FIELD OF THE INVENTION

[0001] The present invention relates to rail supports for use in rail transport systems, and is particularly applicable to monorail and to narrow gauge (NG) railway track below 900mm gauge supported on slab or longitudinal supports, and preferably to monorail and to super narrow gauge(SNG) track below 600mm gauge supported on slab or longitudinal supports.

BACKGROUND TO THE INVENTION

[0002] Rail support systems are an integral part of the overall railway track system. Rail support systems maintain the correct position of the rail to the transverse sleepers, longitudinal bearers or slab (in the case of slab track). Rail support systems also accommodate a degree of flexibility to the rails and provide dampening/attenuation of noise created by railway locomotives and rolling stock travelling on the rails.

[0003] The implementation of new railway infrastructures built in urban environments, or other places where sound levels are of concern, necessitates the need for technology to keep abreast with environmental conditions such as noise pollution, as this has become a significant issue and strict environmental guidelines are in place to reduce exposure to noise and vibration.

[0004] Railway systems make transportation convenient and affordable but generate noise and vibration which can be a problem, especially close to densely populated residential and commercial areas, hospitals, research centres, and industrial areas. [0005] Some areas have a greater degree of sensitivity to noise from railways systems than others. For example, noise from passing rolling stock adjacent a hospital can cause patients to loose sleep, thereby lengthening their recovery period and time spent in hospital. Similarly, with elderly care centres or lifestyle villages for the elderly, noise from passing rolling stock can be a significant annoyance or disturbance, particularly at night.

[0006] Other areas are less prone to noise pollution problems. For example, schools, colleges, universities and other learning establishments are typically not populated at night. A certain amount of noise from railways can be tolerated, and typically above levels that would otherwise disturb hospital patients or the elderly.

[0007] Noise levels are particularly an issue from ballast-less track systems. Ballast-less track systems are around 60-70% louder in operation than a ballasted track system. With the less elastic nature of the concrete support under the rail(s), there is a higher level of noise generation at the rail-wheel interface, as well as a higher level of "Wheel Squeal" generation.

[0008] Vibration is also an issue from ballast-less track systems. Unlike in ballasted track systems where the vibration caused by the passage of the train is dispersed through the ballast layers, the vibration in the rail(s) of ballast-less track systems is absorbed by the concrete that the rail(s) is/are attached. With no ballast to disperse into, the vibrational forces become destructive forces causing damage to the underlying concrete support structure. This damage usually manifests itself in the form of cracking of the concrete at the rail ^' s fixing points.

[0009] Furthermore, in relation to monorail or narrow gauge rail systems (particularly super narrow gauge rail systems) there is no other vibration mitigating rail housing that is specifically designed for the thin structural support that exists with either a monorail or a super narrow gauge rail support structures. Existing rail supports systems are designed to spread the loading and dynamic forces over a widened footprint which is ideal for traditional sleepers or full width slabs but incompatible with a thin beam style longitudinal support structures.

[0010] In addition, several monorail systems around the world do not utilise rails as part of their transportation system. Monorails without a rail utilize rubberised wheels from the centre of the train, along with two guiding rails to the sides. The weight of the train and its dynamic forces are applied directly from the rubberised wheels to the concrete support beam because there is no ballast to disperse the load forces. This stress loading can cause cracking to the corners of the concrete support beam as the compressive forces of the train sitting directly on a marginally elastic material such as concrete causes molecular stretching of the connective bonding of concrete in the areas adjacent to the compression.

[001 1 ] Stray electric current damage to the concrete substructure is also a known problem. One of the key issues relating to concrete failure on ballast-less track systems is that of stray current leaking from the electrical track circuit system. For example, on the Chicago Metro, Vancouver sky train and the Dubai metro there has been an increase of concrete degradation in uninsulated areas. These systems have resolved the issue with the installation of insulated housings. There are no current systems that solve this engineering issue that are

specifically designed for either Monorail or Super Narrow Gauge track systems.

[0012] With such issues in mind, it is desirable to provide a rail support system applicable to a variety of locations requiring consideration of noise levels from rail traffic travelling over the rail(s) supported by the rail support system.

SUMMARY OF THE INVENTION

[0013] An aspect of the present invention provides a monorail or super narrow gauge rail support system for supporting the rail on a solid substructure, the rail support system including: a rail support pad, a first resilient material to be positioned between an underside of the rail and the rail support pad, and a second resilient to be positioned between the rail support pad and the rigid substructure.

[0014] A further aspect of the present invention provides a method of optimising a monorail or super narrow gauge rail support system for supporting the rail on a solid substructure, including the steps of providing a rail support pad of rigid material, providing a first resilient material to be positioned between an underside of the rail and the rail support pad, and providing a second resilient to be positioned between the rail support pad and the rigid substructure, whereby the first resilient material and/or the second resilient material is/are selected for preferred vibration and/or noise attenuation characteristics relating to vibration and/or noise generated by rail traffic travelling over the rail supported by the rail support system.

[0015] Preferably the rail support pad is of a rigid material, such as cast or forged iron or steel.

[0016] According to one or more preferred forms of the present invention, the second resilient material may be supported by a solid member, such as a cast iron or steel plate which is preferably itself supported by the substructure.

[0017] Preferably, either or both of the first and second resilient materials may be selected to provide preferred vibration attenuation and wear characteristics for a predetermined location application.

[0018] It will be appreciated that the present invention advantageously mitigates potential damaging effects of vibration caused by the passage of railway rolling stock, trains and locomotives over a monorail or Super Narrow Gauge (SNG) non-ballasted track infrastructure.

[0019] One or more forms of the present invention aims to address the unique issues with monorail and Super Narrow Gauge (SNG) railway track systems, and is only applicable on these systems. It is not designed or intended for use on a conventional ballasted narrow gauge, standard gauge or broad gauge railway track system.

[0020] The first and second resilient materials protect the substructure to which the rail support system is attached in two different ways as follows:

[0020a] The rail sits on the first resilient material, which preferably includes at least one resilient pad.

[0020b] The rigid material rail support pad sits on the second resilient material, which preferably includes at least one resilient pad.

[0020c] The first and second resilient materials are selected for their vibration attenuating characteristics.

[0021] Preferably, the first resilient material includes one or more pads and/or layers of High Density Polyethylene (HOPE). Preferably the HDPE may be PE300 grade.

[0022] More preferably, the first resilient material includes one or more studded pads or layers. The first resilient pad(s) or layer(s) may be of between 2mm and 20mm thickness, more preferably between 5mm and 10mm thickness, and even more preferably around 8mm thickness. [0023] The first resilient material, which is considered particularly efficacious when provided as the one or more (preferably studded) pads or layers, partially mitigates vibration on the foot of the rail whilst remaining stiff enough to provide the required support, particularly when formed of HOPE.

[0024] It has been advantageously realised that the first resilient material (being the upper resilient material compared with the lower resilient material under the rigid support) provides vibration control (attenuation/reduction) for high frequency vibrations. The high frequency attenuation range is between 50 and 100kHz.

[0025] The second resilient material of one or more forms of the present invention assists in spreading the static and dynamic loading from the rail into the solid substructure, whilst further reducing vibration.

[0026] Preferably the second resilient material includes ultra high molecular weight polyethylene (UHMWPE). More preferably, the UHMWPE may be of PE1000 grade.

[0027] As with the first resilient material, the second resilient material may be provided as one or more pads or layers of the resilient material. The second resilient pad(s) or layer(s) may be of between 5mm and 30mm thickness, more preferably between 10mm and 20mm thickness, and even more preferably between 10mm and 15mm thickness. A particular preferred thickness is around 12mm.

[0028] The second resilient support pad(s)/layers provides vibration reduction in a low frequency range of vibration.

[0029] Depending on the rail support application, the UHMWPE resilient pads can be either: solid UHMWPE throughout; solid UHMWPE at the sides thereof and studded UHMWPE in the section of the second resilient material under the rail, or; solid UHMWPE at the sides thereof with inserts (preferably of rubber but may be a third resilient material of different density or molecular weight to that of the second resilient material), and preferably embedded in the section of the second resilient material under the rail.

[0030] As well as reducing vibration in the rail, one or more forms of the present invention reduce the action and effect of torsional (twist) motion on the rail caused by dynamic loading. It has been realized that 'grinding' of the rail vehicle wheel(s) against the rail on tighter radius rail curves is reduced. This 'grind' reduction reduces the noise from train vibration along whilst also reducing "wheel-squeal" which occurs due to wheel flange-rail dynamic contact in the tighter radius curves on track.

[0031 ] It will be appreciated that one or more embodiments of the present invention provide(s) a rail support engineered solution particularly applicable to the relatively narrow, longitudinal solid bearer substructure used for monorail and super narrow gauge railway track systems rather than that of the traditional sleeper and ballast systems.

[0032] The present invention provides for reduced width rail support compared with other systems, and can be elongate in the longitudinal direction of extent of the rail compared with traditional broad rail housing for use on sleepers. In traditional rail supports used on sleeper and ballast systems, the rail support or housing extends wider across the sleeper than it does longer inline with the rail. In the system of the present invention, when two rail support s are used side by side for super narrow gauge systems, the narrower, more elongate structure of the rail support system permits rail housings to sit side by side on a 500mm to 600mm wide support structure/solid substructure.

[0033] It will be appreciated that the present invention particularly provides an advantageous rail support solution for the thinner, longitudinal bearer supporting monorail and SNG railway track rather than the traditional sleeper and ballast arrangements.

[0034] The present invention helps to spread weight of rolling stock on the rail longitudinally along the rail and down into the underlying rail support substructure rather than laterally (across a sleeper) which keeps the static and dynamic forces controlled to the strongest part of the (concrete) supporting structure.

[0034a] With regard to stray current damage to the concrete substructure, one or more forms of the present invention housing provides an insulated solution. The rail is insulated from the underlying concrete substructure in the following ways: (i) at the rail foot directly under the rail by an insulating first resilient material, preferably one or more rail seat pads, e.g. of HDPE; (ii) use of an insulated rail clip system, including an insulated rail clip; (iii) bolts retaining the rigid rail support pad to the substructure are inserted with insulated sleeves; and (iv) the second resilient material, preferably being one or more pads or layers, preferably having extended inserts through the cover plate.

[0034b] It will be appreciated that the fastening points on the rail pad for the rail clips may be offset with respect to each other. That is, not directly opposite each other across the space where the rail foot will be or is positioned. This allows the rail clips to be applied without interference from the head of an adjacent bolt holding the rail support to the substructure.

[0034c] The extended inserts preferably each include a sleeve of UHMWPE extending out of the underside of the second resilient material (e.g. pad) and which fits into an aperture (preferably respective fastener holes) in the lower cover plate to act as an insulating sleeve. [0035] Such aforementioned insulation protects the supporting substructure e.g. concrete, from the effects of electrical leakage from, for example, electrical track circuits or axle counter sub-systems.

[0036] Particular benefits of the present invention are the significant reduction in vibration into the concrete substructure and reduction in noise levels compared with known systems. For example, noise levels have been found to be reduced by up to 60% compared with noise levels from rails supported by known rail support systems for a given location, e.g. 60% vibration reduction compared with a known un-ballasted slab track system.

[0037] Furthermore, static vertical stiffness provided by the resilient materials and rigid pad arrangement of the present invention can be greater than 20kN/mm depending on the type and thickness of resilient materials selected.

[0038] It will be appreciated that embodiments of the present invention advantageously provide for selectability of resilient materials to optimize the rail support system for performance in a required location. For example, density and/or thickness of the resilient materials can be selected to tailor performance of the rail support system, and the elongate length of the resilient materials can be optimized to help spread noise and vibration dampening characteristics along the rail.

[0039] Thus, the first and/or second resilient materials can be selected as pads or layers, such as interchangeable UHMWPE resilient pads under the rigid rail support pad (preferably of cast or forged iron or steel) to facilitate use of the rail support system to be used in a wide range of applications.

[0040] Flexible, high-elasticity, vibration and noise reduction rail housing unit system for Super Narrow Gauge and Monorail systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0041 ] One or more embodiments Figure 1 shows of the present invention will hereinafter be described with reference to the accompanying figures, in which:

[0042] Figure 1 shows a vertical sectional view of a rail supported on an assembled rail support system according to an embodiment of the present invention.

[0043] Figures 2a-2d show various components from an exploded perspective view of an embodiment of the present invention.

[0044] Figure 3 shows a plan view of various components of an embodiment of the present invention.

[0045] Figure 4 shows side and plan views of a resilient material pad with projections in the form of studs, for use in one or more embodiments of the present invention.

[0046] Figure 5 shows side and plan views of a resilient material pad with inserts of different density and/or type material providing studs, for use in one or more embodiments of the present invention.

[0047] Figure 6 shows a plan view of a rail supported on a rail support system according to an embodiment of the present invention.

[0048] Figures 7a to 7c shows an alternative embodiment of the present invention having a selectable height/angle shoulder to accommodate a rail retaining clip of preferred size/type. [0049] Figure 8 shows an exploded view an alternative embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT

[0050] As illustrated in Figure 1 , a rail support system 10 according to an embodiment of the present invention includes a first resilient material 12 between the foot 14a of a rail 14 and a rigid pad or plate 16. The resilient material 12 is provided as a pad of approximately 8mm thickness (though other thicknesses are deemed to fall with in the scope of this invention) of high density polyethylene (HDPE).

[0051 ] The rigid pad or plate 16 is of cast or forged iron or steel, and includes a channel area 18 in which the first resilient material is located. This channel has sides 18a, 18b which prevent the resilient material from lateral 'creep'.

[0052] The first resilient material can include studs, bumps or other

projections 20, preferably upwards projecting towards the foot of the rail. The number and/or position of the studs, bumps or other projections, and the type and/or density of the first resilient material can be selected to optimize noise and vibration control characteristics of the rail support system.

[0053] The studs, bumps or other projections may be integral to the first resilient material or may be inserts 22 into the first resilient material, or

combinations thereof. In the case of inserts 22, these may be of different material to that of the first resilient material, which can be used to tailor the vibration and noise dampening characteristics of the first resilient material, and preferably to control wear characteristics of the first resilient material.

[0054] The rigid pad or plate 16 is located onto the second resilient material 24. The second resilient material is preferably thicker than the first resilient material, and preferably of higher density/molecular weight. Ultra High Molecular Weight Polyethylene (UHMWPE) is preferred.

[0055] In the embodiment shown in Figure 1 , the second resilient material sits on a cast or forged cover plate 26. This is an optional item depending on the actual required installation of the rail support system.

[0056] The assembly of the rigid pad or plate 16 and second resilient material, and optional cover plate, is bolted into a supporting substructure, such as a concrete support.

[0057] The rail is retained to the rigid pad or plate by a rail fastening clip system 26 and rail insulators 28 either side of the rail foot.

[0058] Figures 2a to 2d show an exploded view of components of the rail support system 10 of an embodiment of the present invention, including the rigid pad or plate 16, a pad of the second resilient material 24, and the cover plate 26. Beside these is shown a rail insulator 28 for use with the rail clip fastening system, and a pad of the first resilient material 12 with a number of studs or insert projections 20 in a preferred pattern. Also shown is a rail bolt 30 with washers 33 and bolt insulator 32.

[0059] Figure 3 shows a plan view of the rigid pad or plate 16, a pad of the second resilient material 24, the cover plate 26 and an elongate pad of the first resilient material 12.

[0060] Figures 4 and 5 show plan and side views of respective dimpled pads of first resilient material 12 (Figure 4) and with inserts (Figure 5). Preferably the inserts are of a rubber or rubberized material, or may be of other resilient material. Most preferably the inserts are of a different material and/or density to that of the first resilient material. [0061] In Figure 6, a rail 14 is supported on a rail support system 10 of the present invention. The rail support system is bolted to a concrete substructure 34, and the first and second materials are selected to provide required noise and vibration attenuation characteristics to suit the particular installation application. For example, softer, less dense first and/or second resilient materials may be selected to attenuate vibration and noise for a given location (at the expense of wear characteristics), whereas for alternative locations where noise and vibration attenuation is less of a requirement, relatively harder, more dense resilient materials may be employed.

[0062] Figure 7 shows a base plate 16a for mounting to a substrate, such as concrete, to support a rail therein.

[0063] The base plate 16a has a central recessed section 34 extending from one side edge 34a to an opposed side edge 34b of the base plate.

[0064] The recessed section may slope at an angle β non-parallel to a bottom edge or face 36 of the base plate. This angle of slope may be used to incline a rail supported on the base plate at a desired angle. Preferably the angle β of slope is no more than 10°, preferably no more than 5°, and more preferably around 2°.

[0065] The base late may include one or more holes 36 for receiving respective fasteners to fasten the baseplate to the substrate.

[0066] The base plate shown includes opposed rail retainer receivers 38a, 38b, such as rail clip 37 receivers, to which a respective rail clip is applied when the rail rests within the recess and the respective rail clips applies a retaining force through the foot of the rail. Rail clip insulators 35 can be provided (such as shown in Figure 8). [0067] Each said rail retainer receiver 38a, 38b has a respective blind or through aperture 42a, 42b to receive a portion of a respective rail clip,

[0068] As shown in Figures 7a and 7b, Figure 7b being a side view of the base plate shown in perspective in Figure 7a, each of the rail retainer receivers 38a, 38b has angled faces 40a, 40b adjoining a shoulder surface 40c.

[0069] The angled faces shown in Figures 7 and 8 are at an angle a (e.g. of approximately 25°) from horizontal or relative to the lower edge/base plate lower face 36. The rail retainer receiver therefore has a raised shoulder surface 40c. The shoulder surface ensures the rail retaining clip has the correct deflection for a required application. The height of the shoulder surface from the base edge of the rail pad/plate/floor is preferably dependent on:

• the rail retaining clip that is used

• the amount of deflection required, and

• the profile of the rail.

[0070] Therefore, advantageously, one or more forms of the present invention can be adapted to suit a range of applications and combinations of rail retaining clip and rail profile by selecting/setting the shoulder height as required. The shoulder surface may be cast or otherwise formed with the base plate, or may be provided as one or more spacers or inserts into/onto the base plate or may, for example, be attached thereto e.g. welded in place.

[0071] Figure 7c is a side on view along the recess 34 with the base plate 16a in cross section. The floor 34c of the recess 34 is sloped (inclined downward towards one of the rail clip receivers 38a, 38b and inclined upward toward the other rail retainer receiver 38b, 38a) at an angle β. It will be appreciated that the inclined/sloped floor of the recess can help to cant the rail, such as for cornering, or may be used to level the rail if the base plate/substrate is otherwise not horizontal.

[0072] An aperture 44 through the base plate at each corner thereof is used to receive therethrough a fastener, such as a screw or spike, to fasten the base plate to the substrate (such as to wood). Alternatively, respective fasteners, such as stud bolts fixed into a concrete substrate, may project up through each respective aperture and a washer, collar and/or nut applied and tightened to fasten down the base plate to the substrate.

[0073] Cast, forged or welded strengthened 46a, 46b, 48a, 48b may be provided on the rail retainer receiver(s).

[0074] A vibration and/or noise damping/attenuating material, such as an elastomer, rubber, hybrid polymer, plastic or material may be placed as a sheet or layer, preferably multiple layers, under the base plate between the base plate and the substrate.

[0075] In addition, or alternatively, a vibration and/or noise

attenuating/damping material, preferably multiple layers and/or materials, can be placed under the rail foot between the rail foot and the recess of the base plate.

[0076] Figure 8 shows an exploded view of a rail support system according to an embodiment of the present invention.

[0077] A rail 14 (section of rail shown) has a foot 14a that rests on resilient material 18 supported on a rail support pad/plate 16 which itself is supported on second resilient material 24 on a cover plate 26.

[0078] The rail is retained to the support pad/plate 16 by a rail retainer (clip) system using rail clips 37 inserted into the respective rail retainer apertures and the clips are electrically insulated from the rail support pad/plate (which can be of metal) by insulators 35.

[0079] Insulators 32 insulate the screws 30 within the support pad fastening apertures 44.

[0080] The first resilient material 18 and the second resilient material 24 provide vibration and/or noise damping/attenuation, which helps to reduce noise nuisance from tyre/wheel to rail squeal and reduces impact/load/vibration damage from the rolling stock travelling over the rail.

[0081] In use, a portion of the rail clip 37 rests on the insulator 35. The height/position of the rail clip portion is determined by the height of the shoulder surface 40c of the rail retainer receiver. That height/position can be chosen/set to suit particular applications, such as by specifying a required height of shoulder surface for a given clip system and insulator thickness.