Rail panel handler

Abstract

A rail panel handler 10 has a mobile base 12, which may have a rotatable mount 40, and a crane unit 14, such as a telescopic jib crane, mounted onto the mobile base 12. The crane unit 14 has a support

Description

The present invention relates to a rail panel handler designed for handling rail panels, as well as being configurable for handling other heavy loads in rail construction industries. The invention further relates to a rail panel handling system having a plurality of said rail panel handlers, and to a method of handling a rail panel using a rail panel handler. The increased need for efficiency in land use, urbanisation, and the use of rail networks as convenient conduits for other services such as telecommunications systems means that maintenance of railway networks must be carried out in ever more restricted working space. This is exacerbated by the need to keep multi-track railways open at least in part when work is being performed on a single stretch, and becomes even more complex for underground railway networks. Railways are now commonly installed as rail panels. These are prefabricated portions of a railway line which can be installed as one. There is no need to install sleepers separately to the rails. The panels can then be welded to the main rail track. Additionally, when removing sections of worn rails, then these will be extracted as cut panels. To lift a rail panel, there are several machines available. Rail-borne jib cranes are commonly used, having a cantilevered jib crane. Such machines require a substantial counterweight to counterbalance the overturning motion of the crane. Jib cranes are difficult to operate where adjacent rail lines are open to rail traffic, as the counterweight will usually infringe on the adjacent track gauge as the machine slews. Gantry cranes can be provided which have a gantry frame spanning a track. Gantry cranes tend to be considerably smaller and lighter than jib cranes of similar load capacity and are inherently more stable. Rail-borne gantry cranes, however, require an existing rail to run on, and have fallen out of use in favour of caterpillar-tracked gantry cranes. The difficulty with gantry crane systems is that steering becomes difficult, since the load of the rail panel is between the caterpillar tracks. Widening the gantry alleviates this issue, but causes difficulty working in confined regions. Gantry cranes are also usespecific, whereas jib cranes can be easily reconfigured for other lifting operations. The third arrangement known in the art is the motorised carrier and handling system. A static handler with jack legs is used to engage with and grab a rail panel, and a flatbed lifting platform can be driven underneath the rail panel for movement once the jack support is removed. This results in a narrow system with little infringement on adjacent rails, with a greater steering capacity. However, this is again a very bespoke piece of equipment, and therefore becomes redundant in most use cases. The present invention seeks to provide a lifting system for rail panels which has a much greater utility in other rail equipment handling scenarios. According to a first aspect of the invention, there is provided a rail panel handler comprising: a mobile base; and a crane unit mounted onto the mobile base, the crane unit comprising: a support portion, a crane arm extending from the support portion, a load carrying device supported by the crane arm suitable for engaging with a rail panel to be handled, and a jack leg connected to the crane arm, the jack leg being adjustable between an in-use ground-contacting condition for lifting a said rail panel, and an in-use non-ground-contacting condition. The provision of a crane arm which extends from a support portion is the basic concept of a jib crane. However, in order to reduce the size and weight of the rail panel handler, and therefore reduce the prospect of infringement onto adjacent railway lines during use, the provision of a jack leg to provide counterbalancing support allows for a reduction in the dimensions of the apparatus as a whole. Optionally, the mobile base may comprise a rotatable mount, via which the crane unit is mounted. The provision of a rotatable mount overcomes many of the issues of the gantry crane. Firstly, the rail panel handler can offload or pick up loads which are positioned laterally thereof. This simplifies the steering process for the rail panel handler, since it does not need to move directly to the installation or removal site, but can be side-on to it. Additionally, unorthodox lifting angles can be provided, making movement of non-linear rail panels more achievable. Whilst loading and unloading may be slightly slower than for a gantry crane, due to jack deployment, the ability of the rail panel handler to slew its superstructure relative to the track frame means that it will be quicker overall to perform rail panel handling operations relative to gantry cranes. Preferably, a centre-of-mass of the crane unit may be positioned above the mobile base in at least one relative orientation of the mobile base and crane unit. To ensure that there is no overbalancing of the rail panel handler, it is preferred that the centre-of-mass be positioned over the mobile base at all times when the jack leg is not deployed. In one arrangement, the centre-of-mass of the crane unit may be positioned above the mobile base in all rotational positions of the crane mount with respect to the mobile base. The centre-of-mass of the rail panel handler is preferably directly in line with the axis of rotation of the rotatable mount, so that rotation of the crane unit does not lead to overbalancing, particularly whilst the rail panel handler is laden. Preferably, the jack leg may be positioned at or adjacent to an outboard end of the crane arm. The best position for supporting the load of the crane arm is at the outboard end, thus creating a bridge between the support portion and the jack leg, defined by the crane arm. Optionally, the load carrying device may have an in-use maximum operating vertical position, the jack leg being elevated relative to the said maximum operating vertical position in the in-use non-ground-contacting condition. To avoid impingement of the jack leg onto any load being carried, when it is stowed or retracted, it is desirable for this height to be above the maximum vertical height of the load carrying device, thereby avoiding any collision. Preferably, the load carrying device comprises any or all of: a hook; a bag lifter; or a rail grabber. The ability to use different types of load carrier with the rail panel handler increases the utility of the rail panel handler. Indeed, this allows the rail panel handler to operate as a general utility vehicle capable of handling rail panels and other loads in different circumstances. This significantly reduces the plant expenditure for maintenance and installation businesses. Furthermore, the rail panel handler may have more widespread utility as a general purpose crane and load carrier. Optionally, the crane arm may be a jib crane. The present crane arm operates in the same manner as a jib crane, whilst simultaneously reducing the overall impinging footprint of the crane unit. In a preferred embodiment, the crane arm may be a telescopic crane arm. Telescoping of the crane arm allows the crane arm to be retracted into a most well-balanced condition during transportation, where the centre-of-mass is perfectly aligned to the axis of rotation of the rotatable mount, whilst also providing a much greater operational reach compared with a gantry crane, for instance. The telescopic crane arm may comprise a pair of jib tubes and a central jib tube telescopically extendable relative to the pair of jib tubes. The unique telescoping arrangement of the present crane arm allows for the safe extension of the crane arm over the requisite distance, without sacrificing strength. Optionally, the load carrying device may comprise a guide roller having projections receivably engagable in channels formed between the pair of jib tubes and the central jib tube. The guide roller of the present invention allows for the carriage to operate along the crane arm in the retracted state, to travel the pair of jib tubes, and to travel the central jib tube when extended, without risking lateral instability. Optionally, the load carrying device may be movable along the crane arm. The load carrying device may be movable along the crane arm independently of the telescopic movement of the crane arm. Whilst the load carrying device may be fixed and still functional, movement along the crane arm permits a wider range of lifting and unloading operations to be performed by the rail panel handler, particularly when compared with a gantry crane vehicle. Optionally, the load carrying device may comprise a vertical adjustment mechanism. Raising and lowering of the vertical adjustment mechanism may be important for safely supporting a rail panel in transit, particularly if the load is supported on the crane unit in some form. Preferably, the mobile base may comprise a width-adjustment mechanism to alter a span between tracks or wheels thereof. Adjustment of the width of the mobile base allows for both on- and off-track steering of the rail panel handler, allowing a wider range of functions to be performed in different locations. The crane unit may comprise a support platform at least in part positioned below the crane arm. A support platform allows for safer lifting actions to be performed, as not all of the weight of any load is being supported via the load carrying device during transit, where lateral forces may weaken or damage the device. Preferably, the jack leg may have a width of less than 250mm. Dimensioning of the jack leg in this manner allows for it to be positioned through spaces between sleepers of a rail panel. According to a second aspect of the invention, there is provided a rail panel handling system comprising at least two rail panel handlers in accordance with the first aspect of the invention. Given the size of rail panels, it will be appreciated that at least two rail panel handlers will be required to provide adequate support to a long rail panel, without the risk of toppling. A method of handling a rail panel using a rail panel handler in accordance with the first aspect of the invention, the method comprising the steps of: a] positioning the crane arm of the rail panel handler above a rail panel to be handled; b] adjusting the jack leg into the ground-contacting condition; c] engaging the load carrying device with the rail panel; d] lifting the rail panel using the load carrying device; and e] adjusting the jack leg into the non-ground-contacting condition. Engagement of a rail panel handler in accordance with the invention is different to that of either a standard jib crane or gantry crane. Deployment must be carefully considered to ensure that the jack leg is positioned in a stable configuration, but once done, the present rail panel handler provides a much greater freedom of movement by the user, both in the laden and unladen states. Optionally, during step a], the crane arm may be positioned above the rail panel in an extended state, and further comprising a step subsequent to step d] of retracting the crane arm such that the load carrying device is positioned over the mobile base. The telescoping process here allows for greater control of the load distribution of the rail panel handler, permitting the centre-of-mass to be adjusted before the jack leg support is removed. In such a scenario, the retracting of the crane arm may be performed synchronously with a movement of the mobile base, such that the mobile base moves towards the load carrying device whilst the load carrying device remains stationary. The telescoping in conjunction with steering of the rail panel handler allows for a support to be put into place underneath the rail panel, even where the jack leg has been installed in a gap between sleepers. Preferably, during step a], the rail panel may be spaced apart from the mobile base in a horizontal or substantially horizontal direction. A significant advantage of the present rail panel handler is the ability to move a rail panel off-axis with respect to the base, without overbalancing despite the absence of a large overhanging counterweight. The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows an isometric view from above of one embodiment of a rail panel handler in accordance with the first aspect of the invention; Figure 2 shows an isometric view from the front of the rail panel handler of Figure 1; Figure 3A shows an isometric view from the side of the rail panel handler of Figure 1, with the crane arm in a retracted condition and the jack leg in a retracted condition; Figure 3B shows an isometric view from the side of the rail panel handler of Figure 3A, with the crane arm in an extended condition and the jack leg in an extended condition; Figure 3C shows an isometric view from the side of the rail panel handler of Figure 3B, with the load carrying device in a lowered condition; Figure 4 shows an isometric view from the side of the rail panel handler of Figure 1, with a load support hook provided as the load carrying device; Figure 5 shows an isometric view from the side of the rail panel handler of Figure 4 in an alternative use condition; Figure 6A shows a side viewof a first embodimentof a rail panel handling system in accordance with the second aspect of the invention, the rail panel handling system comprising two rail panel handlers as shown in Figure 1, in a first pre-rail-panel-engagement condition; Figure 6B shows a side view of the rail panel handling system of Figure 6A, in a second pre-rail-panel-engagement condition; Figure 6C shows a side view of the rail panel handling system of Figure 6B, in a first rail-panel-engagement condition; Figure 6D shows a side view of the rail panel handling system of Figure 6C, in a second rail-panel-engagement condition; Figure 6E shows a side view of the rail panel handling system of Figure 6D, in a third rail-panel-engagement condition; Figure 6F shows a side view of the rail panel handling system of Figure 6R, in a fourth rail-panel-engagement condition; Figure 7 shows an isometric view of the rail panel handling system of Figure 6A, in an alternative rail-panel-engagement condition; and Figure 8 shows an isometric view of a second embodiment of a rail panel handling system in accordance with the second aspect of the invention, the rail panel handling system comprising four rail panel handlers as shown in Figure 1. Referring to Figure 1, there is a rail panel handler, indicated globally at 10. The rail panel handler 10 is designed to transport rail panels specifically, but can be used in for the movement of other types of heavy load, as will be discussed in more detail. The rail panel handler 10 comprises a mobile base 12 and a crane unit 14 which is mounted onto the mobile base 12. The mobile base 12 is illustrated as having caterpillar tracks 16, which is common for gantry-style lifting vehicles of this type, but it could easily be provided with wheels or similar movement mechanisms. The crane unit 14 has a support portion 18 which extends at least in part vertically upwards, so as to provide a support structure for a crane arm 20. Here, the crane arm 20 extends out from the support portion 18 over a support platform 22, which extends horizontally from the support portion 18. The support portion 18 is offset relative to a centre of the mobile base 12, such that the crane arm 20 extends over the centre of the mobile base 12, in a cantilevered manner. The centre-of-mass of the rail panel handler 10, in an unladen state, is or is substantially co-axial with a centre of the mobile base 12 in the vertical direction. It is preferred that the centre-of-mass be as low as possible for stability; in the depicted embodiment, this is sufficiently low to allow travel of the rail panel handler 10 safely on gradients up to 43 degrees. A jack leg 24 is provided at or adjacent to an outboard end 26 of the crane arm 20. The jack leg 24 is capable of being extended and retracted between ground-contacting and non-ground-contacting conditions. It is therefore used to support the rail panel handler 10 during a laden state where the centre-of-mass may move. It will be appreciated therefore that the jack leg 24 provides support, and whilst it is preferably positioned at the outboard end 26 of the crane arm 20, there may be many viable support positions it could adopt to create a support condition. The crane arm 20 is preferably telescopically extendable and retractable, for instance, using a hydraulic or pneumatic control system. As such, it is preferred that, even in a most retracted state, the jack leg 24 overhangs the support platform 22 or equivalent lower portion of the crane unit 14, so that there is no risk of collision during retraction. Ideally, the crane arm 20 must be telescopically extendible by approximately 2.4m relative to its retracted length, and this may require a bespoke hydraulic cylinder. The crane arm 20 may be provided so as to have a pair of jib tubes 20a having guide bars facing one another, and a central jib tube 20b having mating side bars to provide the telescope function. Hydraulic cylinders may be located in the jib guides, or could be co-axial with the central jib tube 20b. A load carrying device 28 is provided on the crane arm 20. Here, this is shown as a rail grabber 30, configured to engage with the heads of parallel rails of a rail panel. There may preferably be a carriage 32 or similar translation mechanism for moving the load carrying device 28 along the crane arm 20. It may be feasible to provide a fixed load carrying device 28 however, where it moves in tandem with the telescoping of the crane arm 20. However, this may prove cumbersome, and it is most preferred that a telescopic crane arm 20 is provided with a load carrying device 28 having a translation mechanism which is independently operable of the telescoping. The carriage 32 preferably has specially-shaped guide rollers 34 which allow it to travel on the retracted crane arm 20, as well as the pair of jib tubes 20a on their own, and the central jib tube 20b on its own. The rollers have intermediate guide projections 34a to interface with the channels formed between the pair of jib tubes 20a and the central jib tube 20b. More of the mobile base 12 is visible in Figure 2. The mobile base 12 comprises an inner frame 36 between the caterpillar tracks 16. This inner frame 36 or body may be formed from multiple moving parts, permitting width adjustment of the mobile base 12. Here the track supports 38 positioned either side of the inner frame 36 are translatable in the left and right directions, via a hydraulic actuator, so as to alter the distance between the caterpillar tracks 16. In doing so, this allows the rail panel handler to operate either on existing rail sleepers, or completely spanning existing railway sleepers. This improves the utility of the rail panel handler 10 during maintenance operations. It is preferred that the width adjustment of the mobile base 12 be such that in a narrowest condition, the width of the rail panel handler 10 is less than or equal to the length of a standard sleeper. The mobile base 12 includes a rotatable mount 40, preferably having a full 360° range of motion, and which is connected to the crane unit 14. Preferably, the rotatable mount 40 is connected to an underside of the support platform 22. Control electronics and hydraulics are located inside the support portion 18, which may be conveniently accessible through an access panel 42, most clearly visible in Figure 8. This may include the power module for the rail panel handler 10, and accessibility may allow for modularisation and / or interchange of power modules which may allow for switching between electric or diesel powering, for instance. Figures 3A to 3C show an indicative operational process of the crane arm 20. In a retracted state, as shown in Figure 3A, the crane arm 20 is at its minimum length, and the crane unit 14 is aligned to the mobile base 12. The load carrying device 28 is located above the support platform 22, and the jack leg 24 overhangs the support platform 22. The centre-of-mass of the rail panel handler 10 is vertically above the centre of the mobile base 12, which is also coincident with the rotational centre of the rotatable mount 40. In Figure 3B, the crane arm 20 has been telescopically extended. The outboard end 26 of the crane arm 20 is therefore more distant from the support portion 18. The centre-of-mass is thus moved in the same direction, though in an unladen state, not sufficiently so as to unbalance the rail panel handler 10. However, in preparation for a lifting action, the jack leg 24 is deployed, such that the jack column 44 contacts the ground. This is the ground-contacting condition of the jack leg 24. The change of the centre-of-mass is therefore mitigated by the support provided by the jack leg 24. The rail panel handler 10 is therefore in a state to perform a handling operation without risk of overbalancing. Figure 3C shows the subsequent operation of the handling apparatus. The load carrying device 28 is configured to travel along the crane arm 20, here by movement of a carriage 32 mounted to the crane arm 20 which has a flexible power connector 46 for control. The load carrying device 28 is formed as a main bar 48 having rail contact elements 50 at either end thereof. A support 52 is connected to the main bar 48 which is coupled to the carriage 32 via a winch 54 or similar vertical adjustment mechanism. This permits raising and lowering of the load carrying device 28, either laden or unladen. The load carrying device 28 may thus have an in-use maximum operating vertical position. The jack leg 24 is preferably elevated relative to the said maximum operating vertical position in the in-use non-ground-contacting condition, so as to avoid impingement on the load being carried. Preferably, the rail grabber 30 is removable from the support 52, and may be replaceable with one or more alternative load carrying devices. In Figure 4, the rail panel handler 10 is shown having a bag grab device 30’, formed as a cruciform member onto which bags 56 of, for instance, ballast can be supported. This may be a useful mechanism for transporting heavy materials onsite, via the support platform 22. Figure 5 shows another alternative load carrying device 30”, formed as a hook capable of supporting a reel, such as the cable laying reel 58 indicated. This allows electrical or data cabling 60 to be laid by the rail panel handler 10, further increasing its overall utility. A generalised lifting process is shown in Figures 6A to 6F. Two rail panel handlers 10 are provided, forming a rail panel handling system 100, which approach opposite ends of a rail panel 62. In a normal approach, the crane arm 20 overhangs the support platform 22 so that the jack leg 24 is positioned above the rail panel 62 even before the caterpillar tracks 16 collide with the rail panel 62. This can be seen in Figure 6A. Figure 6B shows the next stage; the telescopic extension of the crane arm 20 over the rail panel 62. This shows the load carrying device 28 travelling with the crane arm 20 during the telescopic extension, and in doing so, it can be seen how the load carrying device 28 is ensured as being correctly positioned above the rail panel 62. Once this is complete, as shown in Figure 6C, the jack leg 24 is deployed into the groundcontacting condition. In this arrangement, the jack leg 24 must be positioned between adjacent sleepers 64 so as to avoid collision therewith. It will be clear that, for this to work, the jack leg 24 itself must be sufficiently narrow to prevent collision. Minimum sleeper separation for a railway track is typically in the range of 300mm to 450mm, and therefore it is preferred that the jack leg 24 have a maximum width less than or equal to 250mm. When the jack leg 24 is in the ground-contacting state, the rail panel handler 10 is fully supported, and the rail grabber 30 of the load carrying device 28 can be engaged with the rails 66 of the rail panel 62. This may be manual or automatic. If the deployment of the jack leg 24 has been successful in stabilising the rail panel handler 10, then lifting of the rail panel 62 may commence, as shown in Figure 6D. Coordinated control between the two rail panel handlers 10 may be necessary to ensure even lifting of the rail panel 62. Once lifted, the rail panel 62 can be brought into a more stable configuration by moving it onto the support platforms 22. However, the position of the jack legs 24 would appear prohibitive to this. The stabilisation can be achieved whilst the rail panel 62 is in a stationary state, by retracting the telescoped crane arms 20 at the same speed as the mobile base 12 advances. In essence, the mobile base 12 drives underneath the rail panel 62 whilst the rail panel 62 is elevated, with both rail panel handlers 10 performing this action synchronously or simultaneously. Figure 6E shows this process in action. Once the support platforms 22 are in place, the rail panel 62 can be lowered by the load carrying devices 28, so as to provide more stable support for the rail panel 62, thereby allowing the jack legs 24 to return to the non-ground-contacting condition, as shown in Figure 6F. The rail panel handlers 10 can then drive the rail panel 62 to the correct location. The load carrying devices 28 remain connected for additional support, though may be detached at this stage. A major advantage of the present rail panel handling system 100, however, is that the rail panel 62 need not necessarily be demounted in the same way in which it is mounted. Figure 7 shows an alternative lifting state of the rail panel handling system 100. Since the rail panel handlers 10 include rotatable mounts 40, the crane units 14 can be rotated relative to the mobile base 12. This can be achieved whilst laden, without causing overbalancing of the rail panel handlers. For instance, if the weight of the rail panel 62 were supported solely by the load carrying devices 28 in the configuration of Figure 6F, then both rotatable mounts 40 can be rotated whilst laden. To prevent overbalancing, the rail grabbers 30 must be positioned directly above the centre-of-mass and / or the rotatable mount 40. The rail panel handlers 10 therefore allow for alternative lifting methods to be achieved. The rotation of the crane units 14 effectively allows for the formation of a jib crane without the need for a significant counterweight overhanging the rear end of the mobile base 12. As can be seen in Figure 7, the support portion 18 and support platform 22 only slightly overhang the caterpillar tracks 16 when in the rotated condition, and therefore infringement on adjacent rail tracks is unlikely. The jack leg 24 allows for outboard lifting of the rail panel 62, since the entire rail panel handler 10 is supported in the direction of lifting with respect to the mobile base 12. It is this aspect that reduces the counterweight requirement with respect to a standard jib crane. This is an operation which is not possible to perform with a gantry crane or a motorised carrier and handling system. It is thus possible to pick up a rail panel 62 using a rail panel handling system 100 where both rail panel handlers 10 are operating within the bounds of an existing railway track 68, as illustrated in Figure 7, and which can, whilst laden, deposit the rail panel 62 to the side of the railway track 68. The reverse is also true; railway panels 62 can be lifted from the side of the railway track 68 without the rail panel handlers 10 needing to dismount from the railway track 68. This greatly improves handling efficiency and manoeuvrability. A further example of a rail panel handling system 200 is shown in Figure 8, which illustrates four rail panel handlers 10 supporting a non-linear track panel 62’, shown as a switch and crossing panel. Since the rail panel handlers 10 are capable of angular positioning of the crane arms 20, the curved portion 70’ of the track panel 62’ can be correctly supported by a rail panel handler 10 without interfering with the steering capability of the rail panel handling system 200. All of the caterpillar tracks 16 are aligned for the rail panel handlers 10, and the rail panel handling system 200 can move as a uniform set. In all instances of the rail panel handlers 10 described, they are operated by remote control, allowing the operator to be positioned at a position of safety away from both the machine and load. This may be achieved by providing a programmable logic controller between a wireless control system and the machine functions. This may allow for future autonomous control means to be provided, for instance, by linking the controls of multiple rail panel handlers 10. The basic functionality of the rail panel handlers could be performed without a rotatable mount. It is the jack arm which provides the outboard counterbalancing to eliminate the large counterweight of a crane jib. However, the combination with the rotatable mount provides for the unique and desirable rail panel loading arrangements. Whilst a caterpillar-tracked apparatus is shown, a wheeled or even rail-mounted machine could be provided. A jack leg is shown in the embodiments illustrated as being directly positioned at the outboard-most end of the crane arm. It will be apparent that the crane arm could slightly overshoot the jack. The primary function of the jack leg is to support the weight of the crane arm, and the skilled person may alter the position thereof based on the rail panel handler as constructed. Equally, a plurality of jack legs could be provided as a means of more evenly distributing the load supported by the crane arm. This may be particularly important for very long crane arms. The rail panel handler could be balanced so that the crane arm need not be telescopic or similarly extendible. However, this may require an increase in the size of the counterweight of the support portion, which may increase the overall bulk of the rail panel handler. It will be appreciated that there is a wide variety of different load carrying devices which are used in the rail handling and maintenance industries, and no specific limitation is intended by the illustrated load carrying devices. It is therefore possible to provide a rail panel handler which has a jack supporting its crane arm, so as to reduce the need for a large counterweight on the vehicle itself. That provides a much greater utility for the rail panel handler compared with existing machines, as there is very limited infringement on other operational rail tracks when performing maintenance operations. Not only that, but the rotatability of the crane unit relative to the mobile base becomes achievable, enabling unorthodox lifting configurations to be achieved which cannot be performed using, for instance, gantry cranes widely used in the industry. The words ‘comprises / comprising’ and the words ‘having / including’ when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps, or components, but do not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

1. A rail panel handler comprising:a mobile base; anda crane unit mounted onto the mobile base, the crane unit comprising:a support portion,a crane arm extending from the support portion,a load carrying device supported by the crane arm suitable for engaging with a rail panel to be handled, anda jack leg connected to the crane arm, the jack leg being adjustable between an in-use ground-contacting condition for lifting a said rail panel, and an in-use non-ground-contacting condition.

2. A rail panel handler as claimed in claim 1, wherein the mobile base comprises a rotatable mount, via which the crane unit is mounted.

3. A rail panel handler as claimed in claim 1 or claim 2, wherein a centre-of-mass of the crane unit is positioned above the mobile base in at least one relative orientation of the mobile base and crane unit.

4. A rail panel handler as claimed in claim 3 when dependent on claim 2, wherein the centre-of-mass of the crane unit is positioned above the mobile base in all rotational positions of the crane mount with respect to the mobile base.

5. A rail panel handler as claimed in any one of the preceding claims, wherein the jack leg is positioned at or adjacent to an outboard end of the crane arm.

6. A rail panel handler as claimed in any one of the preceding claims, wherein the load carrying device has an in-use maximum operating vertical position, the jack leg being elevated relative to the said maximum operating vertical position in the in-use non-ground-contacting condition.

7. A rail panel handler as claimed in any one of the preceding claims, wherein the load carrying device comprises any or all of: a hook; a bag lifter; or a rail grabber.

8. A rail panel handler as claimed in any one of the preceding claims, wherein the crane arm is a jib crane.

9. A rail panel handler as claimed in any one of the preceding claims, wherein the crane arm is a telescopic crane arm.

10. A rail panel handler as claimed in claim 9, wherein the telescopic crane arm comprises a pair of jib tubes and a central jib tube telescopically extendable relative to the pair of jib tubes.

11. A rail panel handler as claimed in claim 10, wherein the load carrying device comprises a guide roller having projections receivably engagable in channels formed between the pair of jib tubes and the central jib tube.

12. A rail panel handler as claimed in any one of the preceding claims, wherein the load carrying device is movable along the crane arm.

13. A rail panel handler as claimed in claim 12 when dependent upon any one of claims 9 to 11, wherein the load carrying device is movable along the crane arm independently of the telescopic movement of the crane arm.

14. A rail panel handler as claimed in any one of the preceding claims, wherein the load carrying device comprises a vertical adjustment mechanism.

15. A rail panel handler as claimed in any one of the preceding claims, wherein the mobile base comprises a width-adjustment mechanism to alter a span between tracks or wheels thereof.

16. A rail panel handler as claimed in any one of the preceding claims, wherein the crane unit comprises a support platform at least in part positioned below the crane arm.

17. A rail panel handler as claimed in any one of the preceding claims, wherein the jack leg has a width of less than 250mm.

18. A rail panel handling system comprising at least two rail panel handlers as claimed in any one of the preceding claims.

19. A method of handling a rail panel using a rail panel handler as claimed in any one of claims 1 to 15, the method comprising the steps of:a] positioning the crane arm of the rail panel handler above a rail panel to be handled;b] adjusting the jack leg into the ground-contacting condition;c] engaging the load carrying device with the rail panel;d] lifting the rail panel using the load carrying device; ande] adjusting the jack leg into the non-ground-contacting condition.

20. A method as claimed in claim 19, wherein, during step a], the crane arm is positioned above the rail panel in an extended state, and further comprising a step subsequent to step d] of retracting the crane arm such that the load carrying device is positioned over the mobile base.

21. A method as claimed in claim 20, wherein the retracting of the crane arm is performed synchronously with a movement of the mobile base, such that the mobile base moves towards the load carrying device whilst the load carrying device remains stationary.

22. A method as claimed in any one of claims 19 to 21, wherein during step a], the rail panel is spaced apart from the mobile base in a horizontal or substantially horizontal direction.

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