EP2665864B1

EP2665864B1 - Method for manufacturing an embedded rail track

Info

Publication number: EP2665864B1
Application number: EP12703611.9A
Authority: EP
Inventors: Gerrit Marinus Van Der Houwen; Paulus Bonifatius Maria LANGE
Original assignee: Edilon Sedra BV
Current assignee: Edilon Sedra BV
Priority date: 2011-01-21
Filing date: 2012-01-20
Publication date: 2015-08-19
Anticipated expiration: 2032-01-20
Also published as: WO2012099473A1; EP2665864A1; NL2006044C2

Description

The present invention relates to a method for manufacturing an embedded rail track with a continuous and elastically supported rail embedded in a continuous concrete track bed. Such embedded rail systems are generally known in the field of railway tracks for e.g. train, tram, metro, crane and other railbound vehicle applications. The resilient behaviour of the elastic support for the rails, both in vertical and lateral direction, e.g. allows for reduction of noise and vibration.
In a known manufacturing method first a concrete track bed is made, e.g. using a slipform machine, with open-topped channels wherein the rails is placed. Then a pourable resilient compound is poured. This compound cures over time in the channel with the rail. This compound remains permanent elastic. The compound bonds to the rail and in cured state provides continuous vertical and horizontal elastic support to the rail.
In another approach rails which are covered on the sides of the web and underneath the foot by a rubber jacket are held in pre-aligned condition by use of portals from which they are suspended. Then the concrete track bed, or at least the top layer thereof, is poured so that the rails with rubber jackets are embedded in the track bed. The rubber material, commonly made of scrap rubber, provides permanent elastic support both in vertical and lateral direction for the rail.
EP 1 916 336 discloses a method for manufacturing an embedded rail track with a continuous and elastically supported rail embedded in a continuous concrete track bed, wherein a rail has a head, a web and a foot. In this known method a pre-aligned rail is provided with filler blocks on opposed sides of the web as well as with an elastic strip underneath the foot. The concrete track bed is poured and allowed to harden so that the pre-aligned rails is embedded in the concrete track bed.
In EP 1 916 336 the filler blocks each have a removable top portion that covers the respective lateral side of the rail head prior to pouring of the concrete. After the concrete track bed has hardened the top portions are removed and the voids created by removal of the top portions are filled with a pourable resilient compound which cures over time and has permanent elasticity.
The present invention aims to provide an improved method for manufacturing an embedded rail track with a continuous and elastically supported rail embedded in a continuous concrete track bed.
The present invention achieves this aim by providing a method according to claim 1.
In the method one or more pre-aligned rails are provided with filler blocks on opposed sides of the web as well as with an elastic strip underneath the foot, and a concrete track bed is poured and allowed to harden thereby embedding said one or more pre-aligned rails in the concrete track bed.
At the boundary between each filler block and the hardened concrete track bed a layer of the filler block is removed by machining to create a void down to the level of the elastic strip.
These voids that are created by said machining are then filled by pouring into the voids a pourable resilient compound which cures over time and has permanent elasticity.
In the method according to the invention the filler blocks can be of low cost as they need not have a permanent elastic property to obtain the desired elastic support of the rail. The presence of the filler blocks - after the machining step - allows for the use of a limited volume of rather expensive resilient compound to obtain the desired permanent elastic support for the rail, which elastic support is in lateral direction primarily determined by said compound and in vertical direction by the elastic strip underneath the foot of the rail.
In a practical embodiment the filler blocks and the elastic strip are separate parts, that are mounted onto the rail, e.g. by clamping. In an alternative embodiment the filler blocks and elastic strip are interconnected similar to a jacket or the elastic strip is integrated with one of the filler blocks.
In a practical embodiment the filler blocks have a length between 0.5 and 3 meters, e.g. 1.2 meter.
In a preferred embodiment the filler blocks are made of a plastic foam material, more preferably a rigid plastic foam material, e.g. a polyurethane rigid foam.
The method of the invention allows to achieve a good electrical insulation of the rail, as the compound preferably has an electrical insulating property and fills any joints between the filler blocks, possibly also joints between the elastic strip and the filler blocks. This is e.g. beneficial in view of electrical stray currents, e.g. when the track is used for a metro or tram.
In a preferred embodiment the resilient compound is a polyurethane based compound, e.g. including cork granules.
In a practical embodiment the machining of the filler blocks is performed by a brush, preferably a rotating steel wire disc brush. The brush will gradually remove material from the filler block, the thickness of the brush preferably being such that it corresponds to the thickness of the layer to be removed from the filler blocks. A machine having two spaced apart brushes or other machining tools may be used to remove the layers at both sides simultaneously. As an alternative a rotating disc saw may be used or a chain saw type machine or any other suitable machining tool.
In a preferred embodiment the filler blocks each have a top portion that covers the respective lateral side of the rail head prior to the pouring of the concrete, and - after the concrete track bed has hardened - the top portion of each filler block is removed. The void created by the removal of each top portion is also filled with said pourable resilient compound. Possibly the void created by removal of a top portion is filled with another compound than the void at the lateral side of the filler block.
In a preferred embodiment the top portions of the filler blocks each have a greater lateral dimension than the thickness of the layer of the filler block that is removed by machining at said boundary with the concrete. This avoids contact between the rail head and the machining tool when the top portions remain in place during said machining.
In a preferred embodiment the filler blocks each have a lower portion that covers or overlaps at least partially the lateral side of the elastic strip that is present underneath the foot, and the removal by machining of said layer of filler block includes removal of said lower portion. In this manner the void at the boundary can be made - if desired - to extend just as deep in the concrete track bed as the bottom side of the elastic strip. This e.g. enhances the electrical insulation and/or the lateral elastic support.
It is preferred that - after removal of the layers of the filler blocks at the boundary with the concrete - spacer elements, preferably elastic spacer elements, are placed between the filler blocks and the concrete track bed to maintain the position of the rail prior to pouring of the resilient compound. It is envisaged that elastic spacers remain in place and so become embedded in the compound.
To obtain a reliable adherence of the compound to the rail head and to the concrete track bed opposite said rail head - prior to pouring the resilient compound - the sides of the rail head and opposed portions of the concrete track bed are cleaned and possibly treated with a primer that enhances the bond with the compound. Due to the high quality adherence e.g. ingress of water can be avoided.
In a preferred embodiment use is made of support and alignment portals or jiggs from which the rail or rails is/are kept suspended during the pouring of the concrete track bed. This is known in the art as the top - down method.
In a possible embodiment the filler blocks have a preformed cut therein which separates the top portion to be removed from the remainder of the filler block except for a bridge near the lateral face of the filler block, such that upon removal by machining of said layer at the boundary with the track bed said bridge is fully or at least for 50% removed, thereby facilitating the removal of said top portion. This e.g. allows to predefine the size of the top portion that is to be removed, e.g. avoiding the removal of an undersized top portion.
In a possible embodiment one or preferably both of the filler blocks each have on the lateral face thereof an elongated protective strip, e.g. as described in EP1988213 . The strip is preferably a steel strip, but other materials are also possible. The strip is connected to the lateral face of the filler block, e.g. by an adhesive. The filler block does not extend over the height of the lateral face but is shorter so as to leave the bottom region of the lateral face exposed. The strip extends essentially over the length of the filler block, e.g. slightly shorter than the filler block when the strip is of metal. The strip extends in an upper corner region of the filler block, preferably so as to have a top face that is level with the adjacent top face of the track bed (e.g. with a concrete top face of the concrete track bed or with the top face of a road surface layer, e.g. of asphalt or bricks on top of the concrete track bed). Preferably the strip has anchoring members protruding sideways, e.g. horizontally or angled downwards, from the protective strip, e.g. at least 3 centimeters sideways from the strip, e.g. embodied as hooks, loops, rods (e.g. with a thickened end portion), etc, to obtain a reliable anchoring in the track bed.
In an embodiment a road surface layer is placed on top of the concrete track bed, e.g. an asphalt layer, possibly prior to the steps of removal of the layers from the filler blocks and filling the voids with pourable resilient compound.
The invention also relates to an embedded rail track with one or more continuous elastically supported rails manufactured according to the invention.
The invention will now be explained with reference to the drawings. In the drawings:

Figure 1 shows schematically in cross-section an example of a rail to be integrated in an embedded rail track manufactured according to the invention,
Figure 2 the rail with elastic strip clamped onto the foot of the rail,
Figure 3 the rail of figure 2 after mounting of preferred embodiments of the filler blocks,
Figure 4 the rail after pouring of the concrete track bed,
Figure 5 the track bed and rail of figure 4 after the step of removal by machining of the layers of the filler blocks at the boundary with the concrete track bed,
Figure 6 illustrates the removal of the top portion of each of the filler blocks,
Figure 7 illustrates the placement of spacers between the filler blocks and the concrete track bed,
Figure 8 illustrates the cleaning and coating with a primer of the lateral side of the rail head and the laterally opposed surface of the concrete,
Figure 9 shows the rail and track bed after the filling of the voids with the resilient compound.

Figure 1 shows an example of a steel rail 1 for a rail-bound vehicle, e.g. for tram, metro, train, etc. The rail 1 is destined to be integrated in an embedded rail track, e.g. with two parallel rails 1, with continuous elastically supported rails that are embedded in a continuous concrete track bed.
The rail 1 has a head 2, a web 3, and a foot 4. In this example, as seen in cross-section of the rail 1, the head 2 and the foot 4 are substantially broader than the web 3, so that on each lateral side of the rail 1 there is a longitudinal recess 6, 7.
The rail 1 shown as an example here is a so-called grooved rail having a groove 10 in the rail head 2.
The rail 1 may also have a different shape, e.g. without groove 10 and/or with other dimensions of the rail head, web, and/or foot.
In figure 2 an example of an elastic strip 15 has been mounted onto the rail 1 and extends underneath the foot 4. In this example the strip 15 has lateral flanges 15a, b that are adapted to be clamped around the lateral sides of the foot 4.
The strip is of elastic material that is suitable to provide continuous elastic support in vertical direction for the rail 1. These strips 15 are known in the art and can have a static and dynamic stiffness depending on the desired elastic properties of the rail support.
In figure 3 it is shown that filler blocks 20 and 25 are mounted to the rail 1. Here, as is preferred, the filler blocks 20, 25 are clampingly fitted in the recesses 6, 7.
In an embodiment the strip 15 could extend on the upper side of the foot on both sides of the web of the rail, a filler block then clamping the strip onto the upper face of the foot.
In an embodiment the strip 15 has no lateral clamping flanges 15a, b but is held by another clamping member onto the rail, or by an adhesive. In an embodiment an additional clamping strip is provided that has clamping flanges 15a, b, the elastic strip 15 being arranged between said additional clamping strip and the rail foot 4.
As is preferred the filler blocks 20, 25 are of rigid material, as the blocks themselves do not need to have permanent elastic properties that contribute to the elastic support for the rail 1. Preferably the filler blocks 20, 25 do not include rubber.
In a preferred embodiment that blocks 20, 25 are made of a plastic foam material, most preferably a rigid plastic foam material, such as rigid polyurethane foam.
In a possible embodiment such blocks 20, 25 are cut from thick sheets or plates of rigid plastic foam material.
Preferably the filler blocks have a very low water absorption.
Preferably the filler blocks 20, 25 have a length between 0.5 and 3 metres to facilitate handling of the blocks 20, 25 during installation.
In this example the rigid foam filler blocks 20, 25 have a preformed cut 21 therein at the side to be introduced and clamped in the recess of the rail. The cut 21 is adapted to provide some flexibility to said portion of the block 20, 25 so that the filler block will remain in place based on the clamping effect alone on the pre-aligned rail.
The lateral sides of the filler blocks 20, 25 are shown here to be planar and parallel. However other embodiments are also possible, e.g. with non-parallel and/or non-planar vertical sides, e.g. the lateral sides tapering upwards to a smaller cross-sectional dimension of the assembly and/or the lateral sides having one or more longitudinal ribs or other formations that cause an uneven surface in the concrete, e.g. to enhance the engagement of the compound with the concrete track bed.
If desired the elastic strip 15 and/or the filler blocks 20, 25 can also be held in a different, possibly temporary, manner on the rail 1, e.g. using adhesive, clips, tie-wraps, etc prior to the pouring of the concrete into which the assembly of figure 3 is to be embedded..
As can be seen in figure 3 the filler blocks 20, 25 are - as is a preferred embodiment - shaped such that they each have a top portion 20a, 25a that covers the respective lateral side of the rail head 2. As is preferred, these top portions 20a, 25a are later removed prior to the pouring of the compound.
As can be seen in figure 3 the filler blocks 20, 25 are - as is a preferred embodiment - shaped such that they each have a lower portion 20b, 25b that covers the side of the elastic strip 15. Here, as is preferred, the lower portion 20b, 25b extends down to the bottom side of the strip 15, but an embodiment with less overlap in vertical direction between the strip 15 and the lower portion 20b, 25b is also possible. Then the concrete will lock-in the elastic strip 15 in horizontal direction, which may be beneficial.
In this example, as is preferred, the filler blocks 20, 25 each have a preformed cut 27 therein which separates the top portion 20a, 25a to be removed from the remainder of the filler block except for a bridge near the outer side face of the filler block.
The assembly in the condition as shown in figure 3 is held in a pre-aligned state prior to the pouring of the concrete in which the assembly is to be embedded. As is known in the art, the top - down method can be used, wherein use is made of support and alignment portals or jigs (not shown) from which the assembly, or commonly multiple assemblies at the correct gauge between the rails, is suspended, e.g. above a concrete foundation that was installed earlier.
In an alternative approach other support and alignment members are used to hold the assembly to be embedded at the correct pre-aligned position prior to pouring of the concrete.
Figure 4 illustrates that the concrete 30 has been poured, here underneath and at each of the sides of the assembly of figure 3. In this example the concrete is poured up to the top face of the filler blocks 20, 25. If desired the top level of the concrete track bed could be lower, e.g. allowing for an additional cover layer, e.g. a non concrete road surface, to be placed on top of the concrete track bed.
The poured concrete 30 is now allowed to harden.
Figure 5 illustrates the step of removing a layer of the lateral side of the filler block by machining away said layer at the boundary between each filler block and the concrete track bed. As is shown in figure 5 in this manner a void 40, 45, preferably narrow and deep slot, is formed. The machining is performed so deep that even the lower portions 20b, 25b are removed.
In a practical embodiment the layer to be removed from each filler block 20, 25 by machining at the boundary with the concrete track bed has a thickness of between 5 and 25 millimetres, preferably between 10 and 25 millimetres, e.g. about 15 millimetres. It will be appreciated that the thickness of the layer that is removed relates to the thickness of the layer of compound that is filled into the void, and thereby to the finally obtained elastic support of the rail.
As is possible the machining is performed with a brush, preferably a rotating disc brush, e.g. a steel wire disc brush. A suitable machine has a motor driven shaft on which such a brush can be mounted. It is envisaged that an embodiment of the filler block made of rigid plastic foam can well be machined with such a brush. An advantage of the disc brush is that the side face of the concrete is also brushed and loose particles are removed. As an alternative a saw, e.g. a disc saw, or a milling machine can be used to machine away said side layers of the filler blocks. A vacuum device may be used to suck away the machined filler particles.
If desired the filler blocks 20, 25 may include one or more preformed cuts, cut-outs or internal cavities in the region of the layer to be machined away. This may e.g. reduce the volume of filler block to be removed, the energy needed for said removal, or be otherwise be beneficial for the removal by machining and/or the adherence to the compound that is poured later into the voids.
Here, as is preferred, the top portion 20a, 25a of the filler blocks each have a greater lateral dimension than the thickness of the layer of the filler block that is removed by machining at said boundary.
In the embodiment of the filler blocks 20, 25 with the top portion 20a, 25a and the associated preformed cut in the filler block, the machining step may lead to the complete or at least 50% removal of the bridge that was present in the filler block between said top portion and the remainder of the filler block. In figure 5 it is suggested that a fraction of said bridge is let intact. Now with minimal effort the remains of the filler blocks can be removed, e.g. by some pulling action, as is illustrated in figure 6.
The cut now forms a predefined surface of the void to be filled with compound near the rail head 2.
Due to the removal of the layers from the vertical outer sides of the filler blocks 20, 25 the assembly with the rail 1 now has a reduced sideways stability. In order to avoid undue sideways shifting of the rail, it is preferred to introduce at selected positions along the track spacers 50 in the voids between the filler blocks 20, 25 and the opposed face of the concrete track bed, e.g. wedge shaped spacers.
Preferably said spacers 50 are made of elastic material, e.g. from the same material as the compound to be poured into the void, and are to be embedded in the compound permanently. Their presence then does not disturb the desired elastic property of the lateral support for the rail 1.
As is preferred - prior to the pouring of the compound into the voids 40, 45 - extra measures are taken to enhance the adhesion of said compound to the lateral side of the rail head 2 and the opposed surface of the concrete track bed. This is done to counter ingress of water, most desirable if prevention of electrical stray currents is desired.
For example the lateral side of the rail head 2 and said opposed surface (indicated with arrows A) are cleaned and coated with a suitable primer. This is illustrated in figure 8.
Figure 9 shows the embedded rail system after the resilient compound 60 has been poured into the voids 40, 45. It can be seen that the void created by removal of each top portion 20a, 25b is also filled with said pourable resilient compound.
The compound may for example be a polyurethane based compound, e.g. including cork granules.
The compound cures over time and forms a layer that remains permanently elastic, and thereby provides a continuous elastic support primarily in lateral direction for the rail 1.
It is envisaged that once the manufacturing of the rail system is completed no fasteners are present between the rails and the concrete track bed as is known in the art.
If the filler blocks 20, 25b were absent far more elastic compound would have been needed, which is more expensive and less efficient than with the method according to the invention. The filler blocks 20, 25 need not be elastic themselves, and thus can be made of a rather cheap material, such as rigid plastic foam. The machining step to remove the layers from the filler blocks can be effected quite rapidly and cost-efficient.
As mentioned above a concrete foundation bed may be present prior to the rails with elastic strip and filler blocks being aligned above said concrete foundation bed. Then an upper bed portion of concrete is poured on top of the foundation bed which forms the lower bed portion so as to embed the one or more pre-aligned rails in the concrete track bed. In another approach a monolithic concrete track bed is poured in one pouring action. Possibly a road surface layer is placed on top of the concrete track bed, e.g. an asphalt layer, paving blocks, possibly prior to the step of filling the voids with the pourable compound.
In an embodiment of the method parallel pre-aligned rails are interconnected by transverse gauge rods at intervals along the length of the rails, said gauge rods preferably being sheathed by a permanent elastic sheath, e.g. a tubular sheath, prior to the pouring of the concrete track bed. The sheathed gauge rods then also become embedded in the concrete track bed. The gauge rod may extend through the filler block or through a specially designed filler block to be arranged at the location where the gauge rod is connected to the rail. When removing by machining the layer of filler block at the boundary with the concrete at the side of the gauge rod, it is possible that a portion of said layer below the gauge rod may remains in place and only the portion of the filler block above the gauge rod is removed.
It will be appreciated that the pre-aligned rail or rails may be combined with rail fixtures, e.g. a water drainage element, e.g. a drainage box fitted to a rail or a drainage element extending transverse between rails. It is envisaged that such elements are sheathed with a permanent elastic sheath or e.g. with a sheathing, e.g. of filler block material, that is subjected to the same process including layer removal at the boundary with the concrete as explained above.

Claims

Method for manufacturing an embedded rail track with a continuous and elastically supported rail embedded in a continuous concrete track bed, wherein a rail (1) has a head (2), a web (3) and a foot (4), which method comprises the steps of:
- providing one or more pre-aligned rails (1) provided with filler blocks (20,25) on opposed sides of the web as well as with an elastic strip (15) underneath the foot,

- pouring the concrete track bed (30) and allowing said concrete to harden thereby embedding said one or more pre-aligned rails (1) in the concrete track bed,
characterised in that
at the boundary between each filler block (20,25) and the hardened concrete track bed a layer of the filler block is removed by machining to create a void (40,45) to the level of the elastic strip (15),
and in that said voids (40, 45) created by said machining are filled by pouring into the voids a pourable resilient compound (60) which cures over time and has permanent elasticity.
Method according to claim 1, wherein the filler blocks (20, 25) each have a top portion (20a, 25a) that covers the respective lateral side of the rail head prior to pouring of the concrete, and wherein - after the concrete track bed has hardened - the top portion is removed (20a, 25a),
and wherein the void created by removal of each top portion (20a, 25a) is also filled with pourable resilient compound (60).
Method according to claim 2, wherein the top portions (20a, 25a) of the filler blocks each have a greater lateral dimension than the thickness of the layer of the filler block that is removed by machining at said boundary.
Method according to one or more of the preceding claims, wherein the filler blocks each have a lower portion (20b, 25b) that overlaps the lateral side of the elastic strip (15), and wherein the removal by machining of said layer of filler block includes removal of said lower portion.
Method according to one or more of the preceding claims, wherein after removal of said layers elastic spacer elements (50) are placed between the filler blocks and the concrete track bed to maintain the position of the rails prior to pouring of the resilient compound (60).
Method according to one or more of the preceding claims, wherein - prior to pouring the resilient compound - the lateral sides of the rail head (2) and opposed portions of the concrete track bed are cleaned, and preferably treated with a primer, to enhance adhesion of the resilient compound to said surfaces.
Method according to one or more of the preceding claims, wherein the step of machining of the filler blocks (40, 45) is performed by a rotating steel wire disc brush.
Method according to one or more of the preceding claims, wherein the filler blocks (20, 25) are made of a foam material, preferably a rigid foam material, preferably polyurethane rigid foam.
Method according to one or more of the preceding claims, wherein use is made of support and alignment portals from which the rails are kept suspended during the pouring of the concrete track bed.
Method according to claim 2 or 3, wherein the filler blocks (20, 25) have a preformed cut therein which separates the top portion to be removed from the remainder of the filler block except for a bridge near the outer side face of the filler block, such that upon removal by machining of said layer at the boundary with the track bed said bridge is fully or for at least 50% removed, thereby facilitating the removal of said top portion.
Method according to one or more of the preceding claims, wherein the layer that is removed from the filler block by machining at the boundary with the concrete track bed has a thickness of between 5 and 25 millimetres.
Method according to one or more of the preceding claims, wherein the head and the foot (4) of the rail (1) are broader than the web (3), and wherein the filler blocks are clamped between the head and the foot of the pre-aligned rail.
Method according to one or more of the preceding claims, wherein the elastic strip (15) has lateral flanges clamped on the sides of the foot of the rail.
Method according to one or more of the preceding claims, wherein the track bed includes a lower bed portion of concrete and an upper bed portion of concrete, said lower bed portion being poured prior to the step of providing one or more pre-aligned rails provided with filler blocks on opposed sides of the web as well as with an elastic strip underneath the foot, the upper bed portion being poured on top of the lower bed portion so as to embed the one or more pre-aligned rails in the concrete track bed.
Embedded rail track with one or more continuous elastically supported rails embedded in a continuous concrete track bed, wherein the rail (1) has a head (2), a web (3) and a foot (4), and wherein the rail (1) is provided with filler blocks (20,25) on opposed sides of the web as well as with an elastic strip (15) underneath the foot, wherein the concrete has been poured and allowed to harden thereby embedding the rail in the concrete track bed,
characterised in that
at the boundary between each filler block (20,25) and the hardened concrete track bed a void that has been filled by pouring a resilient compound (60) which cures over time and has permanent elasticity is present, which void has been created by removal of a layer of the filler block by machining to the level of the elastic strip (15) of the rail embedded in the concrete track bed.