Technical Field

The invention relates to the field of damper systems for rail tracks, in particular to a rail damper system that is smart, easy to install and durable. Railways and rails can generate a lot of noise due to oscillations and small vibrations in the rails and it is usually a requirement to provide and install rail damper systems in densely populated areas.

Background of the Invention

Typical rail damper systems comprise a clamp or the like that extends under the foot of the rail and clamps or pushes damper elements towards the web of the rail. These clamps are typically made of a flexible and durable metal and connected to damper elements made of a softer material, which is capable of absorbing noise generating oscillations and noise generating vibrations from the rail and therewith reduce noise. The clamps are in some cases screwed to the foot of the rail and also to the damper element(s). Figure 1 illustrates a damper element 100 according to the prior art. The damper element 100 is held by a metal clamp 102 and mounted next to the web 104 of the rail 106 in order to reduce noise generation when a train or streetcar is passing over the rail. The clamp 102, which is typically made of a resilient and durable metal, extends under a base 108 of the rail 106 and holds a pair of dampers 110 next to the web 104 of the rail 106 on each side of the web 104. Thereby the clamp 102 extends over the pair of dampers 110 on both sides and the dampers 110 are held in place by screws 112 and washers 114. The screws 112 are thereby anchored in the dampers 110 via some sort of anchors 116, which are schematically illustrated in figure 1. The anchors 116 typically comprise a thread or the like to hold the screws 112 so that the dampers 110 are tightened toward the clamp 102. The clamp 102 keeps the dampers 110 in place next to the web 104.

Another damper system is shown in DE 43 22 468 A1. A disadvantage with this rail damper system is that the damper system cannot be continuous since it interferes with the fastening of the rails to the sleepers. Vibration measuring tests have however shown that damper systems, which are installed continuously along the rails have the best dampening effect, typically about 2-6db or more than 2, 3 or 4db improved noise reduction. As one can see this is however not possible with the design disclosed in DE 43 22 468 A1 , since damping arrangement and the fastening clamps and screws that are used to fasten the foot of the rail to the sleepers gets in the way of the damper system. So, the damper system of DE 43 22 468 A1 cannot be installed continuously, it needs to be interrupted at least at the fastening points between the rails and sleepers. This German document aims to provide a dampening effect by using a thick layer of adhesive that absorbs vibrations, whereby the dampening elements are glued to the rail.

Typically, damper elements are fastened towards the web of the rail so that they are mounted next to the web of the rail for instance via a clamp or the like, as illustrated in figure 1 . Other ways of fastening the damper elements to the web include the use of an adhesive or alternatively to screw an arched element or clamp or the like into the foot or base of the rail so that the arched element holds the damper element in place next to the web. If adhesive is used, the adhesive is typically a very strong adhesive and the damper element is not of the type described further herein but of a very heavy type comprising metal parts or the like, so that the heavy damper element changes the characteristic frequency of the rail due to its mass.

In addition to the above it is to be noted that traditional dampers comprise typically steel or other heavy material in the actual damper elements in order to make them heavy so that they can dampen vibrations and to change the characteristic frequency in the rails by changing the mass.

Summary of the Invention

An object of the present invention is to provide a rail damper system that is effective in dampening noise from the rails, easy to handle, simple and quick to install.

The inventor of the present invention has discovered that it is possible to design a rail damper system much simpler than ever done before by using at least one clamping element, fasteners and damper elements made of a soft, vibration absorbing material and placing the damper element on one side of the web of a rail and fastening it to the web of the rail via the clamping element and the fasteners. The damper element is thus fastened and pressed towards the web via the clamping element and the fasteners so that vibrations and therewith oscillations and noise generating vibrations, in particular oscillations generated in a direction perpendicular to a plane defined by the web of the rail and oscillations in the longitudinal direction of the rail, can be absorbed efficiently and in a very simple manner. In the optimal case two damper elements are provided, one on each side of the web.

The inventor has further realized that it is of importance to provide the damper system continuously along the rail in order to achieve the best sound and noise dampening effects. In addition, the inventor has realized that the damper system according to the present invention can be clamped to the rail in case this is wanted.

The inventor has further realized that it is important to provide a continuous dampening and a continuous pressure towards the rails of an elastic structure along the length of the web of the rail for achieving an optimal dampening effect.

Such a rail damper system provides several advantages compared to the prior art, such as:

- Easy to install

- Easy to handle

- Fast mounted

- High noise-reducing effect

- Works for aftersales and installation on existing rail systems

- Works well for new rail systems

- Economic compared to the prior art solution.

In addition to the above, the invention is based on the idea that elastic damper elements are under constant pressure towards the rails along the entire length of the rails. The constant pressure is provided with the above-mentioned clamping element and bolt fastening mechanism. This reduces vibrations and dampens the noise resulting from the rails when rolling stock is passing over rails. The elastic damper elements are directly pressed towards the web of the rail and therewith reduce the vibrations and oscillations in the rails, without adding a comparably high weight for changing the natural frequency of the rail system. Changing the weight and therewith the natural frequency is typically the strategy of prior art solutions, which strategy involves a lot of material, weight and therewith cost. Since this leads to heavy and cumbersome configurations the present invention dampens noise and vibrations by evenly pressing the elastic damper element(s) towards the web of the rail along the length of the rail. This strategy is basically based on physically reducing the amount of movement that the web of the rail can do and therewith dampen noise.

In a preferred solution the elastic damper element is pressed towards the web of the rail via pressure distribution plates and optionally further pressure distribution washers.

Disclosed herein is a rail damper system a rail damper system comprising at least one elastic damper element made of a vibration absorbing material provided to be arranged onto a web of a rail, a pressure distribution plate arranged on a side of the at least one elastic damper element that is oriented away from the web of the rail, when the rail damper system is installed on the rail. The rail damper system comprises further a fastening mechanism configured to fasten the at least one elastic damper element via the pressure distribution plate to a web of a rail. The fastening mechanism comprises at least one clamping element, wherein the clamping element is designed to press the pressure distribution plate towards the elastic damper element so that the elastic damper element is pressed snug and under constant pressure evenly distributed towards the web via the at least one clamping element, wherein the pressure distribution plate and the elastic damper element are arranged continuously and without spacing in between them along the rail.

The clamping element may include a bolt, a hex bolt or an Allen key bolt or the like or a bolt and nut combination. If the rail damper system is not arranged continuous along the rail, then its effect is reduced, which was shown by sound measuring tests.

The above-described rail damper system has the advantages listed above. The rail damper system is installed continuously along the rail, which means that the elastic damper element and the pressure distribution plate(s) are pressed towards the web without interruption or spacing in between. The elastic damper element is put under constant pressure evenly distributed along its entire length so that it is pressed towards the web of the rail along the chosen section of the rail in a continuous manner. Moreover, the rail damper system may be designed so that the joints of the pressure distribution plate and the joints of the elastic damper elements do not coincide. This provides a high noise dampening effect and a stable system.

The clamping element may be a clamp, a rod and bolt combination or a clamp and screw combination. If a screw clamp or a clamp is used, additional screws that press the pressure distribution plate and the elastic damper element towards the web of the rail may be used. Therewith a constant pressure in the elastic damper element is generated, which pressure is evenly distributed along the longitudinal extension of the rail, so that it is pressed towards the web of the rail.

If a screw, a hex bolt, an Allen key bolt or a rod and nut combination is used to press a rigid and strong plate and the pressure distribution plate towards the web of the rail, the screw, bolt or nut and bolt combination are typically tightened with a torque of about 30 to 400 Nm, preferably 40 to 300 Nm and even more preferably 60 to 250 Nm.

Neighboring clamping elements may be positioned about 70cm to 140cm from one another. The spacing or interval may be chosen according to the interval between the sleepers.

In the described invention, the function of the pressure distribution plate(s) is to evenly distribute the pressure over the entire length of the web of the rail and to ensure that the elastic damper element is under constant pressure, evenly distributed towards the web of the rail. As explained previously, this physically limits the possible movement of the rail and in particular the web of the rail and therewith dampens noise.

Another advantage of the disclosed solution is that the rail damper system does not pose a safety risk, if the rails are expanding or contracting due to temperature or other reasons, since the fastening mechanism and clamping element is not interfering with the fastening of the rails to the sleepers. The rail damper system is designed to never interfere with the fastening between rails and sleepers. Even if clamp solutions for fastening the rail damper system to the rail are used, the clamps are safe since they are designed to be stopped by the sleepers and cannot come into contact with the fastening between sleeper and rail.

In addition to the above the rail damper system is designed so that there is always a space between the head of the rail and the upper edge of the rail damper system, which means the upper edge of the pressure distribution plate and the elastic damper element(s), of at least 10mm and up to 40mm. This enables rail temping s to grip the rails and therewith enabling them to lift the rails and push new gravel under the rails and/or sleepers.

In an embodiment the clamping element comprises at least one rod or bolt and a fastener and wherein the rod is designed to extend through a hole in the web of the rail and a hole in the elastic damper element and the pressure distribution plate, the pressure distribution plate being arranged in between the fastener and the at least one elastic damper element for distributing the pressure generated by the fastener and the rod onto the at least one elastic damper element so that the elastic damper element is put under constant pressure, evenly distributed, towards the web of the rail.

The fastening mechanism and the rod and fastener may be anchored in the web via a thread on the rod and in the web. Alternatively, the anchoring may be achieved by providing a head on the rod, which head is then preventing the rod from slipping through the hole in the web, while the fastener tightens the head of the rod towards the web when screwed in. This optimizes the fastening of the at least one elastic damper element to the web and increases durability for the at least one elastic damper element, since the pressure distribution plate reduces wear and tear on the at least one elastic damper element.

In addition to the above the pressure distribution plate may have a thickness of at least 3 to 35mm depending on the material used. The pressure applied onto the at least one elastic damper element towards the web optimizes the dampening effect and thus further reduces oscillations and vibrations in the rail when a train is passing over it.

The pressure distribution plate may be made of metal, plastic, or fiber reinforced material/plastic.

The pressure distribution plate has a height that is adapted to the height of the web of the rail. It may be in the range from 10mm to 150mm, preferably 30mm to 120m and more preferably 50mm to 100mm.

In an embodiment several pressure distribution plates may be installed in the at least one damper elements in order to change the mass of the at least one damper element. Thereby a sandwich construction using a material combination that follows a soft-hard-soft-hard etc. arrangement for adding mass to the elastic damper elements may be used. Thus at least two pressure distribution plates may be arranged within the at least one elastic damper element so that a sandwich construction can be provided.

The at least one elastic damper element(s) may have a thickness of about 5 mm to 70 mm, preferably 8 mm to 60 mm and more preferably about 10 mm to 50 mm. The height of the elastic damper element(s) may be from 10mm to 150mm, preferably 30mm to 120mm and more preferably 50mm-100mm. The pressure distribution plate(s), and strong plates may be adapted accordingly. In addition, the height of the elastic damper element, the pressure distribution plate and the strong plate may be adapted to the height of the web of the rail considering that temping machine needs to be able to grip the head of the rail during maintenance.

The pressure distribution plate(s) may correspond in length and number of holes to the elastic damper elements but they do not have to. The pressure distribution plate may have 1 or more holes and extend over one or several damper element(s). The pressure distribution plate(s) may have a length of about 70cm to 140cm or longer such 70cm to 300cm. The pressure distribution plate(s) ensure a distribution of the pressure from the clamping element to the elastic damper element so that the elastic damper element is under constant pressure, which is evenly distributed along its entire length. As mentioned previously, the height of the pressure distribution plate is adapted to the height of the web of the rail so that at least a temping machine can still grip the head of the rail during maintenance work.

In another embodiment at least two elastic damper elements one arranged on each side of the web are provided. Thereby the rod extends through the hole in the web and the holes in the elastic damper elements and the fasteners are arranged to be installed on either sides of the at least two elastic damper elements, which sides face away from the elastic damper elements, on the rod so that the elastic damper elements are arranged snug towards the web when the rail damper system is installed on the rail.

This further enhances the dampening effect so that the noise resulting from the oscillations and vibrations in the rail upon a passing train can be further reduced.

The elastic damper elements and the pressure distribution plates extend alongside the rail and the web of the rail, respectively, in a continuous manner without interruption due to sleeper mountings and so on. The joints of the pressure distribution plates and the joints of the elastic damper elements may be chosen so that they are arranged at different positions and therewith do not coincide.

In a further embodiment the rail system may comprise a sleeve made of a soft vibration absorbing material, whereby the sleeve is designed to extend into the hole in the web so that it prevents the rod from having direct contact with the web when the rail damper system is installed on the rail.

The sleeve further enhances the reliability of the rail damper system in that it makes sure that the rod, which is preferably made of metal, cannot come into physical contact with the web and therewith with the rail.

The rod and the fasteners may be made of a durable and corrosion resistant metal but alternatively they may also be made of a high resistant and durable plastic or fibre reinforced material. Such a plastic may for example comprise fibres or other reinforcement.

The sleeve may be integrally formed with one of the elastic damper element(s).

In construction environment it is in many cases better with less moving elements and if the sleeve is integrally formed with one of the elastic damper element(s).

In another embodiment an inner diameter of the sleeve and a diameter of the hole in the elastic damper element are designed so that the rod fits snug and well-fitting into the hole in the elastic damper element and the sleeve.

The rod may have play in the sleeve when the elastic damper element is mounted onto the web of the rail. Play means that the rod or bolt has at least a slightly smaller outer diameter than the inner diameter of the sleeve.

In a further embodiment an outer diameter of the sleeve and a diameter of the hole in the web of the rail are designed so that the sleeve fits snug and well-fitting into the hole in the web.

The tight and snug fitting of the sleeve in the hole in the web and the tight and snug fitting of the rod in the sleeve create a system that is secure and held in place even during installation/assembly. This reduces the risk for false assembly or mounting of the rail damper system since the one or more sleeve, the at least one (or more) elastic damper element, the one or more rod or bolt and the one or more pressure distribution plate are all in a predetermined relationship with one another when they are assembled.

The hole in the pressure distribution plate may be chosen so that the rod fits wellfitting, snug, and tight into it.

In case several holes are provided in the elastic damper element(s), the web and pressure distribution plate all of these holes may be chosen so that a tight and snug fitting can be performed during assembly.

The elastic damper element(s) may be tightened to the web with one fastening mechanism, thus one hole, one rod and one fastener. However, several fasteners and rods or bolts may be used for each pair of elastic damper elements.

The elastic damper element may have a length, as measured in the longitudinal direction of rail, of around 50cm to 200cm, preferably 60cm to 190cm and more preferably about 70cm to 150cm.

In the above case, thus when the elastic damper element is fastened with a fastening mechanism comprising a rod and screw or clamp to the web of the rail, the holes in the web of the rails or the fixing points for the clamps or clamp and screw combination may be spaced and chosen at an interval of 60 to 200cm, preferably 70 to 140cm, as measured in a longitudinal direction of the rail. Several fastening mechanism may be used per elastic damper element or per pair of elastic damper elements.

As mentioned above, the torque values for any screws, bolts or screw and nut combinations, which ensure the constant pressure in the elastic damper element(s) evenly distributed along the entire length of the rail, may be chosen to be in the range of about 30 to 400 Nm, preferably 40 to 300 Nm and even more preferably 60 to 250 Nm.

The distance or interval between the holes in the web of the rail or the fixing points the clamps or clamp and screw combinations, as measured in the longitudinal direction of the rail, may be adapted according to the length of the elastic damper element and/or the length of the pressure distribution plate(s) and or the distance between the sleepers.

The pressure distribution plate may extend over one elastic damper element or alternatively over a plurality of elastic damper elements or elastic damper element units.

Similarly, to the above, the elastic damper element(s) may extend along the rail, while a plurality of pressure distribution plates may not be extending in a similar manner but may be arranged in intervals covering one or several holes along one long elastic damper element.

The rod may be a threaded rod and the fasteners may comprise nuts and washers.

Alternatively, to the above the rod may be a bolt where fasteners can be attached on either end in order to fix the elastic damper element to the rail.

The washers may have a thickness of 2 to 6mm, preferably 3 to 5mm and more preferably 3 to 4mm. The outer diameter of the washers may be in the range from 20mm to 80mm.

If threaded rods, nuts and washers are used, then standard fastening tools and material may be used, which facilitates installation and repair.

The shore A hardness of the elastic damper elements may be between 5 to 100, preferably 10 to 80.

This range achieves good dampening effects.

The material of the elastic damper element may be Polyurethan, Polytene, Polyurethane foam, Cork rubber, rubber, Rockwool, or any other suitable type of material. In a further embodiment the rail damper system may comprise at least one sound shield that is designed to extend along the rail and upwards towards the head of the rail. The at least one sound shield may comprise at least one hole for receiving the rod and the sound shield being arranged in between the pressure distribution plate and the fastener or in between the pressure distribution plate and the at least one elastic damper element.

The sound shield may extend along the rail over several elastic damper element(s) and or several elastic damper element units.

The sound shield further comprise the noise reduction capability of the rail damper system in that it guides noise coming from the wheels of the train or streetcar upwards and since it prevents the noise caused by the wheels of the train or streetcar to distribute horizontally.

The sound shield may be formed so that it also covers the base of the rail. In this case there may be a lower extension shield provided that covers the base of the rail when the sound shield is mounted on the rail.

In addition to the above it may be possible to mount the sound shield without the elastic damper element and in some embodiments even without the pressure distribution plate, directly onto the web of the rail via a rod and fastener combination. The shape of the sound shield may be adapted accordingly.

The sound shield may be arranged on both sides of the rail, such that both sides of the rail are noise shielded as good and efficient as possible.

In an embodiment the clamping element is a clamp comprising a base and an arm, wherein the base is arranged to extend under a foot of the rail and the arm arranged to extend on one side of a web of the rail for pressing the pressure distribution plate and the elastic damper element towards the web. The arm of the clamp may comprise a threaded hole for receiving a hex bolt or an Allen key bolt or the like, whereby the bolt can be tightened so that it applies pressure to a rigid and strong plate, the pressure distribution plate and the elastic damper element.

This bolt (hex bolt or Allen key bolt) may be tightened with a torque of about 30 to 400 Nm, preferably 40 to 300 Nm and even more preferably 60 to 250 Nm. In such a solution the clamp may further be made of a strong material such as metal and have a thickness of about 8 to 50mm, preferably more or less 10 to 30mm.

The clamp or clamping element may have a height that is adapted to the height of the rail and a width that is adapted to the width of the foot of the rail. The height of the clamp or clamping element is typically more than half of the total height of the rail for optimal positioning of the clamp or clamping element. The height of the clamping element may be in the range of 60% to 120% of the total rail height, preferably 60% to 110% and more preferably 60% to 100%.

Alternatively, to the above the arm of the clamp may comprise one or two welded nuts and a hole instead of the threaded hole. The nuts may be welded to the arm on either side or there may only be one nut present on one side of the arm.

The advantage of a solution according to the above is that no holes need to be drilled into the web of the rail, while still achieving a very high noise cancelling effect.

In a further embodiment the rail damper system comprises several clamps, wherein the clamps are configured to be arranged in regular distance intervals along the rail so that the arms extend alternating on both sides of the rail.

This can improve the use of resources, in that less material is used and ease installation.

In an embodiment the clamp may comprise two arms configured to extend on both sides of the rail for pressing the elastic damper element towards the web via the pressure distribution plate, which is in direct contact with the respective arm of the clamp.

Such double arms or symmetric arms may each comprise a bolt that presses the rigid and strong plate and/or the pressure distribution plate(s) towards the web of the rail. The double arms or symmetric arms may however also be designed to apply pressure onto the rigid and strong plate and/or the pressure distribution plate just by their shape without the use of extra bolts, hex bolts and/or Allen key bolts. In particular when a solution is chosen such as illustrated in below figure 8, then the use of the bolts can be avoided since the pressure is generated via the screw clamp at the foot of the rail. By tightening of the screws of the clamp at the foot of the rail, the arms increase their pressure onto the pressure distribution plate and the rigid and strong plate, respectively.

In still another embodiment the clamp may comprise a threaded rod and a nut connected to the arms of the clamp, so that a clamping strength and pressure towards the rigid and strong plate and/or the pressure distribution plate for providing the constant pressure in the elastic damper element(s) can be adjusted via the threaded rod and nut and the arm of the clamp and its bolt, respectively.

When clamps are used, no matter if they are double or symmetric thus comprise an arm on either side of the web of the rail or if they asymmetric thus comprise only one arm on one side of the web of the rail, a free end of the bolt that is engaged in the arm(s) of the clamp engages snug in a recess in the rigid and strong plate in order to hold the rigid and strong plate in position during tightening and use of the rail damper system.

The recess may alternatively be embodied in the pressure distribution plate, if the rigid and strong plate is not embodied or used.

The at least one elastic damper element(s) may be made of other material, such as soft metal, wood, fibre plastic, rubber, plastic or a combination thereof. Brief Description of the Drawings

The present invention will now be described, for exemplary purposes, in more detail by way of an embodiment(s) and with reference to the enclosed drawings, in which:

Fig. 1 illustrates a cross sectional view onto a rail comprising a rail damper system according to the prior art;

Fig. 2 schematically illustrates a cross sectional view onto a rail comprising a rail damper system according to the invention,

Fig. 3 schematically illustrates a cross sectional view onto a rail comprising a rail damper system according to another embodiment of the invention;

Fig. 4 schematically illustrates a cross sectional view onto a rail comprising a rail damper system with a sound shield according to another embodiment of the invention;

Fig. 5 schematically illustrates a similar embodiment as figure 3 but with a stronger distribution element in the form of a rigid and strong plate for distributing the clamping force of the nut and rod combination;

Fig. 6 schematically illustrates rail damper system comprising a symmetric clamping element;

Fig. 7 schematically illustrates a rail damper system according to another embodiment of the invention having a base wider than the foot of the rail; and

Fig. 8 schematically illustrates a rail damper system similar to figure 7 but this time with a damper cushion.

Detailed Description

Figures 2 and 3 illustrate a cross sectional view onto a rail 2 with a rail damper system 1 according to the present invention. The rail 2 comprises a head 24 a web 20 and a foot or base 22. The web 20 comprises a hole 40 for receiving a fastening mechanism 6 of the rail damper system 1 .

The rail damper system 1 comprises two elastic damper elements 4, 4’, a sleeve 8, 8’, a pressure distribution plate 10, 10’ and a fastening mechanism 6. The fastening mechanism 6 comprises a rod 28, fasteners 30 and washers 32. The fasteners 30 are embodied as nuts and the rod 28 is embodied as a threaded rod 28. Other solutions may however be possible, such as clamping systems that use a rod without a thread. The rod 28 extends through holes 26, 40 in the pressure distribution plate 10, 10’ both elastic damper elements 4, 4’ the sleeve 8, 8’ and the web 20 of the rail 2 and the fasteners 30 are arranged on either end of the rod 28 so that they press the pressure distribution plates 10, 10’ via washers 32 towards the web 20 of the rail 2 when the fasteners are tightened. The sleeve 8, 8’ is arranged in a hole 40 of the web 20 of the rail 2 in order to make sure that the rod 28 is not coming into physical contact with the rail 2. The elastic damper elements 4, 4’ the pressure distribution plates 10, 10’ and the web 20 of the rail 2 may comprise several holes for receiving several rod and fastener combinations. At least two rods 28 are arranged with a pair of elastic damper elements 4, 4’. The distance between the two rods 28 and the according holes may be in a range of 70 to 140 cm.

The sleeve 8, 8’ and the elastic damper elements 4 are made of a material that is able to dampen oscillations. Preferably the material should be elastic such as a plastic or rubber. The plastic or rubber is thereby preferably UV-light, wind and weather resistant. The pressure distribution plate 10, 10’ the rod 28, the washers 32 and the fasteners 30 are made of a metal that is durable and can withstand wind and weather. When the elastic damper elements 4, 4’ are pressed towards the web 20 of the rail 2, then a good dampening effect is achievable when trains are passing over the rail.

In the example illustrated in figures 2 and 3 the sleeve 8, 8’ is integrally formed with one of the elastic damper elements 4, 4’. It may however be a separate element 8 that extends into the hole 40 in the web 20.

As illustrated in figure 2, the sleeve 8 may be chosen to so that an outer diameter corresponds to an inner diameter of the hole 40 in the web 20 so that the sleeve 8 fits snug and tight into the hole 40. An inner diameter of the sleeve 8 may be chosen so that it leaves room to the diameter of the rod 28 and/or bolt so that the rod 28 can easily be fitted and pushed through the sleeve 8 and the elastic damper elements 4. The holes 26 in the elastic damper elements 4 and the holes in the pressure distribution plates 10 are chosen to be of the same diameter as the one in the sleeve as illustrated in figure 2. This allows an easy fitting and assembly but makes it a bit more challenging to provide a centered arrangement during assembly. This can be solved according to the embodiment of figure 3.

In figure 3 the outer diameter of the sleeve 8’ is chosen to fit tightly and snuggly into the hole 40 in the web 20 as explained referring to figure 2, while an inner diameter is chosen so that it corresponds to the diameter of the rod 28 and provides for a tight and snug fitting of the rod 28, that leaves no play in the hole 40 in the web 20.

The holes in the elastic damper elements 4’ and the pressure distribution plates 10’ may be chosen to have the same diameter as the inner diameter of the sleeve 8’ as illustrated in figure 3. Alternatively, the holes in the elastic damper elements 4’ and the pressure distribution plates 10’ may be chosen to have a different diameter that is bit bigger (similar to figure 2) than the inner diameter of the sleeve 8’. The rail damper system T illustrated in figure 3 allows for a centered arrangement during assembly.

Figure 4 shows a similar rail damper system 1” as figure 3 but with sound shields 12, 12a, 12b. The sound shields comprise of two longitudinal elements 12a, 12b that comprise a curved upper extension 42a, 42b, whereby the curved upper extensions 42a, 42b are formed to extend upwards towards the head 24 of the rail 2 and away from the head 24. One of the sound shields 12 a comprises an upper extension 42a that is extending further away from the head 24 of the rail 2 as the other sound shield’s 12b upper extension 42b. This in order to leave space for a flange of passing train wheel.

The sound shields 12a, 12b, further comprise a lower flat part 44a, 44b, which comprise holes that correspond to holes 26, 40, in the web 20, the pressure distribution plates 10’, the elastic damper elements 4’ and the sleeve 8’. The sound shields 12a, 12b may extend along a longitudinal direction of the rail 2 over several elastic damper elements 4’.

It is further conceivable to provide only one sound shield (not shown) per rail in order to only shield in one direction perpendicular to a longitudinal direction of the rail. The sound shields may be made of metal or a durable plastic.

The sound shields 12a, 12b may also be arranged on an embodiment according to figure 2 or any combination of the embodiments shown in figure 2 and figure 3. The idea of the invention has now been shown according to figures 2 to 4. Any feature combination of the embodiments illustrated in the figures may herewith be within the scope of the invention and be seen as a possible combination of features.

Figure 5 illustrates a similar solution as figure 3 but in addition to the washers 32 a rigid and strong plate 36 is arranged outside the pressure distribution plates 10, 10’ to better distribute the clamping force of the fastening mechanism 6 comprising the rod 28 and the nut 30.

The rigid and strong plate 36 may be embodied and arranged in any of the embodiments shown in figures 1 to 8. The rigid and strong plate 36 is designed to be about 6mm to 10mm thick, preferably about 8mm thick and about 20cm to 60cm in length, as measured along the length of the rails. The rigid and strong plate 36 is designed to distribute the pressure even more even and help the pressure distribution plate 10’, 10” to fulfill its function. In addition, the rigid and strong plate 36 has a height that is adapted to the height of the web of the rail and lies in the range from 10mm to 150mm, preferably 30mm to 120m and more preferably 50mm to 100mm.

Although not shown in all figures, the rigid and strong plate 36 is designed and configured to be used in any of the embodiments illustrated herein. Figure 6 illustrates a solution for a symmetric clamping element 38’ having two arms 42, 42’ and a threaded rod and nut system 50 for adjusting the pressure in the arms 42, 42’. The threaded rod and nut system 50 is embedded in the base 4T of the clamping element 38’. In addition to the use of the threaded rod and nut system 50 the arms 42, 42’ again comprise the bolts 44, 44’ for adjusting the pressure onto the elastic damper element 4, 4’ via the rigid and strong plate 36 and the pressure distribution plate 10, 10’. The bolts 44, 44’ and the threaded rod and nut system 50 together form the fastening mechanism 6’ in this case. The rail damper system 1 illustrated in figure 6 may also comprise damper cushion 48.

As mentioned previously it is possible to provide the embodiment of figure 6 without the bolts 44, 44’. In such an embodiment the constant pressure in the elastic damper elements is generated only by the arms 42, 42’ and threaded rod and nut system 50.

Figures 7 and 8 illustrate the fastening mechanism 6” comprising a clamping element 38 having a base 41 and an arm 42. The base 41 and the arm 42 are integrally formed and the base 41 is extending under a foot 22 of the rail 2. The base 41 may comprise a folded protrusion 43 at its free end, whereby said folded protrusion 43 is designed to engage with the edge of the foot 22 of the rail 2. In the arm 42 of the clamping element 38, a threaded hole is arranged through which a bolt 44 is screwed in order to engage with the rigid and strong plate 36 and the pressure distribution plate 10”, respectively.

Figure 7 basically illustrate the same solution as figure 8 with the difference that the base 41 of the clamping element 38 comprises an additional elastic damper cushion 48 arranged between the foot 22 of the rail 2 and the base 41 when the clamping element 38 is installed on the rail 2.

This elastic damper cushion 48 can be present in any of the embodiments illustrated in the figures and described in here. The damper cushion and the elastic damper elements may be made of the same material. The base 41 of the clamping element 38” of the embodiment shown in figure 7 and 8 is designed to be wider than the foot 22 of the rail 2 so that the clamping element 38” can be easily hanged onto the rail foot 22 prior to the fastening of the fastening mechanism 6” and the bolt 44, respectively. This also means that the clamping element 38” can be moved easily along the rail for correct positioning prior to fastening. The base 41 thereby comprises at least one groove 52 on at least one side of the base 41. In the illustrations in figures 9 and 10 both parts of the clamping element 38”, namely the folded portion 43 and the arm 42 comprise a groove 52 that is configured to receive the rail foot 22. The grooves 52 are arranged at intersection folded portion 43 base 41 and base 41 arm 42. One groove 52 on one side of the base 41 may be enough to suit the purpose and that is preferably the groove 52 that is arranged between the folded portion 43 and base 41 . When the bolt 44 is not tightened towards the strong plate 36 and the pressure distribution plate 10 to generate pressure onto the elastic element 4, then the clamping element 38” is easily hanging of the foot of the rail 22. Then once the clamping element 38” is moved into place and the bolt 44 is tightened then the clamping element 38” is fixed into its form-fit position.

The clamping element 38” as disclosed in figures 7 and 8 can be arranged alternating on either side of the rail 2 in order to continuously fasten the pressure distribution plate 10 and the elastic damper element 4 to the web of the rail 2.

All fastening mechanism 6, 6’, 6” disclosed herein comprise some sort of a clamping element. The clamping element can be considered to be the rod, hole and nut combination as shown in figures 2 to 5 or the clamping element as shown in figures 6 to 8.

In general, the rod described herein may be a bolt having fasteners that can be fixed to the bolt for holding various elements together or fixed to the web of the rail. Alternatively, the bolt may have bolt heads for fixing to other elements.