Tram systems are becoming increasingly popular for urban public transport. One advantage is that tram networks can be designed so that parts of the route share a carriageway with road vehicles, for example in urban centres where space is very limited, but other parts of the route (for example, longer stretches between towns) can operate effectively as light rail, on track which is separated from road vehicles. Such segregation allows for cheaper construction of the longer runs, since the road does not need to be made up for road vehicles, and allows the trams to avoid any traffic congestion and operate at a higher speed rather than being limited to highway speed limits as they are on shared sections. At the same time, the tram network can directly enter town and city centres, providing direct services to local amenities. Trams can comprise two or more articulated cars, and therefore can provide significantly greater passenger capacity than buses.

However, installation of tram rails on existing roads is costly, time consuming, and often causes significant disruption. Where trams and road vehicles share the same carriageway, the tramway rail must sit flush with the road surface. At the same time, the gauge of the track (i.e. the horizontal distance between the two rails) must be maintained, and the foundation of the track must be sufficiently strong to allow the rails to carry the loads imposed by both tram and highway vehicles.

The most common way of installing tram tracks in a road is to dig up the road and construct a deep concrete foundation. A rail is then put into place, and a continuous concrete upper section is then formed around the rail using a "slip forming" technique or similar. A reasonably long section of road must therefore be closed for the period of time taken to install track.

Systems making use of pre-cast components are known. For example, WO201 1092470 discloses a modular slab system, whereby a track can be installed by laying pre-cast concrete slabs, the slabs having a pair of grooves to allow rails to be installed. In another known system, the rails themselves are pre-cast into modular slabs. However, the cost and disruption involved in installing tramways using these systems is still significant.

It is an object of the invention to provide a rail support means which reduces the cost and disruption required to install a tramway.

Guided bus systems are another known means of providing urban public transport. Typically, a guided bus system utilises buses which can either be steered like an ordinary road vehicle (i.e. by the driver) or alternatively can be put into a guided mode, and steered automatically along a guided busway. This provides a similar advantage as for trams - guided mode can be used for inter-urban sections of the route, where it is possible to segregate the guided buses from other traffic. The guided busways can be narrower than ordinary roads, making it economically and physically feasible to build them in places where a conventional bus lane would not be viable. Also, a made- up road surface is not required over the full width of the guided busway, further reducing cost.

In comparison to tram systems, guided bus systems have the advantage that the vehicles can be operated as conventional buses on any roads which are suitable for conventional buses, without any infrastructure having to be installed. This allows the route to be changed to adapt the service to meet changing demands over time, or to meet the needs of a one-off sporting event, for example. It also means that widespread and lengthy road closures are not required to install a guided bus system. However, a single guided bus vehicle typically has a smaller passenger capacity than a single tram vehicle. At this time, guided bus systems are not as common as trams, and the two systems are generally considered as alternatives rather than complementary. It is a further object of the present invention to provide a combined tramway and busway guide system.

STATEMENT OF INVENTION According to the present invention, there is provided an elongate prefabricated rail support module, the rail support module being connectable longitudinally to a similar module to form a rail support made up of a row of similar rail support modules, for supporting a tram or light rail track, the rail support module having a first longitudinal end face and a second longitudinal end face, the first longitudinal end face being connectable to a second longitudinal end face of a similar module, and the second longitudinal end face being connectable to a first longitudinal end face of another similar module, the first longitudinal end face having a recess, and a resilient sleeve within the recess, for receiving and retaining a portion of a dowel, and the second longitudinal end face having a void for receiving a portion of a similar dowel, when the second longitudinal end face is placed against the first longitudinal end face of a similar module, and a channel provided between the void and an upper face of the module, the channel being suitable for use in introducing a cementitious grout from the upper surface, to fill the void and fix the dowel in place within the void. In a preferred embodiment, the end faces of the rail support modules are substantially flat. However, it will be understood that other shapes, including interlocking formations, may be provided on faces of the rail support modules in some embodiments. Typically, the prefabricated rail support module is pre-cast from reinforced concrete. However, other suitable materials, for example, composites including plastics, may be suitable in some applications.

The rail support module of the invention allows a tram or light rail track to be constructed quickly and with minimal disruption, using components which have been substantially prepared off-site. In particular, the rail support module may be, for example, around 2 metres long. This makes it easy to transport, store and handle on site. At the same time, the connection means using a dowel in a sleeved slot on one module, and in a void filled with cementitious grout in the adjoining module, ensures that load can be transferred longitudinally along the track, despite it being made up from a number of modular sections. The disruption which would be required to install a long length of rail, with slip-form or similarly placed concrete around the rail, is avoided.

Preferably, the dowel is substantially in the form of a plate. The plate may be substantially in the shape of a diamond or square, with an axis of the plate running between opposing corners being substantially in-line with the longitudinal extent of the rail support module, when fitted. In embodiments where the dowel is a plate, the recess and void will be substantially in the form of a slot in each of the first longitudinal end face and the second longitudinal end face. The Permaban (RTM) DD6 plate dowel is found to be suitable in this application. A compressible spacer may be provided on one of the first and second longitudinal end faces, substantially surrounding the dowel when fitted. For example, a compressible spacer may be provided on the first longitudinal end face, substantially surrounding the recess, or alternatively on the second longitudinal end face, substantially surrounding the void. In some embodiments, a compressible spacer may be provided on each of the first and second longitudinal end faces.

The spacer may be for example around 5mm thick, where provided on only one of the two faces.

As metal rails heat and cool, they expand and contract. The compressible spacer between rail support modules allows for this, and ensures that grout is not introduced into the gap between the modules.

The resilient sleeve may be provided integrally with the prefabricated rail support module, for example, cast into a concrete rail support module.

Preferably, a longitudinal groove is provided in the upper face of the rail support module, for receiving a rail. Within the groove, lateral slots may be provided at intervals. The lateral slots are preferably provided in the form of a linear channel, which may be made from steel. The steel channels may be cast into the rail support module during the prefabrication stage. An example of a suitable steel channel is the Halfen (RTM) 250mm HFA-CE 50/30 channel, although other products may be suitable.

As an alternative, the rail may be supported directly on the upper face of the rail support module, without providing a longitudinal groove. In this case, the lateral slots as described above may still be provided, in the upper face of the rail support module. Embodiments with a groove may be used where a tramway is to share the same carriageway as road vehicles. The road surface can be built up to the same level as the upper face of the rail support module. Embodiments without a groove may also in some cases be preferred for tramways on roads, where a continuous pavement surface can be built up, between and around the rails, so that the rails effectively sit in a groove in the pavement surface when the tramway is finished.

When the rail is placed within the longitudinal groove, or directly on a substantially flat upper face of the rail support module as the case may be, it can be retained and accurately adjusted by sliding rail clips within the lateral slots, and then bolting the clips into the lateral slot, preferably on either side of the rail, when the rail is correctly positioned.

Preferably, the rail support module includes at least one threaded socket, on at least one lateral side face of the rail support module. In use, the threaded sockets face inwardly from each of two rails supports of a two-rail track. In some embodiments, therefore, the threaded socket(s) may be provided on both lateral side faces of the rail support module. Alternatively, left- and right- handed versions of the rail support module could be provided, with the threaded socket on the appropriate side. As a further alternative, a track can be constructed using identical rail support modules, each one having the threaded socket on the same side, by rotating the rail support modules on one side of the track. In other words, the rail support modules on one side of the track may have the first ends facing in one direction (e.g. 'up' the track) and the rail support modules on the other side of the track may have the first ends facing in the other direction (e.g. 'down' the track).

The threaded socket(s) on the lateral side face are used to attach tie bars to span laterally between two rail supports of the same two-rail track. The tie bars ensure that the gauge of the track is maintained, but unlike railway sleepers they are not designed to transfer load into the ground - it is the longitudinal rail supports which do this.

In one embodiment, eye bolts are screwed into the threaded sockets, and a tie bar is in turn bolted to the eye bolts, to fix the tie bar between the rail supports of the track. M16 cast-in threaded sockets, and M16 lift suspension eye bolts, are an example of a suitable size.

Rail support modules may be provided which are substantially straight, and also modules may be provided for forming bends in the track. Typically, the track radius of curvature at a bend, measured at a centreline between the two rails making up the track, may be for example 25m or 28m. At a bend, modules of different dimensions for each of the two rails will be needed. For example, in one embodiment, a 25m radius track may have an outer radius, on the outer edge of the outer rail support, of 26.265m, and an inner radius, on the inner edge of the inner rail support, of 23.73m. Clearly, the exact dimensions in different embodiments will depend on the gauge of the track, as well as the width of the support modules and how far they extend either side of the rail.

The rail support module may include a kerb extending from one lateral side of the module, for engaging with the steering mechanism of a guided bus. The kerb is preferably formed in one piece with the rest of the prefabricated rail support module, for example, cast in one piece of reinforced concrete.

Preferably, at least one grouting hole may be provided, the grouting hole extending from an upper face of the rail support module, all the way through the rail support module to a lower face. The grouting hole may be used to introduce grout underneath the rail support module, once the rail support module has been correctly lined-up and levelled, to fix the rail support module in place.

In some embodiments, fixings for adjustable feet, for example threaded sockets, may be provided to assist with levelling the rail support modules. As an alternative, jacks and spacers may be used to level the support modules, before final grouting to fix in place.

According to another aspect of the invention, there is provided a rail support made up of a row of rail support modules, each rail support module according to the first aspect of the invention, the first longitudinal face of each rail support module adjoining the second longitudinal face of an adjacent rail support module, with a dowel fitted into the recess of each first longitudinal face, and extending into the void of the adjoining second longitudinal face, and a cementitious grout filling each void and substantially surrounding the dowel.

According to a further aspect of the invention, there is provided a two-rail track support made up of two laterally-spaced rows of rail support modules, the rows running substantially parallel to each other, and tie bars fixed between inner faces of the rail support modules for maintaining the lateral spacing between the two rows of rail support modules.

In another aspect of the invention, there is provided a track for a tram, comprising the two-rail track support, with a rail fitted to each rail support.

According to a further aspect of the invention, there is provided a method of joining a first rail support module of the first aspect of the invention longitudinally to a similar second rail support module, to form a rail support made up of a row of similar rail support modules, the method comprising the steps of: inserting a dowel into the resilient sleeve of the recess of the first longitudinal end face of the first rail support module; positioning the first and second rail support modules such that the first longitudinal end face of the first rail support module is facing the second longitudinal end face of the second rail support module, and the dowel which was inserted into the resilient sleeve of the recess is extending into the void in the second longitudinal end face of the second rail support module; introducing a cementitious grout from the entrance to the channel in the upper surface of the second rail support module, to fill the void of the second rail support module and fix the dowel in place within the void.

When the dowel is inserted into the resilient sleeve, the sleeve may deform around the dowel in order to retain the dowel in the recess.

It will be appreciated that the method of the invention may be repeated to make a rail support of substantially any length, by joining multiple rail support modules together according to the method.

The method may optionally include the step of placing a compressible spacer between the first longitudinal end face of the first rail support module and the second longitudinal end face of the second rail support module.

According to another aspect of the invention, there is provided a tram or light rail track, comprising: a sub-base; a pair of rails; a pair of rail supports, each rail support being provided between a rail and the sub-base, for transferring the load of a tram or light rail vehicle from the rail into the sub-base; and tie bars spanning laterally between the rail supports, above the sub-base, for maintaining a fixed lateral distance between the rail supports; and fixing means for fixing each rail in position on a respective rail support.

In the invention, the load of the tram or light rail vehicle is transferred to the sub-base via elongate rail supports, which run substantially along the length of each rail, underneath the rail between the rail and the sub-base. Sleepers, or other load-bearing components between the rails, are not required. The tie bars are loaded only horizontally, and serve to maintain the gauge of the track.

Preferably, the rail supports are made from reinforced concrete. In some embodiments, the rail supports may be provided in prefabricated modular sections. The modular sections may be longitudinally connected to each other as described above, or alternatively may be connected by other means. Separately, the tie bars may be attached to the rail supports substantially as described above, irrespective of whether or not the above described longitudinal connection is used. Rail supports may be provided in versions having the rail running within a channel on the upper surface, or not, having lateral slots for receiving rail clips to retain the rails, or may independently have any other of the features already described.

In one embodiment, the requirement for the sub-base is for a minimum surface modulus of 80MPa. A cementitious grout may be provided to surround the rail supports, and fix them in position on the sub-base. According to another aspect of the invention, there is provided a method of constructing a track for a tramway or light railway, the method comprising the steps of: providing a sub-base; placing a pair of prefabricated elongate rail supports on the sub-base; fixing tie bars laterally between the elongate rail supports, to fix the lateral distance between the elongate rail supports; levelling the rail supports and introducing a cementitious grout beneath and around the rail supports, to fix the rail supports in place on the sub-base; installing a rail on each rail support. The prefabricated rail supports may be pre-cast in reinforced concrete.

The sub-base may be a suitable sub-base for providing a minimum surface modulus of 80MPa. Where a sub-base is constructed for the purpose, it will typically consist of compacted hardcore. However, one advantage of the apparatus and method of the invention is that, for construction of a tramway in-street, it may be possible to excavate channels for the rails by removing small portions of the existing road surface, and make use of an existing sub-base. In some areas, the sub-base of the road may comprise bound bitumen layers, or other materials, and as long as this provides a suitable surface modulus, it should be suitable for use, without having to construct a new sub-base. The prefabricated elongate rail supports may be provided in the form of multiple rail support modules, connected together longitudinally. The rail support modules may have any of the features described above, and may be connected together according to the method set out above. The tie bars are preferably made from steel, and are preferably fixed between the rail supports as described above, with threaded sockets cast into the rail supports, eye bolts in the threaded sockets, and then steel tie bars bolted to the eye bolts.

In some embodiments, adjustable feet may be provided on the rail supports to aid levelling. Alternatively, the rail supports may be levelled with jacks and packed with material before grouting.

The rail may be fixed to the rail support with clips fixed within lateral slots, as described in more detail above.

Further grout may be introduced around the rail, which may either be installed within a longitudinal channel in the rail support, or on a substantially flat upper face of the rail support. Optionally, a final pavement surface may be laid on top of and/or around the rail supports, where the track will be shared by both road and rail vehicles, for example in a tram system.

According to another aspect of the invention, there is provided an elongate prefabricated rail support for transferring load between a rail fixed along an upper surface of the rail support, and a sub-base underneath the rail support, the prefabricated rail support including a kerb extending upwardly from its upper surface, the kerb providing a substantially vertical wall adjacent a section of the upper surface, for engaging the steering mechanism of a guided bus. The prefabricated support is preferably made from pre-cast reinforced concrete.

The prefabricated rail support with an integrated kerb provides a combination solution for allowing both trams and guided buses to be operated along the same passage. The rail support may have any of the features described above, and may be installed according to the methods described above. In this way, a combination tramway and guided busway can be efficiently built, allowing trams and guided buses to travel along the same route. At either end of the combination tramway and guided busway, the tramway may continue along roads shared with cars and other vehicles, and guided buses (operating with the driver steering) may travel along any suitable existing roads, without the need for special infrastructure to be installed. Trams may be used for higher-capacity routes, where a large number of passengers need to be carried, and guided buses may be used to service lower capacity routes, or routes which are only in demand on an ad-hoc basis, for example for special events. The known advantages of tram systems and guided bus systems can therefore be combined, and a section of combination track, for high-speed operation segregated from other vehicles, can be provided at low cost, compared with traditional ballasted track which is suitable only for trams.

According to another aspect of the invention, there is provided an elongate prefabricated rail support having an upper surface for fixing a rail along the rail support, the upper surface of the rail support having lateral slots provided at intervals. The prefabricated support may be made from pre-cast concrete. The lateral slots are preferably each provided in the form of a linear channel, which may be made from steel, which is integrated into the prefabricated support at manufacture, e.g. cast into the concrete rail support module during the precasting stage. An example of a suitable steel channel is the Halfen (RTM) 250mm HFA-CE 50/30 channel, although other products may be suitable.

When the rail is placed on the upper face of the rail support module (in some embodiments the rail may be placed within a groove on the upper surface), it can be retained and accurately adjusted by sliding rail clips within the lateral slots, and then bolting the clips into the lateral slot, preferably on either side of the rail, when the rail is correctly positioned.

The prefabricated rail support may be made from a plurality of connected rail support modules, as described in detail above. Any of the above-described features may independently be provided in the prefabricated rail support of this aspect of the invention.

According to another aspect of the invention, there is provided a method of constructing a track for a tramway or light railway, the method comprising the steps of: providing a sub-base; placing a pair of prefabricated elongate rail supports on the sub-base, each of the prefabricated elongate rail supports having an elongate support surface on an upper face for supporting a rail, and a plurality of slots provided laterally across the support surface, at intervals along the support surface; placing a rail on the support surface of each rail support; installing a rail clip on either side of the rail, in each of the lateral slots, adjusting the position of the clip to hold the rail in the correct position, and then fixing each clip into the slot, for example with bolts.

The prefabricated support may be pre-cast from concrete.

The method of installing a rail on a rail support allows for very fine adjustability of the rail position, in order to achieve the correct gauge of track quickly and easily. The adjustability allows a greater tolerance when laying the rail supports themselves, since the lateral distance between the rail supports is not completely relied upon in order to achieve the correct track gauge. DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show more clearly how it may be carried into effect, example embodiments will now be described with reference to the accompanying drawings, in which: Figure 1 a is a cross section through a pair of rail support modules in accordance with the invention, in the process of being joined together;

Figure 1 b shows the rail support modules of Figure 1 , at a more advanced stage of the joining process;

Figure 2 is a cross section through a track support, comprising two rows of the rail support modules of Figure 1 ;

Figure 3 is a cross section through a rail support comprising a row of the rail support modules of Figure 1 , with a rail installed;

Figure 4 is a cross section through a rail support comprising a row of an alternative rail support module, which also includes a kerb for guiding a guided bus; and Figure 5 is a plan view from above of a pair of rail support modules, forming a section of track support for a two-rail tram or train track.

DESCRIPTION OF EMBODIMENTS

Referring firstly to Figures 1 a and 1 b, two identical rail support modules are indicated at 10 and 10'. Only part of each rail support module is shown, but each module has a first end and a second end. In Figure 1 , the first end of module 10 and the second end of module 10' are visible. The first end of each module includes a recess 12 in the form of a slot. The recess is lined with a resilient sleeve 14. The resilient sleeve may be made from, for example, plastics, and may deform slightly when a dowel is forced into the slot, so that the dowel is gripped within the slot by the sleeve 14. A compressible spacer 16 is provided, on the first end face of the module 10, substantially surrounding the recess 12.

In Figure 1 , a dowel 18 has been inserted into the recess 12. The dowel is substantially in the form of a plate. For example, a Permaban (RTM) DD6 plate dowel may be suitable in some embodiments. The plate dowel is substantially square or diamond shaped, and an axis of the dowel running between two corners is substantially in line with the longitudinal extent of the module 10 (i.e. running horizontally across the page in Figure 1 ).

Once the dowel is inserted, the second rail support module 10' is placed against the first rail support module 10, with the second longitudinal end face of the second rail support module 10' facing the first longitudinal end face of the first rail support module 10. The second rail support module is moved as shown by arrow A to bring it into this position. In particular, a void 20 which is provided in the form of a slot in the second longitudinal end face of the rail support module 10' is introduced over the protruding part of the dowel 18. Figure 1 b shows the same two rail support modules 10, 10', once they have been brought into position ready for fixing. The dowel 18 is now positioned partly in the recess 12 of the first rail support module 10 and partly in the void 20 of the second rail support module 10'. A channel 22 runs through the rail support module, from an upper face of the rail support module through to the void 20. This channel is used to introduce a cementitious grout to fill the void 20 around the dowel 18, and fix the dowel in place, and therefore join the two rail support modules together so that load can be transferred longitudinally between them. Preferably, the channel 22 as well as the void 20 is filled with grout. Once filled, the grout in the channel and void may be stirred or agitated to remove any air pockets, and then the grout level topped up. Grout filled to the top of the channel 22 is a good visual indication that this has been done correctly.

This process can be repeated to make a continuous row of rail support modules to support a rail for a tram or light rail vehicle. Referring now to Figure 2, two rail supports 24, 24' are shown running parallel to each other, to support rails of a two-rail train or tram track. Each rail support 24, 24' is made up of a row of rail support modules, joined together longitudinally as described above and shown in Figures 1 a and 1 b.

Each rail support 24, 24' includes threaded sockets 26, cast into a side face of the rail support 24, 24'. The threaded sockets 26 are cast into the reinforced concrete structure of the rail support modules during the pre-casting process. In one embodiment, each rail support module has two threaded sockets 26 cast into one side face, and each module is about 2m long. Therefore, the threaded sockets are spaced apart by around 1 m in the finished rail support made up from multiple rail support modules.

An eye bolt 28 is screwed into each of the threaded sockets 26. The eye bolts are positioned so that the plane of the "eye" is substantially horizontal in use and as shown in Figure 2. A steel tie bar 28 is then bolted between opposing eye bolts, screwed into the parallel rail supports 24, 24'. It will be noted that, with the rail supports 24, 24' resting on a sub-base to transfer load between a rail and a sub-base, the steel tie bar 28 is above the sub-base, and therefore does not operate to transfer load into the sub- base, but only to maintain the gauge of the track, i.e. the horizontal distance between the two rail supports 24, 24'. Figure 3 shows how a rail 30 is fixed in place on an upper surface of a rail support 24. In this embodiment, the rail support includes a longitudinal channel 32 on its upper surface. The rail is installed in the channel 32 so that the top of the rail sits substantially flush with the upper surface of the rail support, where it surrounds the rail. This is ideal for installing tram lines in areas where the tram will share a road with road vehicles. Figure 3 is a cross-section through the rail support 24, at a point where a lateral slot 34 is provided in the upper surface of the rail support 24. The lateral slot is in the form of a linear steel channel, for example the Halfen (RTM) 250mm HFA-CE 50/30 channel, and is cast into the reinforced concrete rail support 24 during pre-casting. A rail clip 34 can be positioned in the lateral slot 34, at either side of the rail 30, and the rail clips 34 can then be moved laterally as indicated by arrow B, in order to adjust the lateral position of the rail 30 on the rail support 24. When the rail 30 is correctly positioned, the rail clips 34 may be bolted in place within the lateral slot 34.

Figure 4 is a cross-section through another embodiment of a rail support module 36. In Figure 4, internal rebars of the reinforced pre-cast concrete of the rail support module 36 are visible. The rail support module 36 has similar features to the above described rail support modules, for example the longitudinal connecting arrangement shown in Figures 1 a and 1 b, the threaded sockets for connecting lateral tie bars as shown in Figure 2, and the lateral slots for adjusting and fixing a rail with clips as shown in Figure 3. The embodiment of Figure 4 additionally includes a kerb 38 for engaging with the steering mechanism of a guided bus. The kerb 38 is provided as an integral part of the pre-cast reinforced concrete structure of the rail support module 36. When multiple similar rail support modules 36 are assembled to form a track support comprising two substantially parallel rows of longitudinally joined and laterally tied rail support modules 36, and a rail fitted, the resulting track is suitable for use as a combination tramway and guided busway.

Figure 5 is an overhead view of a section of the track support shown in cross section in Figure 2. The length shown is the length of a single module on either side, but it will be understood that in practice a track support will comprise multiple modules on either side. The diamond-shaped plate dowels 18 are seen protruding from the first longitudinal end face of each of the rail support modules 24, 24', ready for the installation of further rail support modules 24, 24' to lengthen the track. In Figure 5, the spacing of the lateral slots 34 is clearly shown, with two lateral slots on each rail support module 24, 24', at around a quarter and three-quarters of the way along each module, so that when multiple modules are connected together longitudinally the slots 34 will repeat at an interval of around half the length of the module (e.g. about every 1 m in this embodiment).

It will be noted that, in this embodiment, the rail support modules 24, 24' are arranged with their first longitudinal faces facing in the same direction along the track, that is, down the page in Figure 5. To facilitate this, a left-hand rail support module 24 is provided with the threaded sockets 26 along its right hand face (as shown in Figure 5), and a right-hand rail support module 24' is provided with the threaded sockets 26 along its left-hand face. This allows the first longitudinal faces to face in the same direction along the track, with the threaded sockets being always on the inner face of the rail support modules 24, 24'. As an alternative, threaded sockets may be provided on both faces to make a universal rail support module which can be fitted either way around. A further alternative is to position the tracks so that the first longitudinal faces of the rail support modules on one side face one way along the track, and the first longitudinal faces of the rail support modules on the other side face the other way along the track.

A grouting hole 40 is provided in each rail support module 24, 24', substantially centrally through each rail support module 24, 24' from the upper surface through to the lower surface of each rail support module. The grouting hole in this embodiment is a circular hole of around 75mm diameter. When the rail support modules have been aligned and levelled, grout is introduced underneath the rail support modules 24, 24' through the hole 40, to fix the rail support modules in place.

The embodiments described above are provided by way of example only, and various changes and modifications will be apparent to persons skilled in the art without departing from the scope of the present invention as defined by the appended claims.