produced from a composite material and either be secured externally on the periphery of the block 3 or more normally embedded within the block 3. In such circumstances the identifier 7 will be an integrated circuit or programmable chip designed to accept and provide specific details about the location of the datum monument 1 in relation to the infrastructure when interrogated by an inspection machine or hand held machine interrogation device. As with the textual identifier 6, typically the specific and particular information stored by the identifier 7 will relate to a unique identification number for the datum monument 1, longitudinal position (chainage), cant, curvature and offset with regard to an associated part of the railway infrastructure and date of installation, but it will also be understood that the storage capacity of an electronic device such as that envisaged with respect to the machine readable identifier 7, will allow a far greater range of particular information to be provided and stored by the identifier 7. As indicated previously this may allow inspection to inspection trend comparisons if the identifier 7 acts as a local store for information in relation to the infrastructure. The programmable identification provided by the identifier 7 will again either be fitted on site or located within the monument block 3 during assembly and manufacture. Machine reading may be through a wireless link possibly initiated by a laser incidence trigger, hand held device or other system.

It would be understood that the monuments I in accordance with the present approach will be designed to provide calibration checks in combination with inspection machines. It will be understood that most inspections are relative and therefore it is important that the inspection machine itself is calibrated. In such circumstances each monument or more normally by a comparative interrogation of a number of monuments, it will be possible to calibrate the inspection machine. It will be understood it is possible that one monument might show true deviations but it will be unlikely that a great number of monuments will become deviated, therefore statistically it is possible to calibrate the inspection machinery relative to that number of monuments.

More particularly, as described later with regard to figures 6 and 7 it is possible to provide a calibration tool frame so that two or more monuments secured generally in a common plane or relationship within a tunnel can be reliably associated with each other in order to provide surety with respect to their relative calibration and therefore provide calibration of an inspection machine either as an individual calibration set or through comparison with other calibration sets of monuments.

As indicated above datum monuments 1 in accordance with the present invention will generally include a number of identifiers. The block may be removable from a dependably located spigot so that the individual identifiers in a monument can be separated. A prism secured on the end of the spigot will still provide accurate X and Y axis positioning for the spigot and so the monument. This spigot may include at its end 5 its own specific identifier for location inspection by a machine readable device so that irrespective of the block secured to that spigot, that information is consistent and notifiable. The block will then include identifier 5, 6, 7 which may be variable dependent upon circumstances. Thus, the monument 1 position known consistently through its identifier provided at the end 5 whilst the block in terms of the textual identifier 6 and machine readable identifier 7 may be altered to account for particular railway infrastructure features. In such circumstances as indicated, the base identifier provided by the end 5 will be maintained whilst the block 3 and its identifiers 6, 7 changed. Such a situation may occur when for example a part of the railway infrastructure is altered in terms of the requirements with respect to proximity of the infrastructure or as indicated as a result of providing a local record with respect to variations in offset, curvature and cant.

The monument block I will also be able to transfer a representation of the local cross-section of the infrastructure for comparison. It may also be possible by replacing a block 5 to provide a trigger for more intense monitoring and inspection by an inspection machine over the next section of track. This trigger as indicated may be achieved by different peripheral profiling for the block which will be recognised by a laser measuring or scanning device utilised in an inspection machine.

Figure 4 provides a schematic illustration of the use of a prism interface 9 to interrogate the end 5 of the spigot securing the monument 1. This prism interface 9 will typically utilise a laser to interrogate the end 5 in order to measure its position. This position and a reference will then through an appropriate look up table provide a known determination of the monument I position. This accurate determination of monument 1 position will be provided and determined upon installation of the monument 1 and in particular, the spigot 2 (not shown) which includes the end 5. In such circumstances irrespective of the textual block 5 secured to the spigot with the end 5 it will be understood that, that location will be known for the monument 1. In such circumstances through the end 5 being in the form of a prism and the interface 9 it will be understood an inspection machine will then appreciate its position in the railway infrastructure. The inspection machine can then interrogate the identifiers 6, 7 to upload that data necessary for comparison during the inspection over the next part of the railway infrastructure or through knowledge of the location to upload information from a data source with respect to the expected inspection criteria over that next section of railway infrastructure or a combination of the two for comparison. It will be understood that the monument 1 will provide a local indicator as to the last date of inspection and the inspection machine or manual inspector will be reminded as to potential sources of concern previously raised in order to more closely input those structural features for persistence in the deviation from that expected.

Figure 5 provides a schematic illustration of a portion of railway infrastructure 20. It will be apparent that this is a simple branch line railway infrastructure and more complicated railway infrastructures will be generally in existence.

Nevertheless, it can be seen that a main railway track 21 passes through a tunnel 22 whilst a branch line 23 includes a cutting with embankments 24 either side. In such circumstances within the railway structure 20 datum monuments 25 are provided at regular spacing to provide local information with regard to railway infrastructure. It will be noted that the monuments 25 are of particular use in situations where there are structural features such as tunnels or cuttings in order that the relationship between the track 21, 23 and the structures 22, 24 can be determined. It will be understood that railway infrastructure in terms of a track 21, 23 is secured upon the ground and in relation to the structural features 22, 24. In such circumstances through natural tectonic movements, subsidence and compressions as railway engines pass along the tracks 21, 22 can cause wear and tear, distortion and displacements of the tracks 21, 23. It is with regard to these variations that the present invention provides the monuments 25. Regular spacing of the monuments 25 allows local comparison with the inspected infrastructure 20 as well as monument 25 to monument 25 comparison by the inspection machine or manual inspection. The monuments 25 provide through the textual identifier as well as machine readable identifiers - the ability to locally determine variations and deviations of the inspected infrastructure.

It will be appreciated from the above that it is important that location of the monument is dependable. In such circumstance a positioning system can be utilised in order to accurately determine monument position and record than on the identifier. It will also be understood that monument position can be determined by typical surveying techniques including triangulation from known reference points and nodes. However, the present datum monuments are also particularly useful with regard to closed structures such as tunnels and in such circumstances means for dtermining monument position must be provided. In such circumstances in accordance with the present invention internal calibration will be provided. In such circumstances and as depicted in figures 6 and 7, monuments will generally be located on a common plane or cross-section. With such multiple monument configurations, each monument can provide calibration with respect to the other monuments in the group.

In figure 6 as can be seen four datum monuments 30 are provided. These monuments 30 will be inspected using an inspection machine shown by broken line 31. Thus by a combination of the inspection machine 31 and the monuments 30 it will be possible to inspect a tunnel 32 by moving the machine 31 along the tunnel 32 such that generally through a laser measurement apparatus within the machine 31 variations in the shape of the tunnel 32 as well as the position of rails 33 can be determined. It is by movement of the monuments 30 that these variations can be identified by the machine 31. It will be understood that upon installation it is important that the monuments 30 are at least initially accurately positioned relative to each other to act as a reference for subsequent inspections. It is only by accurate installation positioning that subsequent variations can be determined.

Figure 7 illustrates use of a calibration tool 34 which is used to ensure that at least two monuments 30a, 30b and 30c and 30d are accurately positioned relative to each other. Thus although the absolute positioning of monuments within the tunnel 32 may only be notionally known it will be understood through use of the calibration tool 34 and appropriate setting of position by the calibration tool 34 any subsequent deviations can be determined through comparison of the monuments 30a relative to 30b and monument 30c relative to monument 30d from that set by the calibration tool 34. It will be understood the calibration tool 34 spans between two monuments 30 but tools could be provided which encompass greater numbers of monuments 30. In such 1 5 circumstances initially upon installation a number of relatively well known node points in the form of monuments 30 will be accurately set so that any subsequent inspection through an inspection machine 31 (figure 6) can utilise distortions and variations in these node (monument 30) positions to determine by appropriate analysis changes in the tunnel 32 shape and rail 33 positions in terms of shift and tilt etc. It will be understood that the monuments 30 when inspected by a laser measuring device will provide as indicated recognisable features in the laser profile response. These features as indicated may include prism responses from the ends 5 of spigots 2 (figures 1 - 3) as well as shapingof the monuments 30 themselves. In such circumstances the laser profile will note variations in the tunnel 32 profile as well as positioning of the monuments 30 within that profile to allow analysis of the tunnel 32, rails 33 and a foundation surface 35 upon which the rails 33 are secured.

It will be understood that the present monuments are used in combination as indicated, preferably with an inspection machine with laser profiling. Thus, the inspection machine 31 will effectively interrogate the monuments 1, 30 in order to provide a profile which as indicated may define a tunnel 32 or simply provide information as to position. In short the monument provides an identifier for interrogation by an inspection machine or hand held reader device or other system in order to obtain particular information with regard to the railway infrastructure about a dependable position at which the monument is secured. The monument can either be incorporated into the profile acquired by a laser profiler, or simply through its shape and identifiers 5, 6, 7 provide an indication as to position and other particular information so that other inspection mechanisms than a laser profiler device can be used in order to assess railway infrastructure condition.

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims 1. A datum monument for a railway infrastructure, the monument

comprising a mounting to define a dependable position for the monument and an identifier for interrogation with respect to particular information indicative of the dependable position environs.
2. A monument as claimed in claim 1 wherein the particular information provides a calibrated position for the monument.
3. A monument as claimed in claim 1 or claim 2 wherein the particular information may include cant, curvature, a unique monument reference number, offset diameter, kilometerage, chainage, track (BRS) code, geographical co-ordinates relative to a structural form, such as a rail, and date of installation.
4. A monument as claimed in any of claims 1, 2 or 3 wherein the particular information is periodically updated.
5. A monument as claimed in any preceding claim wherein the identifier comprises a visibly readable textual member.
6. A monument as claimed in any preceding claim wherein the identifier comprises an electrically readable storage device.
7. A monument as claimed in any preceding claim wherein the identifier is machinery readable by an inspection machine.
8. A monument as claimed in any preceding claim wherein the identifier comprises a periphery profile for the monument.
9. A monument as claimed in any preceding claim wherein the mounting comprises a spigot and locking mechanism securing the monument to the spigot.
10. A monument as claimed in claim 9 wherein the locking mechanism has a security feature to prevent unauthorised removal of the monument from the dependable position.
11. A monument as claimed in claim 9 or claim 10 wherein the locking mechanism comprises a nut or other fastening mechanism.
12. A monument as claimed in claim 11 wherein the nut requires a reciprocally shaped tool to turn the nut for release of the spigot in order to provide the security feature.
13. A monument as claimed in any preceding claim wherein the identifier is positioned upon an end of the spigot.
14. A monument as claimed in claim 13 wherein the identifier is a prism secured upon the end of the spigot.
15. A monument as claimed in claim 14 wherein the prism allows determination of position.
16. A monument as claimed in any preceding claim wherein the identifier is formed upon an external part of the monument.
17. A monument as claimed in any preceding claim wherein the identifier is embedded within a monument block.
18. A monument as claimed in any preceding claim wherein the monument is specifically shaped for distinct recognition of the monument.
19. A monument as claimed in any preceding claim wherein the distinct recognition relates to a generic type of monument for a particular type of dependable position.
20. A monument as claimed in any preceding claim wherein the monument is specifically coloured for distinct recognition.
21. A monument as claimed in any preceding claim wherein the monument is specifically coloured for distinct recognition of a particular type of dependable location.
22. A monument as claimed in any preceding claim wherein the identifier is removable from the monument.
23. A monument as claimed in any preceding claim wherein the identifier is secured to the monument by adhesive, weld or other robust securing mechanism.
24. A monument as claimed in any preceding claim wherein the monument includes a calibration feature to allow calibration relative to other monuments.
25. A monument as claimed in any preceding claim wherein the calibration feature comprises a recess to allow a calibration tool of specific dimensions to span two or more datum monuments.
26. A datum monument for a railway structure substantially hereinbefore described with reference to the accompanying drawings.
27. A railway infrastructure inspection combination comprises a datum monument as claimed in any preceding claim and an inspection machine, the inspection machine arranged to be presented relative to the datum monument for interrogation of the monument to obtain the particular information, the inspection machine including a sensor to inspect a railway infrastructure feature to provide an inspection result to a comparator for comparison with the particular information, the comparator indicating the degree of correspondence between the particular information and the inspection result.
28. A combination as claimed in claim 27 wherein the sensor comprises a laser arc profiling device.
29. A combination as claimed in claim 27 or claim 28 wherein the combination includes a plurality of monuments.
30. A combination as claimed in any of claims 27 to 29 wherein the plurality of monuments are spaced along sections of a railway infrastructure.
31. A combination as claimed in claim 30 wherein such spacing is regular.
32. A combination as claimed in claim 30 or claim 31 wherein the plurality monuments may be vertically spaced around a section of the railway infrastructure.
33. A combination as claimed in any of claims 30 to 32 wherein the vertically spaced monuments are in a common plane.
34. A railway infrastructure inspection combination substantially hereinbefore described with reference to the accompanying drawings.
35. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.