Railway sleeper apparatus and railway track

Abstract

A railway sleeper system comprising a spaced apart first rail support 2 and a second rail support 3. Each rail support comprises a post-tensioning mechanism 4 comprising an aperture 5 passing through the respective rail support and a tensioning bar 6 removably located within the aperture and fixed in place at a first and second fixture 11, 12. The bar is held under extension between the first fixture and second fixture. The fixture may be an anchoring system comprising a nut 9, screw thread 16 and bearing plate 8. The sleeper may be formed of concrete. The bar may be formed from steel. There may be a base layer 61, an unreinforced slab 62 on the base layer, and a plurality of railway sleepers located on the slab, wherein ballast 63 is provided between the first and second support member of the sleeper.

Description

The present invention relates to a railway sleeper apparatus and a railway track comprising a plurality of such railway sleeper apparatus. Traditional railway tracks are either ballast tracks or so-called ballastless tracks. Ballast tracks comprise a base layer of earth, a large ballast layer of crushed stone, and concrete sleepers arranged at spaced intervals in the top of the ballast layer. A ballast track is elastic in the sense that the ballast layer allows for a degree of movement of the sleepers under loading. The load is transferred from the rails through the sleepers and then distributed into the ballast layer. The advantage of this design is a low construction cost, but a disadvantage is a high maintenance cost. Ballastless tracks comprise a reinforced concrete layer set into the desired location, to which concrete ties or sleepers are fixed. The concrete layer is usually inelastic, and elasticity is provided by flexibility between either the rails and the concrete ties or sleepers, or between the ties or sleepers and the concrete slab, as well inherent elasticity within the conglomerate of the tie or sleeper. The advantages of a ballastless track over a traditional ballast track are its highly consistent track geometry, longer life span, and the reduced need for maintenance. The main disadvantage is a high construction cost. A particular problem with both ballast tracks and ballastless tracks is low recyclability. With a ballast track the concrete sleepers are commonly cast around a bundle of steel wires twisted together, which are held under extension as the concrete sets. The pre-tension prestressed wires enhance the efficiency and longevity of the concrete sleepers because they prevent cracks by applying an internal compression force. However, at the end of the life of the railway track it is complex and expensive to remove the steel wires from the concrete, and this is therefore not performed for economic reasons. As such, all the steel is disposed of together with the concrete sleepers which is wasteful as the steel is recyclable. Ballastless track also suffer from low recyclability due to the much larger amount of concrete and steel involved. The present invention is intended to overcome some of the above described problems. Therefore, according to a first aspect of the present invention railway sleeper apparatus comprises a first rail support member and a second rail support member spaced apart from said first rail support member, in which said first rail support member comprises a first post-tensioning mechanism comprising a first aperture passing through said first rail support member and a first tensioning bar removably located therein with a first end thereof fixed to said first rail support member by a first fixture and a second end thereof fixed to said first rail support member by a second fixture, and in which said first tensioning bar is held under extension between said first fixture and said second fixture. Thus, the first aspect of the present invention provides a railway sleeper apparatus comprising two discrete support members rather than a single unit, which reduces the amount of material required compared to a traditional railway sleeper. In addition, the first rail support member has a post-tensioned arrangement which provides the necessary support for the desired longevity and efficiency, but which can be readily disassembled. The first tensioning bar can be removed from the first aperture at the end of the life of the railway sleeper apparatus, and recycled accordingly. The arrangement is post-tensioned in the sense that the tension is applied to the first rail support member after it has been cast and set. The first rail support member and the second rail support member can be spaced apart along a lateral axis of the railway sleeper apparatus, and the first aperture can extend in the direction of the lateral axis. Hence, with the lateral extent of the railway sleeper apparatus normal to the direction of the rails, the tensioning provided to the first rail support member is also normal thereto. The first fixture can comprise any known mechanism capable of fixing the first end of the first tensioning bar to the first rail support member. However, in a preferred construction the first fixture can comprise a first anchor system abutting against a first side of the first rail support member. The first anchor system can be axially movably locatable relative to the first tensioning bar, so as to provide for the first tensioning bar to be placed under extension. Likewise the second fixture can comprise a second anchor system abutting against a second side of the first rail support member, and the second anchor system can also be axially movably locatable relative to the first tensioning bar. In order to provide for the above, the first tensioning bar can comprise a first screw thread formed in the first end thereof and a second screw thread formed in the second end thereof. The first anchor system can comprise a first bearing plate located on the first tensioning bar and a first nut located on the first screw thread. The second anchor system can then comprise a second bearing plate located on the first tensioning bar and a second nut located on the second screw thread. With this construction the first tensioning bar can be placed in the first aperture with the first end and second end thereof protruding from each end. The first bearing plate and the second bearing plate are then mounted to the first tensioning bar and placed against the first side and second side of the first support member respectively. The first nut and second nut are screwed onto the first screw thread and second screw thread respectively, and tightened in order to drive the first bearing plate and second bearing plate against the first side and second side of the first support member, in order to provide the post-tensioning. This is a simple and effective construction which is easy to manufacture and easy to dismantle. The second rail support member can be like the first. Namely, it can comprise a second post-tensioning mechanism comprising a second aperture passing through the second rail support member in the direction of the lateral axis, and a second tensioning bar can be removably located therein with a first end thereof fixed to the second rail support member by a third fixture and a second end thereof fixed to the second rail support member by a fourth fixture. The second tensioning bar can also be held under extension between the third fixture and the fourth fixture. The third fixture can comprise a third anchor system abutting against a first side of the second rail support member, and the third anchor system can be axially movably locatable relative to the second tensioning bar. Likewise, the fourth fixture can comprises a fourth anchor system abutting against a second side of the second rail support member, and the fourth anchor system can also be axially movably locatable relative to the second tensioning bar. The second tensioning bar can comprise a third screw thread formed in the first end thereof and a fourth screw thread formed in the second end thereof. The third anchor system can comprise a third bearing plate located on the second tensioning bar and a third nut located on the third screw thread. Likewise, the fourth anchor system can comprise a fourth bearing plate located on the second tensioning bar and a fourth nut located on the fourth screw thread. In a preferred construction the first rail support member and the second rail support member can be located a pre-determined distance apart such that they support a pair of parallel rails with which they are used a track gauge distance apart. The gauge of the track will be for the skilled person to determine, but will be any of the known gauge widths. In order to facilitate the above a connecting rod can be mounted between the first rail support member and the second rail support member such that they are located the predetermined distance apart. The connecting rod can be a T-shaped beam with its transverse portion lowermost, which can then be attached to the first support member and the second support member by bolts passing therethrough. As such, the connecting rod can be readily removed from the railway sleeper apparatus at the end of its life for recycling. Preferably the first rail support member can comprise one or more further first posttensioning mechanisms of the same construction as the first post-tensioning mechanism described above, and arranged parallel thereto. In one embodiment three such first posttensioning mechanisms can be provided. Likewise, the second rail support member can also comprise one or more further second post-tensioning mechanisms of the same construction as the second post-tensioning mechanism described above, and arranged parallel thereto. Again, three such second post-tensioning mechanisms can be provided. The first rail support member and the second rail support member can be made from any suitable material, but preferably they are made from concrete. The first tensioning bar and the second tensioning bar can be made from any suitable material, but preferably they are made from steel. The first rail support member and the second rail support member are preferably made in a range of between 50kg and 70kg in weight, depending on the use requirements. In a preferred construction they are substantially 57kg in weight. The first tensioning bar and the second tensioning bar can have a diameter in the range of 10mm to 30mm, depending on the use requirements. In a preferred construction they are substantially 16mm in diameter, and can have an ultimate stress rating of 1030MPa. A typical bar of this type is the FREYSSIBAR (RTM) manufactured by the company Freyssinet (RTM). The post tension stress on the bar is typically set to substantially 85% of its ultimate stress level, so for instance 875MPa. This is adjusted by tightening or loosening the first nut and / or second nut. It will be appreciated that while the railway sleeper apparatus described above can be manufactured and sold as such, they have no real application outside of a railway track. Therefore, according to a second aspect of the present invention a railway track comprises a base layer, a slab located on the base layer and a plurality of railway sleeper apparatus as claimed in claim 1 below, which are located on the slab at spaced intervals. The railway track further comprises ballast material surrounding the first rail support member and the second rail support member of each railway sleeper apparatus. Thus, the second aspect of the present invention provides a hybrid railway track construction comprising features of both ballast tracks and ballastless tracks. Firstly, unlike a ballast track the railway track comprises a slab on which the railway sleeper apparatus are located. This slab provides accurate levelling of the railway sleeper apparatus, and underlying support for the discrete first rail support member and second rail support member to prevent any bending of the railway sleeper apparatus as a result of irregular loading between the first rail support member and second rail support member in use. A traditional railway sleeper does not suffer from such bending as it is a single reinforced unit designed to take such irregular loading. The slab also distributes the loading to the base layer underneath more evenly than traditional sleepers distribute the loading to the ballast underneath them, because it is a continuous layer as opposed to spaced sleepers. The kinds of discrete rail ties commonly used in ballastless tracks use a similar arrangement to the slab in order to provide linear support between them, in the form of the reinforced concrete layer to which they are fixed. However, the slab of the second aspect of the present invention does not need to be as substantial in size and strength as the reinforced concrete layer of a ballastless track, as the loading it supports is far less than that with a ballastless track, due to the loading absorbed by the post-tensioned first rail support member and second rail support member. The slab can therefore be made from far cheaper unreinforced concrete. Preferably it can be only 100mm thick. Secondly, like a ballast track the railway track of the second aspect of the present invention does employ ballast to provide lateral support and elasticity to the railway sleeper apparatus. This arrangement therefore employs the same beneficially low installation cost of traditional ballast track compared to ballastless track, where a heavy reinforced concrete layer is used to provide all the support. Ballast is relatively easy to procure and to install, and it provides the necessary level of lateral support in this case. However, due to the inherent strength of the first rail support member and the second rail support member, and the fact that they present twice the lateral surface area to the ballast compared to a traditional railway sleeper, far less ballast is actually required compared to in a traditional ballast track. This significantly reduces the installation cost, and recycling required. In effect, the ballast located between the discrete first rail support member and second rail support member provides that additional level of lateral support. Some of the loading may be transferred from the first rail support member to the second rail support member through the ballast in use, and vice versa, but most of it is absorbed by the ballast. So, the smaller discrete first rail support member and second rail support member, the lighter unreinforced slab and the lower quantity of ballast required, all means that the hybrid railway track of the second aspect of the present invention uses far less concrete and steel than traditional ballast and ballastless tracks. It is estimated that the railway track will use about 25% of the ballast commonly required for a ballast track, and only 40% of the concrete required for a ballastless track, while still providing the same level of support performance. It can then be far more readily dismantled into its constituent parts for recycling. None of the concrete parts have any embedded steel which cannot be separated therefrom. The invention can be performed in various ways, but two embodiments will now be described by way of example, and with reference to the accompanying drawings, in which: Figure 1 is a cross sectional split side view of a railway sleeper apparatus according to a the first aspect of the present invention; Figure 2 is a split plan view of the railway sleeper apparatus as shown in Figure 1; Figure 3 is a side view of the railway sleeper apparatus as shown in Figure 1; Figure 4 is a cross-sectional side view of a railway track according to the second aspect of the present invention; Figure 5 is a partial cross-sectional side view of the railway track as shown in Figure 4; Figure 6 is a partial plan view of the railway track as shown in Figure 4; and, Figure 7 is an end view of the railway sleeper apparatus as shown in Figure 1. As shown in Figure 1, a railway sleeper apparatus 1 comprises a first rail support member 2 and a second rail support member 3 spaced apart from the first rail support member 2. The first rail support member 2 comprises a first post-tensioning mechanism 4 comprising a first aperture 5 passing through the first rail support member 2 and a first tensioning bar 6 removably located therein with a first end 7 thereof fixed to the first rail support member 2 by a first fixture, in the form of first bearing plate 8 and first nut 9. A second end 10 of the first tensioning bar 6 is fixed to the first rail support member 2 by a second fixture, in the form of second bearing plate 11 and second nut 12. As explained further below, the first tensioning bar 7 is held under extension between first bearing plate 8 and the second bearing plate 11. As is clear from Figures 1 and 3 the first rail support member 2 and the second rail support member 3 are spaced apart along a lateral axis A-A of the railway sleeper apparatus 1, and the first aperture 5 extends in the direction of the lateral axis A-A. As explained below, with the lateral extent of the railway sleeper apparatus 1 normal to the direction of the rails 13, the tensioning provided to the first rail support member 1 is also normal thereto. The first bearing plate 8 abuts against a first side 14 of the first rail support member 2. The first bearing plate 8 is axially movably locatable relative to the first tensioning bar 6, by virtue of the first tensioning bar 6 passing freely through first opening 15 in the first bearing plate 8. This relative movement provides for the first tensioning bar 7 to be placed under extension. Namely, the first end 7 of the first tensioning bar 6 comprises a first screw thread 16, and the first nut 9 is screwed onto it. Hence, rotation of the first nut 9 onto the first screw thread 16 increases the pressure between the first bearing plate 8 and the first side 14 of the first rail support member 2. With the second end 10 of the first tensioning bar 6 fixed in place this increase in pressure subjects the first tensioning bar 6 to an extension force, and therefore the first rail support member 2 to a compression force. Likewise the second bearing plate 11 abuts against a second side 17 of the first rail support member 2. The second bearing plate 11 is axially movably locatable relative to the first tensioning bar 6, by virtue of the first tensioning bar 6 passing freely through second opening 18 in the second bearing plate 11. This relative movement provides for the first tensioning bar 7 to be placed under extension. Namely, the second end 10 of the first tensioning bar 6 comprises a second screw thread 19, and the second nut 12 is screwed onto it. Hence, rotation of the second nut 12 onto the second screw thread 19 increases the pressure between the second bearing plate 11 and the second side 17 of the first rail support member 2. With the first end 7 of the first tensioning bar 6 fixed in place this increase in pressure subjects the first tensioning bar 6 to an extension force, and therefore the first rail support member 2 to a compression force. It will be appreciated that the first tensioning bar 6 can therefore be placed under extension by tightening the first nut 9 and / or the second nut 12. By having the same arrangement at each end of the first tensioning bar 6 the compressive loading applied to the first nut 9 and first bearing plate 8, and to second nut 12 and second bearing plate 11 by the post-tensioned first tensioning bar 6 is shared. The second rail support member 3 is the same as the first support member 2. Namely, it comprises a second post-tensioning mechanism 20 comprising a second aperture 21 passing through the second rail support member 3 in the direction of the lateral axis A-A, and a second tensioning bar 22 removably located therein with a first end 23 thereof fixed to the second rail support member 3 by a third fixture, in the form of third bearing plate 24 and third nut 25. A second end 26 of the second tensioning bar 22 is fixed to the second rail support 3 member by a fourth fixture, in the form of fourth bearing plate 27 and fourth nut 28. The second tensioning bar 22 is held under extension between the third bearing plate 24 and the fourth bearing plate 27. The third bearing plate 24 abuts against a first side 29 of the second rail support member 3. The third bearing plate 24 is axially movably locatable relative to the second tensioning bar 22, by virtue of the second tensioning bar 22 passing freely through third opening 30 in the third bearing plate 24. This relative movement provides for the second tensioning bar 22 to be placed under extension. Namely, the first end 23 of the first tensioning bar 22 comprises a third screw thread 31, and the third nut 25 is screwed onto it. Hence, rotation of the third nut 25 onto the third screw thread 31 increases the pressure between the third bearing plate 24 and the first side 29 of the second rail support member 3. With the second end 26 of the second tensioning bar 22 fixed in place this increase in pressure subjects the second tensioning bar 22 to an extension force, and therefore the second rail support member 3 to a compression force. Likewise the fourth bearing plate 27 abuts against a second side 32 of the second rail support member 3. The fourth bearing plate 27 is axially movably locatable relative to the second tensioning bar 22, by virtue of the second tensioning bar 22 passing freely through fourth opening 33 in the fourth bearing plate 27. This relative movement provides for the second tensioning bar 22 to be placed under extension. Namely, the second end 26 of the second tensioning bar 22 comprises a fourth screw thread 34, and the fourth nut 28 is screwed onto it. Hence, rotation of the fourth nut 28 onto the fourth screw thread 34 increases the pressure between the fourth bearing plate 27 and the second side 32 of the second rail support member 3. With the first end 23 of the second tensioning bar 22 fixed in place this increase in pressure subjects the second tensioning bar 22 to an extension force, and therefore the second rail support member to a compression force. It will be appreciated that the second tensioning bar 22 can therefore be placed under extension by tightening the third nut 25 and / or the fourth nut 28. By having the same arrangement at each end of the second tensioning bar 22 the compressive loading applied to the third nut 25 and third bearing plate 24, and to fourth nut 28 and second bearing plate 27 by the post-tensioned second tensioning bar 22 is shared. The first rail support member 2 and the second rail support member 3 are made from cast concrete and are 57kg in weight. The first aperture 5 and the second aperture 21 are formed during construction of the first rail support member 2 and the second rail support member 3 respectively, by placing first sleeve 35 and second sleeve 36 respectively in the casting mould and pouring the liquid concrete around them. The first tensioning bar 6 and the second tensioning bar 22 are made from steel, are 16mm in diameter and have an ultimate stress rating of 1030MPa. A typical bar of this type is the FREYSSIBAR (RTM) manufactured by the company Freyssinet (RTM). The posttension stress applied to the first tensioning bar 6 and the second tensioning bar 22 by tightening the first nut 9 and / or second nut 12, and the third nut 25 and / or fourth nut 28 respectively, as described above, is to substantially 85% of the ultimate stress level, namely 875MPa. As shown in Figure 2 the first rail support member 2 comprises two further first posttensioning mechanisms 37 and 38 of the same construction as the first post-tensioning mechanism 4 described above, and arranged parallel thereto. Therefore, the post-tensioning applied to the first rail support member 2 is applied across its extent. Referring to Figure 7, the first bearing plate 8 is square in shape, and covers only slight less than a third of the surface area of the first side 14 of the first rail support member 2. Likewise, the first bearing plates 8’ of the two further first post-tensioning mechanisms 37 and 38 are the same shape as the first bearing plate 8, and also cover only slightly less than a third of the surface area of the first side 14 of the first rail support member 2. In this way the compressive force applied to the first side 14 of the first rail support member 2 is applied across a significant area thereof, which results in the loading being advantageously dispersed and the support being provided to most of the first side 14 of the first rail support member 2. Likewise, the second rail support member 3 comprises two further second posttensioning mechanisms 39 and 40 of the same construction as the second post-tensioning mechanism 20 described above, and arranged parallel thereto. Therefore, the posttensioning applied to the second rail support member 3 is also applied across its extent. All the bearing plates employed in the further first post-tensioning mechanisms 37 and 38 and in the second post-tensioning mechanisms 20, 39 and 40 are the same shape and configuration as bearing plate 8 shown in Figure 7. Therefore, the compressive force applied to the first side 14 and second side 17 of the first rail support member 2, and to the first side 29 and second side 32 of the second rail support member 3, is applied across a significant area in each case, which results in the loading being advantageously dispersed and the support being provided to most of each side of the first rail support member 2 and the second rail support member 3. As shown in Figures 3 and 5 the first rail support member 2 and the second rail support member 3 are located a pre-determined distance B-B apart, such that they can support a pair of parallel rails 13 with which they are used a track gauge distance C-C apart, as explained further below. In order to facilitate this a connecting rod 42 is mounted between the first rail support member 2 and the second rail support member 3, and it is dimensioned such that they are located the pre-determined distance B-B apart. The connecting rod 42 is a T-shaped beam with its transverse portion 43 lowermost and its vertical section 44 facing upwards. As shown in Figure 1 an upper surface 45 of the first rail support member 2 comprises a first inclined mounting area 46, and an upper surface 47 of the second rail support member 3 comprises a second inclined mounting area 48. The angle of incline of the first inclined mounting area 46 and the second inclined mounting area 48 is pre-determined to suit the required angle of inward incline of the pair or rails 13 with which the railway sleeper apparatus 1 is used. Referring to Figure 2, the transverse portion 43 of the connecting rod 42 comprises a first end portion 49 which is inclined to match the angle of incline of the first inclined mounting area 46, so it sits flush thereon. Likewise, the transverse portion 43 of the connecting rod 42 comprises a second end portion 50 which is inclined to match the angle of incline of the second inclined mounting area 48, so it sits flush thereon. The first end portion 49 of the connecting rod 42 is mounted to the first inclined mounting area 46 by four first bolts 51, which pass through apertures (not visible) in the first end portion 49 and extend into the first rail support member 2. Likewise, the second end portion 50 is mounted to the second inclined mounting area 48 by four second bolts 52, which pass through apertures (not visible) in the second end portion 50 and extend into the second rail support member 3. In use the railway sleeper apparatus 1 can form a part of a railway track 60, as described below. Loads experienced in use as trains use the railway track 60 are absorbed by the first rail support member 2 and second rail support member 3, and the first posttensioning mechanisms 4, 37 and 38 and second post-tensioning mechanisms 20, 39 and 40 provide lateral support to the first rail support member 2 and second rail support member 3 respectively. The post-tensioning applied to the first rail support member 2 and second rail support member 3 prevents them splitting or cracking over time as the loads are applied. As explained above, the railway sleeper apparatus 1 is advantageous over known railway sleepers because it uses far less concrete. In addition, it will be appreciated that all the metal components of the first post-tensioning mechanisms 4, 37 and 38 and second posttensioning mechanisms 20, 39 and 40 can be readily dismantled from the first rail support member 2 and second rail support member 3 respectively for re-cycling. The first nut 9, second nut 12, first bearing plate 8 and second bearing plate 11 can be removed from the first tensioning bar 7, and the first tensioning bar 7 removed from the first aperture 5. The equivalent procedure can be performed for the first post-tensioning mechanisms 37 and 38 and the second post-tensioning mechanisms 20, 39 and 40. The bolts 51 and 52 can be removed from the first rail support member 2 and second rail support member 3 respectively, and the connecting rod 42 released. Figures 4-6 show a railway track 60 according to the second aspect of the present invention, which comprises a base layer 61, a slab 62 located on the base layer 61 and a plurality of railway sleeper apparatus 1 as claimed in claim 1 which are located on the slab 62 at spaced intervals. The railway track 60 further comprises ballast material 63 surrounding the first rail support member 2 and the second rail support member 3 of each railway sleeper apparatus 1. The base layer 61 is like known base layers of ballast railway tracks, and is made from earth or hardcore materials in the known way. The slab 62 is made from unreinforced concrete, and is 100mm thick. Each railway sleeper apparatus 1 sits on top of the slab 62, and the rails 13 are mounted onto them in the known way. The ballast material 63 is like known ballast material 63 and comprises crushed stones and / or rocks. In use the loading applied to the rails 13 by trains passing along the railway track 60 is initially borne by the first rail support member 2 and the second rail support member 3. The first post-tensioning mechanisms 4, 37 and 38 and second post-tensioning mechanisms 20, 39 and 40 help to contain the loading applied, and to prevent any failure of the first rail support member 2 and second rail support member 3, as described above. Downward load which is not absorbed by the first rail support member 2 and the second rail support member 3 is then transferred to the slab 62. The slab 62 then transfers any load it does not absorb to the base layer 61 beneath. As the slab 62 is linear and continuous along the length of the railway track 60 it transfers this loading to the base layer 61 in a far more even fashion than traditional railway sleepers. Any lateral loading, either in line with lateral axis A-A or at any angle oblique thereto, which is not absorbed by the first rail support member 2 and the second rail support member 3 is transferred to the ballast material 63. This loading is absorbed by the ballast material 63 and distributed therethrough in the known way. The railway track 60 is a hybrid railway track construction comprising features of both ballast tracks and ballastless tracks. Firstly, unlike a ballast track the railway track 60 comprises the slab 62 on which the railway sleeper apparatus 1 are located. The slab 62 provides accurate levelling of the railway sleeper apparatus 1, and underlying support for the discrete first rail support member 2 and second rail support member 3, to prevent any bending of the railway sleeper apparatus 1 as a result of irregular loading between the first rail support member 2 and second rail support member 3 in use. In this way the slab 62 effectively performs the function of the integral body of a traditional railway sleeper, which by its nature remains level. As mentioned above, the slab 62 also distributes the loading to the base layer 61 underneath more evenly than traditional sleepers distribute the loading to the ballast underneath them, because it is a continuous layer as opposed to spaced sleepers. The kinds of discrete rail ties commonly used in ballastless tracks use a similar arrangement to the slab in order to provide linear support between them, in the form of the reinforced concrete layer to which they are fixed. However, the slab 62 does not need to be as substantial in size and strength as the reinforced concrete layer of a ballastless track, as the loading it supports is far less than that with a ballastless track, due to the loading absorbed by the post-tensioned first rail support member 2 and second rail support member 3. The slab 62 can therefore be the small size shown in the Figures. Like a ballast track the railway track 60 employs the ballast material 63 to provide lateral support and elasticity to the railway sleeper apparatus 1. This arrangement therefore employs the same beneficially low installation cost of traditional ballast track compared to ballastless track, where a heavy reinforced concrete layer is used to provide all the support. Ballast is relatively easy to procure and to install, and it provides the necessary level of lateral support in this case. However, due to the inherent strength of the first rail support member 2 and the second rail support member 3, and the fact that they present twice the lateral surface area to the ballast compared to a traditional railway sleeper, far less ballast is actually required compared to in a traditional ballast track. Namely, the first side 14 of the first rail support member 2 and the second side 32 of the second rail support member 3 are both laterally supported in a leftward direction of the Figures by the ballast material 63. Likewise, the second side 17 of the first rail support member 2 and the first side 29 of the second rail support member 3 are both laterally supported in a rightward direction of the Figures by the ballast material 63. In effect, the ballast material 63 located between the discrete first rail support member 2 and second rail support member 3 provides that additional level of lateral support. Some of the loading may be transferred from the first rail support member 2 to the second rail support member 3 through the ballast material 63 in use, and vice versa, but most of it is absorbed by the ballast material 63. So, the smaller discrete first rail support member 2 and second rail support member 3, the lighter unreinforced slab 62 and the lower quantity of ballast material 63 compared to a known ballast track, all means that the hybrid railway track 60 uses far less concrete and steel than traditional ballast and ballastless tracks. It is estimated that the railway track 60 will use about 25% of the ballast commonly required for a ballast track, and only 40% of the concrete required for a ballastless track, while still providing the same level of support performance. As described above, all the railway sleeper apparatus 1 can also be dismantled at the end of the life of the railway track 60 for recycling, which is a significant advantage over known ballast and ballastless tracks. The first aspect of the invention can be altered in various ways without departing from the scope of claim 1. For example, in alternative embodiments (not shown) the first rail support member and the second rail support member have different numbers of first posttensioning mechanisms and second post-tensioning mechanisms respectively, namely one, two, four, five or more. In other alternative embodiments (not shown) the second fixture of the first posttensioning mechanism or mechanisms is simply a flange formed at the second end of the first tensioning bar, which abuts against the second side of the first rail support member. In this version of the invention the post-tensioning is provided by only tightening a nut at the first end of the first tensioning bar. An equivalent arrangement is provided in the second post-tensioning mechanism or mechanisms. The second aspect of the invention can be altered in various ways without departing from the scope of claim 16. For example, in alternative embodiments (not shown) the first rail support member and the second rail support member are attached to the slab with a fixture mechanism. Therefore, the first aspect of the present invention provides a railway sleeper apparatus which uses less concrete and steel than ballast and ballastless tracks, and which can be easily dismantled for recycling. The second aspect of the present invention provides a railway track which utilises the railway sleeper apparatus as part of a hybrid structure which uses less concrete and ballast material overall than ballast and ballastless tracks. It can also be dismantled for recycling more readily than known tracks. Claims. 1. Railway sleeper apparatus comprising a first rail support member and a second rail support member spaced apart from said first rail support member, in which said first rail support member comprises a first post-tensioning mechanism comprising a first aperture passing through said first rail support member and a first tensioning bar removably located therein with a first end thereof fixed to said first rail support member by a first fixture and a second end thereof fixed to said first rail support member by a second fixture, and in which said first tensioning bar is held under extension between said first fixture and said second fixture. 2. Railway sleeper apparatus as claimed in claim 1 in which said first rail support member and said second rail support member are spaced apart along a lateral axis of said railway sleeper apparatus, and in which said first aperture extends in the direction of said lateral axis. 3. Railway sleeper apparatus as claimed in claim 2 in which said first fixture comprises a first anchor system abutting against a first side of said first rail support member, and in which said first anchor system is axially movably locatable relative to said first tensioning bar. 4. Railway sleeper apparatus as claimed in claim 3 in which said second fixture comprises a second anchor system abutting against a second side of said first rail support member, and in which said second anchor system is axially movably locatable relative to said first tensioning bar. 5. Railway sleeper apparatus as claimed in claim 4 in which said first tensioning bar comprises a first screw thread formed in said first end thereof and a second screw thread formed in said second end thereof, in which said first anchor system comprises a first bearing plate located on said first tensioning bar and a first nut located on said first screw thread, and in which said second anchor system comprises a second bearing plate located on said first tensioning bar and a second nut located on said second screw thread. 6. Railway sleeper apparatus as claimed in claim 2 in which said second rail support member comprises a second post-tensioning mechanism comprising a second aperture passing through said second rail support member in the direction of said lateral axis and a second tensioning bar removably located therein with a first end thereof fixed to said second rail support member by a third fixture and a second end thereof fixed to said second rail support member by a fourth fixture, and in which said second tensioning bar is held under extension between said third fixture and said fourth fixture. 7. Railway sleeper apparatus as claimed in claim 6 in which said third fixture comprises a third anchor system abutting against a first side of said second rail support member, in which said third anchor system is axially movably locatable relative to said second tensioning bar, in which said fourth fixture comprises a fourth anchor system abutting against a second side of said second rail support member, and in which said fourth anchor system is axially movably locatable relative to said second tensioning bar. 8. Railway sleeper apparatus as claimed in claim 7 in which said second tensioning bar comprises a third screw thread formed in said first end thereof and a fourth screw thread formed in said second end thereof, in which said third anchor system comprises a third bearing plate located on said second tensioning bar and a third nut located on said third screw thread, and in which said fourth anchor system comprises a fourth bearing plate located on said second tensioning bar and a fourth nut located on said fourth screw thread. 9. Railway sleeper apparatus as claimed in claim 1 in which said first rail support member and said second rail support member are located a pre-determined distance apart such that they support a pair of parallel rails with which they are used a track gauge distance apart. 10. Railway sleeper apparatus as claimed in claim 9 in which a connecting rod is mounted between said first rail support member and said second rail support member such that they are located said pre-determined distance apart. 11. Railway sleeper apparatus as claimed in claim 1 in which said first rail support member comprises one or more further first post-tensioning mechanisms of the same construction as said first post-tensioning mechanism and arranged parallel thereto. 12. Railway sleeper apparatus as claimed in claim 5 in which said first rail support member comprises one or more further first post-tensioning mechanisms of the same construction as said first post-tensioning mechanism and arranged parallel thereto. 13. Railway sleeper apparatus as claimed in claim 8 in which said second rail support member comprises one or more further second post-tensioning mechanisms of the same construction as said second post-tensioning mechanism and arranged parallel thereto. 14. Railway sleeper apparatus as claimed in claim 1 in which said first rail support member and said second rail support member are made from concrete. 15. Railway sleeper apparatus as claimed in claim 6 in which said first tensioning bar and said second tensioning bar are made from steel. 16. A railway track comprising a base layer, a slab located on the base layer and a plurality of railway sleeper apparatus as claimed in claim 1 located on the slab at spaced intervals, in which said railway track further comprises ballast material surrounding the first rail support member and the second rail support member of each railway sleeper apparatus. 17. A railway track as claimed in claim 12 in which said slab is made from unreinforced concrete. 16 1024 Amendments to the claims have been filed as follows: 18

Claims

1. A railway track comprising a base layer, a slab located on the base layer and a plurality of railway sleeper apparatus located on the slab at spaced intervals, each railway sleeper apparatus comprising a first rail support member and a second rail support member spaced apart from said first rail support member, in which said first rail support member comprises a first post-tensioning mechanism comprising a first aperture passing through said first rail support member and a first tensioning bar removably located therein with a first end thereof fixed to said first rail support member by a first fixture and a second end thereof fixed to said first rail support member by a second fixture, in which said first tensioning bar is held under extension between said first fixture and said second fixture, in which said first rail support member and said second rail support member are spaced apart along a lateral axis of said railway sleeper apparatus, in which said first aperture extends in the direction of said lateral axis, and in which a connecting rod is mounted between said first rail support member and said second rail support member to space them a pre-determined distance apart from one another, in which said railway track further comprises ballast material surrounding the first rail support member and the second rail support member of each railway sleeper apparatus and in which rails are mounted to said railway sleeper apparatuses and in which said first rail support member and said second rail support member are arranged perpendicular to said rails.

2. The railway track as claimed in claim 1 in which an upper surface of the first rail support member comprises a first inclined mounting area, an upper surface of the second rail support member comprises a second inclined mounting area, and in which said connecting rod comprises a first end portion which is inclined to match the angle of incline of the first inclined mounting area and a second end portion which is inclined to match the angle of incline of the second inclined mounting area.

3. The railway track as claimed in claim 2 in which said first end portion is bolted to said first inclined mounting area and said second end portion is bolted to said second inclined mounting area.

4. The railway track as claimed in claim 2 or 3 in which said connecting rod is a T-shaped beam having its transverse portion lowermost on the first and second mounting areas and its vertical section facing upwards.16 10245. The railway track as claimed in claim 1 in which said first fixture comprises a first anchor system abutting against a first side of said first rail support member, and in which said first anchor system is axially movably locatable relative to said first tensioning bar.

6. The railway track as claimed in claim 5 in which said second fixture comprises a second anchor system abutting against a second side of said first rail support member, and in which said second anchor system is axially movably locatable relative to said first tensioning bar.

7. The railway track as claimed in claim 6 in which said first tensioning bar comprises a first screw thread formed in said first end thereof and a second screw thread formed in said second end thereof, in which said first anchor system comprises a first bearing plate located on said first tensioning bar and a first nut located on said first screw thread, and in which said second anchor system comprises a second bearing plate located on said first tensioning bar and a second nut located on said second screw thread.

8. The railway track as claimed in claim 1 in which said second rail support member comprises a second post-tensioning mechanism comprising a second aperture passing through said second rail support member in the direction of said lateral axis and a second tensioning bar removably located therein with a first end thereof fixed to said second rail support member by a third fixture and a second end thereof fixed to said second rail support member by a fourth fixture, and in which said second tensioning bar is held under extension between said third fixture and said fourth fixture.

9. The railway track as claimed in claim 8 in which said third fixture comprises a third anchor system abutting against a first side of said second rail support member, in which said third anchor system is axially movably locatable relative to said second tensioning bar, in which said fourth fixture comprises a fourth anchor system abutting against a second side of said second rail support member, and in which said fourth anchor system is axially movably locatable relative to said second tensioning bar.

10. The railway track as claimed in claim 9 in which said second tensioning bar comprises a third screw thread formed in said first end thereof and a fourth screw thread formed in said second end thereof, in which said third anchor system comprises a third bearing plate located on said second tensioning bar and a third nut located on said third screw thread, and in which said fourth anchor system comprises a fourth bearing plate located on said second tensioning16 1024bar and a fourth nut located on said fourth screw thread.

11. The railway track as claimed in claim 1 in which said first rail support member and said second rail support member are located a pre-determined distance apart such that they support a pair of parallel rails with which they are used a track gauge distance apart.

12. The railway track as claimed in claim 1 in which said first rail support member comprises one or more further first post-tensioning mechanisms of the same construction as said first post-tensioning mechanism and arranged parallel thereto.

13. The railway track as claimed in claim 7 in which said first rail support member comprises one or more further first post-tensioning mechanisms of the same construction as said first post-tensioning mechanism and arranged parallel thereto.

14. The railway track as claimed in claim 10 in which said second rail support member comprises one or more further second post-tensioning mechanisms of the same construction as said second post-tensioning mechanism and arranged parallel thereto.

15. The railway track as claimed in claim 1 in which said first rail support member and said second rail support member are made from concrete.

16. The railway track as claimed in claim 8 in which said first tensioning bar and said second tensioning bar are made from steel.

17. A railway track as claimed in claim 1 in which said slab is made from unreinforced concrete.

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