Process for producing under-sleeper pads for a ballasted track
Patent Information
- Application Number
- EP2023828701
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-20
- Filing Date
- 2023-12-11
- Publication Date
- 2025-10-29
AI Technical Summary
Existing methods for producing sleeper soles for railway tracks with ballast beds are complex, costly, and environmentally inefficient, with issues related to adhesion, longevity, and maintenance intervals, particularly in concrete sleeper applications.
A method involving a two-layer sleeper sole produced by extrusion, comprising an elastic decoupling layer and an adhesion-promoting layer with anchor elements, where the adhesion-promoting layer is embedded in fresh concrete to ensure stable anchoring, reducing the need for downstream processing and using recycled materials.
This approach simplifies and cost-reduces the production of sleeper soles, enhances anchoring stability, extends maintenance intervals, and reduces stress on the ballast by increasing the contact area through geometric and material properties.
Smart Images
Figure 1.1
Abstract
Description
[0001] Method for producing sleeper pads for a railway track with ballast bedding
[0002] Area of
[0003] The invention relates to a method for producing sleeper bases for the elastic underside of concrete sleepers for railway tracks with ballast bedding, the sleeper base, the soled concrete sleeper and the railway track.
[0004] Background and general description of the invention
[0005] One of the most common railway track designs is with a ballasted track, meaning the sleepers are laid in a ballast bed. When concrete sleepers are used, there is usually hard contact between the concrete sleeper and the ballast, resulting in a small contact area between the ballast and the concrete sleeper. Furthermore, there is relatively low resistance to lateral displacement and relatively high ballast stress. When a train travels along the railway track, both vertical forces and lateral forces are transferred from the rail-sleeper system via the sleepers to the ballast bed and then diverted. This permanent stress on the ballasted track can, over a period of time, cause horizontal displacement of the track geometry as well as vertical unevenness of the track. Therefore, permanent travel on a railway track with a ballasted track requires that the ballast bed be tamped regularly.For tamping, ballasted tracks are typically driven over with special tamping machines or tamping trains to re-level and dynamically stabilize the ballasted track. Tamping ballasted tracks, also known as "tamping" in technical jargon, is a time-consuming and costly process that also generates significant noise pollution.
[0006] In this context, it has been shown that it can be advantageous to pad the underside of concrete sleepers with sleeper pads, also known as undersleeper pads. A sleeper pad typically comprises an elastic layer that can provide dynamic decoupling between the concrete sleeper and the ballast bed. This can potentially increase maintenance intervals, especially the intervals between re-tamping the ballast bed.
[0007] When re-soling concrete sleepers with an elastic sleeper base, one of the challenges is the permanent connection between the elastic sleeper base and the concrete sleeper body, particularly with regard to the dynamic forces that occur when a train travels along a railway track and their dissipation into the ballast bed. A number of quite different approaches to re-soling concrete sleepers have already been proposed.
[0008] EP 2 545 219 B1 proposes providing a concrete sleeper with a plastic underlay on its underside. A random fiber layer is embedded in the underside of the concrete sleeper and bonded to a single- or multi-layer plastic sheet by gluing or welding. This process therefore involves a downstream process using virgin materials as the adhesive mat, which appears to be in need of improvement in terms of production efficiency, costs, and environmental aspects. Further disadvantages include the bond between the random fiber layer and the single- or multi-layer plastic sheet, as well as the stability of the random fiber layer and the reproducibility of the bonding parameters.
[0009] EP 2 622 138 B1 proposes providing an elastic base on the underside of the concrete sleeper and using an adhesive mat with upright filaments embedded in the concrete sleeper. The filaments are attached to a base of the adhesive mat, and the base of the adhesive mat is in turn attached to an elastic mat. The base of the adhesive mat is woven to secure the filaments. Such a textile adhesive mat appears relatively complex and unstable. Furthermore, this also involves a downstream process using virgin materials as the adhesive mat.
[0010] EP 2 625 338 B1 proposes foaming a plastic foam layer, particularly polyurethane foam, onto the underside of the railway sleeper, which appears to be complex to manufacture. In particular, entirely high-quality virgin materials are used, which appears to be in need of improvement in terms of cost and environmental aspects. EP 2 697 430 B1 proposes connecting the sleeper base to the concrete body via a connecting layer that is embedded in the concrete over part of its thickness. Here, the connecting layer is formed, in particular, by a knitted spacer fabric. Here, too, entirely high-quality virgin materials are used.
[0011] EP 2 946 036 B1 proposes flocking a sleeper base made of an elastic plastic with fibers to bond the fibers to the sleeper base on the one hand and to the concrete body on the other. This also appears to be relatively complex and costly. Furthermore, entirely high-quality new materials are used here as well.
[0012] WO 2021 / 250170 A1 describes a sleeper pad made of a recycled fiber material with textile fibers.
[0013] Most of these, sometimes very different, approaches to creating sleeper pads and attaching them to the concrete sleeper have the disadvantage that the production of the sleeper pads is complex and costly in a price-competitive environment. Furthermore, these pads may each have specific qualitative disadvantages, for example, with regard to adhesion to the concrete or durability, or they may essentially require new materials.
[0014] It is therefore an object of the invention to provide a sustainable sleeper pad that can be produced easily, quickly and cost-effectively in very large quantities and yet still meets the high quality requirements for railway tracks.
[0015] Another aspect of the task is to provide an alternative sleeper sole that ensures a stable, durable and reproducible anchoring of the sleeper sole to the concrete sleeper.
[0016] Another aspect of the task is to extend the maintenance intervals, especially the tamping intervals, of a railway track with concrete sleepers in ballast, and to avoid or at least mitigate the disadvantages of the state of the art. Another aspect of the task is to increase the contact area with the concrete, particularly through geometric measures or by appropriate layer stiffness, in order to reduce the stress on the ballast and extend the maintenance intervals.
[0017] The object of the invention is achieved by the subject matter of the independent claims. Advantageous developments of the invention are defined in the subclaims.
[0018] According to one aspect of the invention, a method for producing sleeper pads for railway sleepers, in particular concrete sleepers, is provided. The sleeper pad can be used to elastically sod the concrete sleeper on its underside relative to the installation position in order to achieve elastic dynamic decoupling between the concrete sleeper and the ballast bed.
[0019] The sleeper base is designed for the elastic underside of the concrete sleeper, which is embedded in the ballast bed. The sleeper base comprises two functional layers, namely a first layer as a dynamic decoupling layer, in the form of an elastic underside mat layer for contact with the ballast bed, whose elasticity ensures dynamic decoupling between the concrete sleeper and the ballast bed, and a second layer in the form of an upper adhesion-promoting layer, which is anchored in the concrete of the concrete sleeper. For this purpose, the adhesion-promoting layer has anchor elements on its upper side, in particular in the form of embedding projections, whose size and shape are designed to be embedded in fresh concrete.When the concrete sleeper is cast, the sleeper base is pressed into the fresh concrete with the bonding layer, so that the anchor elements are embedded in the concrete, i.e., enclosed by the concrete. After the concrete hardens, the anchor elements are firmly anchored in the concrete sleeper, so that the sleeper base as a whole is anchored flat to the underside of the concrete sleeper.
[0020] The sleeper base is manufactured entirely using a special extrusion process. A continuous two-layer sleeper base is produced by extrusion in an extrusion device. The sleeper base consists of an extruded decoupling layer strand, which, after cutting to size, acts as a decoupling layer, just like a conventional sleeper base, exhibiting the elastic properties for dynamic decoupling of the track from the ballast bed, and an extruded bonding layer strand with anchor elements for embedding in the concrete, which, after cutting to size, forms the bonding layer.Both layers can be extruded together continuously in one and the same extrusion process, in particular simultaneously from the same common profile nozzle, and are inseparably connected to one another, i.e. cannot be separated non-destructively, by the joint extrusion from the common profile nozzle, i.e. before cutting, in order to form the sleeper sole strand.
[0021] The thus formed sleeper base strip can then be cut into individual sleeper base pieces to fit the shape of the concrete sleepers, e.g., punched out, to be subsequently embedded into the concrete of the concrete sleeper with the bonding layer. The manufacturing process can be fully automated, including contouring and cutting the sleeper base pieces to length, eliminating the need for any further downstream steps as with conventional blanks. Cutting into sleeper base pieces therefore only takes place after the production of the sleeper base strip, comprising both functional layers—namely, the bonding layer strip and the bonding layer strip.
[0022] Advantageously, a continuous, pre-formed, two-layer sleeper pad strand can be produced efficiently and cost-effectively, which already possesses both of the required properties of a sleeper pad: dynamic decoupling on the one hand, and embedding in the concrete on the other. The extruded strand then only needs to be cut to size to obtain a variety of finished, matching sleeper pads in the shape of the underside of the concrete sleeper.
[0023] The extrusion of the two-layer sleeper sole strand consisting of the decoupling layer strand and the adhesion-promoting layer strand can be produced either i) from the same common material formulation, which is at least partially melted in the same common extruder strand with the same common conveyor and extruded from the same common profile die as a continuous, uniform extrudate strand, so that the decoupling layer strand and the adhesion-promoting layer strand consist of the same material formulation, or ii) by coextrusion from two different material formulations, so that the decoupling layer strand and the adhesion-promoting layer strand consist of two different material formulations. In both cases, the decoupling layer strand and the adhesion-promoting layer strand are extruded simultaneously in the same extrusion device.
[0024] In case i), the common conveyor of the common extruder strand is preferably designed as a screw extruder. The common conveyor can have one or more hot-air blowers for heating the conveyor to melt the thermoplastic components of the common material formulation for the two layers in the common conveyor. The conveyor can be heated alternatively or additionally with a resistance heater.
[0025] The common material formulation may contain one or more of the following components:
[0026] - granulated elastomer recyclate, in particular granulated rubber recyclate, in particular made of styrene-butadiene rubber,
[0027] - a polyolefin,
[0028] - cable sheath shot,
[0029] - PET fibers,
[0030] - a thermoplastic elastomer, in particular urethane-based (TPE / U),
[0031] - other thermoplastics,
[0032] - an ethylene polymer wax, and / or
[0033] - further additives, whereby the components complement each other 100%.
[0034] According to a preferred embodiment, the sleeper sole strand is extruded from a material formulation that predominantly contains granulated elastomer recyclate, in particular granulated rubber recyclate, in particular styrene-butadiene rubber. The granules are preferably bonded with a thermoplastic polymer. The granulated elastomer recyclate is in particular a styrene-butadiene rubber recyclate (SBR) from recycled old tires with a grain size between 0.01 mm and 4 mm, preferably between 0.1 mm and 1.6 mm.
[0035] Preferably, the proportion of the granulated elastomer recyclate, in particular SBR, is between 50 wt.% and 98 wt.%, in particular between 70 wt.% and 95 wt.%, of the material formulation.
[0036] The granulated elastomer recyclate, in particular the granulated rubber recyclate, in particular made of styrene-butadiene rubber, is preferably not substantially melted in the extruder. Preferably, the elastomer recyclate granules are melted in a thermoplastic matrix, in particular made of a thermoplastic polymer, e.g., a thermoplastic polyolefin, to form the extrudate, i.e., the sleeper sole strand.
[0037] In case ii), the decoupling layer strand and the adhesion-promoting layer strand are extruded from two different material formulations in two different extruder strands with two different conveyors, in particular with one and the same common profile die in a coextrusion process as a coextrudate strand. This means that the two different materials for the elastic, dynamically decoupling decoupling layer and the stiffer adhesion-promoting layer can be melted in two different conveyors, possibly at different temperatures, and are combined, in particular fused together, in the melted state in the common profile die to form a two-layer strand. For this purpose, the two different conveyors are connected to the inlet of the same common profile die with a Y-shaped coextrusion connection. This means thatThe first of the two conveyors conveys and melts the thermoplastic components of the first material formulation for the decoupling layer strand, and the second of the two conveyors conveys and melts the second material formulation for the adhesion-promoting layer strand. Subsequently, the two melted, different material formulations are pressed by the two different conveyors through the coextrusion port into the common profile die, formed in the common profile die, and combined, in particular fused, to form a two-layer coextrudate strand. These two layers are preferably calibrated together in the common profile die, so that the two firmly bonded layers of different materials can be coextruded from the common profile die as a continuous two-layer sleeper pad strand.The two different material formulations therefore both form extrudable materials which are particularly compatible with each other.
[0038] The first conveyor preferably further comprises a first hopper, a first feed zone, a first compression zone, and a first discharge zone. The second conveyor preferably comprises a second hopper, a second feed zone, a second compression zone, and a second discharge zone. However, direct dosing can also be performed volumetrically or gravimetrically.
[0039] The material temperatures in the first and / or second feed zone, the first and / or second compression zone, and / or the first and / or second discharge zone of the two conveyors can be adjusted independently of each other in order to accommodate different melting temperatures of the different material formulations.
[0040] Preferably, the first and / or second conveyors are designed as screw extruders and / or each have their own heating means, e.g. one or more hot air blowers or a resistance heater, for heating the respective conveyor in order to melt the first or second material formulation separately in the first or second conveyor.
[0041] The first material formulation for the decoupling layer strand contains in particular one or more of the following components:
[0042] - granulated elastomer recyclate, in particular granulated rubber recyclate, in particular made of styrene-butadiene rubber,
[0043] - a polyolefin,
[0044] - cable sheath shot,
[0045] - PET fibers,
[0046] - a thermoplastic elastomer, in particular urethane-based (TPE / U),
[0047] - other thermoplastics,
[0048] - an ethylene polymer wax, and / or - other additives, whereby the components complement each other 100%.
[0049] According to a preferred embodiment, the elastic, dynamically decoupling decoupling layer strand is extruded from a first material formulation that predominantly contains granulated elastomer recyclate, in particular granulated rubber recyclate, in particular styrene-butadiene rubber. The granules are preferably bonded with a thermoplastic polymer.
[0050] The granulated elastomer recyclate of the first material formulation is in particular a styrene-butadiene rubber recyclate (SBR) from recycled old tires with a grain size between 0.01 mm and 4 mm, preferably between 0.1 mm and 1.6 mm.
[0051] Preferably, the proportion of the granulated elastomer recyclate, in particular SBR, is between 50 wt.% and 98 wt.%, in particular between 70 wt.% and 95 wt.%, of the first material formulation.
[0052] The granulated elastomer recyclate, in particular the granulated rubber recyclate, in particular made of styrene-butadiene rubber, is preferably not substantially melted in the extruder. Preferably, the elastomer recyclate granules are melted in a thermoplastic matrix, in particular made of a thermoplastic polymer, e.g., a thermoplastic polyolefin, to form the extrudate, i.e., the sleeper sole strand.
[0053] The second material formulation for the adhesion-promoting layer strand, which is different from the first, may contain one or more of the following components:
[0054] - a polyolefin,
[0055] - cable sheath shot,
[0056] - PET fibers,
[0057] - a thermoplastic elastomer, in particular urethane-based (TPE / U),
[0058] - other thermoplastics,
[0059] - processing additives, and / or - other additives, whereby the components complement each other 100%.
[0060] Preferably, the second material formulation may consist predominantly of a thermoplastic polymer.
[0061] In particular, the adhesion-promoting layer produced from it is harder and / or less elastic than the decoupling layer, since the adhesion-promoting layer does not participate or only participates to a minor extent in the dynamic decoupling of the sleeper base, but essentially only serves to anchor and adhere to the concrete.
[0062] The adhesion-promoting layer strand with its anchor elements from the coextruder strand and the decoupling layer strand from the main extruder strand are coextruded in particular in the common profile die.
[0063] The extrusion device has a calibration zone, a tool outlet, and a cooling zone in the area of the common profile die. The material temperatures at the calibration zone, the tool outlet, and / or the cooling zone can be adjusted independently of one another. Preferably, the temperature difference between the calibration zone, the tool outlet, and / or the cooling zone is adjustable. In particular, the profile die can have several independently controllable temperature control circuits up to the cooling zone.
[0064] Preferably, the calibration temperature is set between 70°C and 120°C and / or the cooling zone temperature is set between 0°C and 40°C. Preferably, the temperature difference between the calibration and the cooling zone is set to greater than 30°C, in particular greater than 70°C. Preferably, a different temperature profile is set in the first conveyor than in the second conveyor.
[0065] The sleeper sole strand is preferably extruded with a width between 150 mm and 400 mm, in particular between 200 mm and 350 mm, and / or a thickness between 5 mm and 25 mm, in particular between 8 mm and 20 mm. The thickness of the decoupling layer strand is preferably between 4 mm and 20 mm, in particular between 6 mm and 15 mm, and / or the thickness of the adhesion-promoting layer strand is between 1 mm and 20 mm, in particular between 2 mm and 10 mm.
[0066] The profile nozzle therefore has an essentially flat rectangular cross-section and produces the anchor elements on one of the two flat sides during extrusion as an integral part of the adhesion-promoting layer strand, e.g. in the form of knobs, ribs or similar.
[0067] After extrusion or coextrusion of the two-layer sleeper base strand, it is cut into sleeper base pieces, which, for example, either cover the entire underside of the concrete sleeper or in two halves. This produces a sleeper base for the elastic underside of the concrete sleeper for a railway track with ballast bedding. The sleeper base comprises an elastic, dynamically decoupling layer on the underside for contact with the ballast bed and an adhesion-promoting layer on the top side for anchoring in the concrete of the concrete sleeper. The adhesion-promoting layer has anchor elements on its top side that are designed to be embedded in the fresh concrete of the concrete sleeper and anchor the sleeper base in the concrete sleeper after the concrete has hardened.
[0068] The invention also relates to the soled concrete sleeper for the railway track with ballast bedding, wherein the anchor elements of the adhesion-promoting layer are embedded and anchored in the concrete of the concrete sleeper.
[0069] The invention further relates to the railway track with ballast bedding, comprising railway rails laid on a plurality of concrete sleepers so soled in this way, wherein the elastic decoupling layers rest loosely with their underside on the ballast bedding.
[0070] In the following, the invention is explained in more detail using exemplary embodiments and with reference to the figures, wherein identical and similar elements are partly provided with the same reference numerals and the features of the various exemplary embodiments can be combined with one another.
[0071] They show:
[0072] Fig. 1 is a three-dimensional view of an extrusion device for producing the sleeper sole strand according to an embodiment of the invention,
[0073] Fig. 2 is a side view of the extrusion device of Fig. 1,
[0074] Fig. 3 is a plan view of the extrusion device of Fig. 1,
[0075] Fig. 4 is a three-dimensional view of a coextrusion device for producing the sleeper sole strand according to an embodiment of the invention,
[0076] Fig. 5 is a side view of the coextrusion device of Fig. 4,
[0077] Fig. 6 is a plan view of the coextrusion device of Fig. 4,
[0078] Fig. 7 Temperature profiles of the extrusion with the extrusion device from Fig. 1 ,
[0079] Fig. 8 Pressure curves of the extrusion with the extrusion device from Fig. 1 ,
[0080] Fig. 9 Temperature profiles of the extrusion in the main extruder strand during
[0081] Coextrusion device from Fig. 4,
[0082] Fig. 10 Temperature profiles of the extrusion in the coextruder strand in the coextrusion device from Fig. 4,
[0083] Fig. 11 Pressure curves of the extrusion in the main extruder strand and in the coextruder strand from Fig. 4,
[0084] Fig. 12 a three-dimensional representation of a section of the two-layer sleeper sole strand,
[0085] Fig. 13 a cross-section through the sleeper sole strand from Fig. 12,
[0086] Fig. 14 is a plan view of a suitably cut piece of sleeper sole,
[0087] Fig. 15 is a three-dimensional representation of the sleeper base from Fig. 14,
[0088] Fig. 16 a three-dimensional representation of a half sleeper base,
[0089] Fig. 17 is a three-dimensional representation of a section of a concrete sleeper soled with the sleeper base.
[0090] Fig. 18 a schematic cross-section through a soled concrete sleeper on a ballast bed,
[0091] Fig. 19 is a schematic cross-section through a sleeper base according to an embodiment of the present invention,
[0092] Fig. 20 is a schematic cross-section through a sleeper base according to a further embodiment of the present invention, Fig. 21 is a schematic representation of the embedding of the micro-anchors according to the embodiment of Fig. 19 in a concrete sleeper,
[0093] Fig. 22 is a schematic representation of the embedding of the micro-anchors according to the embodiment of Fig. 20 in a concrete sleeper,
[0094] Fig. 23 is an enlarged schematic representation of a micro-anchor according to the embodiment of Fig. 19,
[0095] Fig. 24 is an enlarged schematic representation of a micro-anchor according to the embodiment of Fig. 20.
[0096] Detailed description of the invention
[0097] Referring to Figs. 1-3, the extrusion device 10 comprises a single extruder strand 12 with a conveyor 14, in the present example a screw extruder 16. In the screw extruder 16, an extruder screw 18 rotates in a stationary extruder barrel 20. The extruder barrel 20 is heated by several hot air blowers 22 to melt the thermoplastic components of the material formulation to be extruded. The material formulation to be extruded is fed from a hopper 24 into a feed zone 26 in the conveyor 14. The extruder screw 18 then conveys the material formulation through a compression zone 28, in which the material formulation is melted and compressed, and further into an ejection zone 30, to which a profile nozzle 32, also referred to as a tool or mouthpiece, is flanged. The profile nozzle 32 comprises a calibration 34 and a tool outlet 36 with a cooling zone 38.The extruder screw 18 is driven by a drive motor (not shown) in a drive housing 40 on the extruder strand 12.
[0098] Using the screw extruder 16 described above, a one-piece sleeper sole strand 50 made of uniform material with integral anchor elements 98 is extruded from one and the same material formulation using the same conveyor 14 (compact extrusion), which will be explained in more detail below.
[0099] Referring to Figs. 4-6, an extrusion device 10 for coextrusion is shown. The extrusion device 10 has two separate extruder strands 12a, 12b, each with a separate conveyor 14a, 14b, in the present example, each with a separate screw extruder 16a, 16b. The two separate extruder strands 12a, 12b or conveyors 14a, 14b are connected via a Y-shaped coextrusion connection 44 to the nozzle inlet 46 of the same profile nozzle 32 in order to combine the first material formulation from the first extruder strand 12a, also referred to as the main extruder strand 12a, and the second material formulation from the second extruder strand 12b, also referred to as the coextruder strand 12b, in the profile nozzle 32 in order to produce a two-layer sleeper sole strand from two different material formulations by means of coextrusion. The two extruder strands 12a, 12b, orIn the present example, conveyors 14a, 14b are designed as screw extruders 16a, 16b, each of which is divided into an intake zone 26a, 26b, a compression zone 28a, 28b, and an output zone 30a, 30b. Both conveyors 14a, 14b are fed separately from one another with different material formulations via their own feed hoppers 24a, 24b (the second feed hopper 24b is not shown in the figures). The temperature profiles in the main conveyor 14a and the co-conveyor 14b can be adjusted independently of one another to adapt to the different material formulations. The screw extruders 16a, 16b can be designed, for example, with a single screw, a counter-rotating twin screw, or a co-rotating twin screw.
[0100] The material configuration can be a single-stage compounding of the individual components in a dry mix or a two-stage compounding of the components to form a masterbatch.
[0101] The material combinations for the material formulation with the same common conveyor 14 in compact extrusion and for the main conveyor 14a in coextrusion can be selected from the following starting materials:
[0102] • SBR + MDI in the conventional pressing process
[0103] • SBR + Polyolefin (PE)
[0104] • SBR + cable sheath shot
[0105] • SBR + PET fibers from old tire recycling (pelleting may be required)
[0106] • SBR + TPE / U (thermoplastic elastomer / polyurethane)
[0107] • SBR + other thermoplastic carriers For the compact extrusion with the extrusion device of Fig. 1-3 with a single conveyor 14 as well as for the main conveyor 14a in the coextrusion process of Fig. 4-6, ie for the decoupling layer strand 60, the following material parameters and recipes are suggested:
[0108] • SBR recyclate o Grain size - 0.01 -4mm o Grain size - 0.1 -1.6mm: preferred o 70-95% o 70-95%: conventional pressing process with MDI o 70-95%: with PE o 5-100%: with cable sheath shot o 80-95%: with PET fibers o 20-95%: with TPE / U o 20-95%: other thermoplastic carriers
[0109] • Polyolefin: 0-25%
[0110] • Cable sheath shot: 0-95%
[0111] • PET fibers: 0-25%
[0112] • TPE / U: 0-25%
[0113] • Other thermoplastics: 0-25%
[0114] In the compact extrusion with the extrusion device from Figs. 1-3, the extruded two-layer sleeper sole strand 50 is extruded with one and the same conveyor 14 consisting of the elastic decoupling layer strand 60 and the adhesion-promoting layer strand 70 as a one-piece strand from a single material formulation, ie the two layers are to be understood functionally.
[0115] In the coextrusion process, the following starting materials can advantageously be used as a second different material formulation for the co-conveyor 14b, ie for the adhesion-promoting layer strand 70:
[0116] Polyolefin • Cable jacket shot
[0117] • PET fibers
[0118] • TPE / U
[0119] • Other thermoplastics
[0120] • If necessary, processing additives
[0121] According to a first embodiment, the formulation for uniform compact extrusion can be carried out with the following recipe in a one-step process without compounder: o 88% SBR 0.8-1.6mm grain size o 10% PE-LD MVR -10cm 3 / 10min o 2% PE-LD wax
[0122] The conveyor 14 is fed from the full hopper 24. A thermal or mechanical brake is used to build up a tool pre-pressure of at least 200 bar to achieve stable strand formation and homogeneously compact the material formulation. For a thermal brake, the temperature difference in the profile nozzle 32 is adjustable and can be selected to be sufficiently large. Temperature control 35, 37 of the calibration 34, the tool outlet 36, and / or, if applicable, the cooling zone 38 can be achieved using liquid or gaseous media. Example temperature profiles are shown in Fig. 7.
[0123] Fig. 8 shows exemplary pressure curves of the compact extrusion with the single conveyor 14 of the single conveyor extrusion device 10 from Fig. 1-3.
[0124] When using the coextrusion device shown in Fig. 4-6, the elastic decoupling layer strand, the elastic layer for dynamic decoupling, i.e., the actual elastic undersleeper pad, is produced with the main conveyor 14a. The co-conveyor 14b integrates the adhesion-promoting layer 70 from a separate formulation upstream of the die inlet 46 and the parallel zone 48 of the profile die 32 at the end of the main extruder strand 12a. The formulation in the co-conveyor 14b during the production of the adhesion-promoting layer strand 70 interacts with at least one formulation component of the main extruder strand 12a to ensure good adhesion of the two layers 60, 70.
[0125] The recipe for the main extruder strand 12a for producing the decoupling layer strand can be selected as follows (without compounder): o 88% SBR 0.8-1.6mm grain size o 10% PE-LD MVR -10cm 3 / 10min o 2% PE-LD wax
[0126] The main conveyor 14a is fed from the full hopper 24a. A thermal or mechanical brake is used to build up a tool pre-pressure of at least 200 bar to achieve stable strand formation and homogeneously compact the first material formulation. For a thermal brake, the temperature difference in the profile nozzle 32 is adjustable and can be selected to be sufficiently large. Temperature control 35, 37 of the calibration 34, the tool outlet 36, and / or, if applicable, the cooling zone 38 can be achieved using liquid or gaseous media. Example temperature profiles are shown in Fig. 9.
[0127] Preferably, the granulated elastomer recyclate, in the present example SBR granules, is essentially not melted itself in the extruder strand 12 of the single-conveyor extrusion device 10 from Figs. 1-3 or in the first extruder strand 12a of the coextrusion device from Figs. 4-6. Preferably, the thermoplastic components of the material formulation for the decoupling layer, in the present example containing PE-LD MVR as an example of a thermoplastic polymer, are melted during extrusion, and the SBR granules are melted into a thermoplastic matrix composed of the thermoplastic components of the material formulation to form the extrudate, i.e., the sleeper sole strand 50 or the decoupling layer strand 60. In other words, the sleeper sole strand 50 or decoupling layer strand 60 produced in this way consists predominantly of recycled elastomer (SBR) granulate embedded in a thermoplastic matrix.
[0128] The contact area with the ballast bed correlates with the stiffness of the decoupling layer 62, with the material combinations mentioned here as examples having a suitably low stiffness for the decoupling layer 62. This can reduce the stress on the ballast and thus advantageously extend maintenance intervals.
[0129] For example, the parameters for the coextruder strand 12b are selected as follows:
[0130] The second material formulation for extrusion of the adhesion promoter layer strand can be, for example, 100% PE-LD MVR -10cm 3 / 10min, which is fed from the full hopper into the co-conveyor 14b.
[0131] Fig. 9 shows exemplary temperature profiles in the main extruder strand 12a, and Fig. 10 shows exemplary temperature profiles in the coextruder strand 12b. Exemplary pressure profiles in both extruder strands 12a, 12b are shown in Fig. 11.
[0132] Referring to Figs. 12 and 13, a section of an exemplary sleeper sole strand 50 is shown, consisting of an underside elastic decoupling layer strand 60 and an upper side adhesion-promoting layer strand 70. In the illustration in Fig. 13, the decoupling layer strand 60 and the adhesion-promoting layer strand 70 are shown in different contrasts, but this should not exclude the possibility that both layer strands 60, 70 are produced uniformly from one and the same material formulation as a one-piece sleeper sole strand 50 using the compact extrusion process according to Figs. 1-3. Alternatively, the sleeper sole strand 50 from Figs. 12 and 13 can also be produced from two different material formulations using the coextrusion process according to Figs. 4-6, iewith a first elastic material formulation for the elastic decoupling layer strand 60 and a second different, in particular harder and / or stiffer material formulation for the adhesion-promoting layer strand 70.
[0133] The adhesion-promoting layer strand 70 has an adhesive structure 97 on its upper side consisting of protruding anchor elements 98, in the present example in the form of longitudinal ribs with an undercut. In this example, the longitudinal ribs have a trapezoidal cross-section.
[0134] Referring to Fig. 14-17, the sleeper sole strand 50 produced in this way is then cut out into suitable sleeper sole pieces 52, for example as a complete sleeper sole 52 as a single piece for application to the concrete sleeper 80. Alternatively, as shown in Fig. 16, mirror-side halves of the sleeper sole 52 with approximately half the sleeper length can also be cut out for application to the concrete sleeper 80. Fig. 17 shows a section of an exemplary concrete sleeper 80 soled with the sleeper sole 52. The separated remaining pieces from the pre-cut shape can be fed back into the extrusion if necessary.
[0135] Referring to Fig. 18, the sleeper base 52, consisting of the bonding layer 72 and the elastic, dynamically decoupling decoupling layer 62, is firmly connected to the underside 80b of the concrete sleeper 80. More precisely, the bonding layer 72 is firmly connected with its upper side 72a to the underside 80b of the concrete sleeper 80 by embedding the anchor elements 98 in the concrete. The elastic, dynamically decoupling decoupling layer 62 rests with its underside 62b on the ballast bed 82 and forms the elastic layer for dynamically decoupling the concrete sleeper 80 from the ballast bedding 82, whereas the stiffer or harder bonding layer 72 essentially serves only to anchor the concrete sleeper 80 in the concrete.
[0136] Figs. 19-24 show further examples of two-layer sleeper pads 52.
[0137] The harder or stiffer adhesion-promoting layer 72 can consist of a lower carrier layer 92 in the form of a plastic film 94 and an upper anchor layer 96 formed by anchor elements 98 protruding from the carrier layer 92. In this example, the anchor elements 98 take the form of single-armed plastic hooks 102 protruding upright from the plastic film 94. In the coextrusion process, the carrier layer 92 is fused with the decoupling layer strand 60 made from the other material formulation from the main extruder strand 12a. The anchor elements 98 protruding upright from the carrier layer 92 collectively form the anchor layer 96.
[0138] The adhesion-promoting layer strand 70 can be co-extruded in the co-extruder strand 12b from a thermoplastic polymer, e.g. from a thermoplastic polyolefin, e.g. polypropylene or polyethylene, with the decoupling layer strand 60 from the other more elastic material formulation, e.g. comprising predominantly SBR, in the main extruder strand 12a, wherein the co-extrusion continuously fuses both layer strands 60, 70 in the common profile nozzle 32 to form the two-layer sleeper sole strand 50.
[0139] The sleeper sole 52 subsequently cut from the sleeper sole strand 50 is accordingly formed by a layer composite of the elastic decoupling layer 62 and the adhesion-promoting layer 72 jointly formed and fused therewith on the upper side during coextrusion in the common profile nozzle 32 and can be placed as a layer composite on the freshly poured and still liquid concrete of the concrete sleeper 80 and the anchor elements 98 can be pressed into the liquid concrete.
[0140] The anchor elements 98 of the adhesion-promoting layer 72 are embedded in the fresh concrete immediately during the pouring of the concrete sleeper 80, before the concrete of the concrete sleeper 80 has hardened. The connection to the concrete on the underside 80b of the concrete sleeper 80 is created by the anchor elements 98 penetrating and thus being embedded in the fresh concrete. After the concrete has hardened, this results in a positive and non-positive connection between the anchor elements 98 in an embedding layer 81 on the underside of the thus hardened concrete sleeper 80. Due to its design as a water-impermeable plastic film 94, the carrier layer 92 forms an essentially water-impermeable barrier layer when the anchor elements 98 are embedded in the fresh concrete and a stop when the anchor elements 98 penetrate the fresh concrete.The anchor elements 98 are embedded in the fresh concrete to a defined embedding depth t, where the embedding depth t corresponds to the height h of the anchor elements 98. The height h of the anchor elements 98 can be precisely determined. In particular, the height h of the anchor elements 98 is constant across the upper surface 92a of the carrier layer 92. The carrier layer 92 is, in particular, considerably thinner than the elastic, dynamically decoupling decoupling layer 62.
[0141] The anchor elements 98 of the adhesion-promoting layer 72 can be at least partially uniform and / or have the same height h and / or the same projection b. Preferably, at least some of the anchor elements 98 of the adhesion-promoting layer 72 are identical with respect to at least one, several or all of the following properties: height h, thickness d, projection b, length of the transverse arm sections 174. Furthermore, the anchor elements 98 of the adhesion-promoting layer 72 are preferably arranged regularly over the upper side of the adhesion-promoting layer 72. In particular, the anchor elements 98 of the adhesion-promoting layer 72 are therefore not chaotically, irregularly or randomly shaped and distributed, as in a statistically rather random arrangement, e.g. in a random fiber layer or flocking.
[0142] If, upon complete embedding, the upper side 92a of the support layer 92 is in flush contact with the concrete, a predetermined uniform penetration depth t of the anchor elements 98 in the concrete can be ensured, which corresponds to the process-technically defined and preferably uniform height h of at least some of the anchor elements 98. This can ensure, among other things, a reproducible pull-off strength of the sleeper base 52 from the concrete sleeper 80 with a low statistical tolerance.
[0143] 19, 21, 23, the anchor elements 98 of the adhesion-promoting layer can be shaped, for example, as hook elements 164, which have a stem section 172 protruding from the carrier layer 92 or projecting essentially vertically, and a self-supporting arm section 174 extending transversely away from the stem section 172. The transverse self-supporting arm section 174 is formed integrally with the stem section 172. For example, the stem section 172 can protrude upright from the upper side 92a of the carrier layer 92, can then merge integrally into a curved arc section 176, which in turn merges integrally into the transverse arm section 174. Thus, the hook elements 164 can be shaped as curved, e.g., single-armed hooks. The single-armed hook elements 164 can be shaped essentially L-shaped.
[0144] An adhesion-promoting layer comprising a carrier layer 92 and anchor elements 98, e.g. hook elements 164, can also be formed in an additional co-process from an extruded carrier strip with a running injection-molded hook structure.
[0145] The angle of curvature a from the trunk section 172 to a distal end 178 of the transverse arm section 174 can be at least a = 45°, preferably at least a = 90°, or, as shown in the exemplary embodiment, even a greater than 90°. At an angle of curvature a of greater than 90°, the self-supporting arm sections 174 curve downward toward their distal ends 178, thus toward the support layer 92, whereby a particularly good anchoring of the anchor elements 98 embedded in the concrete can be achieved.
[0146] The height h of the hook element 164 in the present example is h = 0.88 mm. The thickness d of the hook element 164, in particular in the lower region of the trunk section 172 near the top side 92a of the carrier layer 92, can in this example be approximately d = 0.2 mm and the width in the direction of the transverse arm section 174, i.e. the transverse projection of the hook element 164, can be approximately b = 1 mm. The transverse arm section 174 can be tapered towards its distal end 178. The shape of the hook elements 164 can permit a sufficient embedding depth t, which is essentially equal to the height h of the hook elements 164, in the present example as approximately t = 0.88 mm, into the concrete underside 80b made of fresh concrete, which faces upwards during the manufacturing process of the concrete sleeper 80.
[0147] There is a certain scope for variation with regard to the size and shape of the anchor elements 98, although at least a portion of the anchor elements 98 of an adhesion-promoting layer 72 are uniform and / or of the same size, in particular with the same height h and / or the same projection b. Preferably, at least a portion of the anchor elements 98 of the adhesion-promoting layer 72 are identical and uniformly formed and not randomly chaotic.
[0148] In the state embedded or firmly anchored in the hardened concrete, the transverse cantilevered arm sections 174 of the anchor elements 98 extend embedded in the concrete transversely to the normal of the underside 80b of the concrete sleeper 80 and thus transversely to the withdrawal direction a and thus, in addition to the at least force-fitting connection between the concrete and the plastic surface of the anchor elements 98, also bring about a form-fitting connection or anchoring in the hardened concrete.
[0149] The thickness d and the strength of the plastic material of the anchor elements 98 are selected such that the transverse cantilevered arm section 174 can withstand a relatively large bending moment. Preferably, after the concrete has hardened, a sufficient pull-off strength, e.g., of at least 0.5 N / mm 2 or more can be achieved.
[0150] Referring to Figs. 20, 22, 24, the anchor elements 98 can also be designed as two-armed hook elements 164. They can have two opposing outwardly extending arm sections 174 that extend transversely outwardly from the trunk section 172 in a one-piece cantilever configuration. The two cantilevered transverse arm sections 174, together with the trunk section 172, can form a generally T-shaped hook element 164.
[0151] The two transverse arm sections 174 can each be integrally connected to the trunk section 172 by means of arched sections 176, so that the trunk section 172 splits into two halves in a crown 180, which then curve transversely outward into two opposite arched sections 176. The angle of curvature from the trunk section to the distal ends 178 of the arm sections 174 can also be at least 45°, at least 90°, or more. At an angle of curvature greater than 90°, the arm sections 174 curve toward the distal ends, thus back toward the support layer 92, which ensures particularly good anchoring in the concrete. Here, too, the two self-supporting arm sections 174 terminate in tapered distal free ends 178 that point obliquely downward.
[0152] The T-shaped hook elements 164 can be somewhat larger and stronger than those in single-arm hook elements. The T-shaped hook elements 164 can have a thickness d = 1 mm in the lower region of the stem section 172. The height h of the T-shaped hook elements 164, which determines the uniform embedding depth t, is approximately h = 2.5 mm in this example. The transverse projection of the two transverse arm sections 174, i.e., the transverse projection b of the T-beam, is approximately 2 mm in this embodiment.
[0153] Figures 19-24 show the upright orientation of the anchor elements 98 relative to the upper side 92a of the carrier layer 92. It can be seen that when the anchor layer 96 or the anchor elements 98 protruding from the carrier layer 92 are pressed in or embedded, these point downwards in the opposite orientation in order to be pressed into the liquid concrete. The film thickness of the carrier layer film 92 can, for example, be in the range from 0.05 mm to 0.5 mm and the anchor height h can, for example, be in the range from approximately 0.5 mm to 5 mm. Such an adhesion-promoting layer 72, for example made of polyethylene or polypropylene, can still be relatively flexible, so that the two-layer sleeper base 52 in the form of the co-extruded layer composite of the adhesion-promoting layer 72 and the elastic decoupling layer 62 is also still relatively flexible and can thus be rolled onto the fresh concrete.This allows for uniform embedding while avoiding excessive air bubbles beneath the support layer 92. After the concrete has hardened, the anchor elements 98 are finally firmly anchored in the hardened concrete through frictional or material bonding and positive locking. The transversely extending, self-supporting, yet relatively rigid arm sections 174 and / or arch sections 176 of the anchor elements 98 create a stable, positive locking of each individual anchor element 98 in the concrete. The anchor elements 98 have undersides 182 on the arm sections 174 and the arch sections 176 that extend transversely to the stem sections 172 and positively counteract a withdrawal force in the withdrawal direction a. In other words, the adhesion-promoting layer 72 forms a layer of identical anchor elements 98, which are positively anchored in the embedding layer 81 on the underside 80b of the hardened concrete sleeper 80.
[0154] The anchor elements 98 initially extend upright out of the carrier layer 92 and then merge integrally into anchoring sections extending transversely to the trunk sections 172, formed by the arch sections 176 and the transverse arm sections 174, whereby a stable, positive anchoring in the concrete can be achieved.
[0155] It may initially seem counterintuitive to extrude a sleeper base 52 by coextrusion, but it has surprisingly been shown that, on the one hand, this achieves a sufficiently strong connection between the anchor elements 98 and the elastic decoupling layer 62, and, on the other hand, the anchor elements 98 produced in this way can achieve a stable and reproducible anchoring in the concrete of the concrete sleeper 80. The inherent stability of the anchor elements 98 can also be sufficiently high. It is obvious to those skilled in the art that the embodiments described above are to be understood as examples and that the invention is not limited to them, but can be varied in many ways without departing from the scope of the claims.Furthermore, it is clear that the features, whether disclosed in the description, the claims, the figures or otherwise, also individually define essential components of the invention, even if they are described together with other features.
Claims
1. A method for producing sleeper soles (52) for the elastic underside of concrete sleepers (80) for railway tracks with ballast bedding, wherein the sleeper sole (52) comprises an elastic decoupling layer (62) on the underside for resting on the ballast bed and an adhesion-promoting layer (72) on the top side for anchoring in the concrete sleeper (80), wherein the adhesion-promoting layer (72) has anchor elements (98) on its upper side which are designed to be embedded in the fresh concrete of the concrete sleeper (80) and anchor the sleeper sole (52) in the concrete sleeper (80) after the concrete has hardened, wherein a continuous sleeper sole strand (50) is produced by extrusion in an extrusion device (10), wherein an elastic decoupling layer strand (60) and an adhesion-promoting layer strand (70) are continuously produced together in an extrusion process,are extruded from the same common profile nozzle (32) and are inseparably connected to one another by the joint extrusion from the common profile nozzle (32), and wherein the sleeper sole strand (50) thus produced is subsequently cut into individual pieces of sleeper soles (52) to match the shape of the concrete sleepers (80).
2. A method for producing sleeper soles (52) according to claim 1, wherein the decoupling layer strand (60) and the adhesion-promoting layer strand (70) are at least partially melted from the same common material formulation by means of the same common conveyor (14) and are extruded from the common profile nozzle (32) as a continuous, uniform extrudate strand.
3. A method for producing sleeper soles (52) according to claim 1 or 2, wherein the common conveyor (14) is designed as a screw extruder (16) and / or comprises one or more hot air blowers (22) or a resistance heater for heating the conveyor (14) in order to convey the common material recipe in the joint sponsor (14) at least partially.
4. A method for producing sleeper soles (52) according to claim 2 or 3, wherein the common material formulation contains one or more of the following components: - granulated elastomer recyclate, in particular granulated rubber recyclate, in particular made of styrene-butadiene rubber, - a polyolefin, - cable sheath shot, - PET fibers, - a thermoplastic elastomer, in particular urethane-based (TPE / U), - other thermoplastics, - an ethylene polymer wax, and / or - further additives.
5. A method for producing sleeper soles (52) according to claim 4, wherein the grain size of the granulated elastomer recyclate is between 0.01 mm to 4 mm, between 0.1 mm to 1.6 mm 6. A method for producing sleeper soles (52) according to claim 4 or 5, wherein the proportion of the granulated elastomer recyclate is between 50 wt.% and 98 wt%, in particular between 70 wt% and 95 wt%.
7. A method for producing sleeper soles (52) according to any one of claims 4-6, wherein the elastomer recycled granules are melted into a thermoplastic matrix.
8. A method for producing sleeper soles (52) according to claim 1, wherein the decoupling layer strand (60) and the adhesion-promoting layer strand (70) are extruded from different material formulations by means of two different conveyors (14a, 14b) in a coextrusion process as a coextrudate strand.
9. A method for producing sleeper soles (52) according to claim 8, wherein the two different conveyors (14a, 14b) are connected to the same common profile die (32) by a coextrusion connection (44), the first of the two conveyors (14a) conveying and at least partially melting the first material formulation for the decoupling layer strand (60) and the second of the two conveyors (14b) conveying and at least partially melting the second material formulation for the adhesion-promoting layer strand (70), and the two at least partially melted different material formulations are pressed by the two different conveyors (14a, 14b) through the coextrusion connection (44) into the common profile die (32), shaped in the common profile die (32) and joined together, in particular fused, to form a two-layer coextrudate strand, and extruded from the common profile die (32) as a continuous two-layer sleeper sole strand (50).
10. A method for producing sleeper pads (52) according to claim 9, wherein the first conveyor (14a) has a first feed zone (26a), a first compression zone (28a), and a first discharge zone (30a) and / or wherein the second conveyor (14b) has a second feed zone (26b), a second compression zone (28b), and a second discharge zone (30b) and wherein the material temperatures in the first and / or second feed zone (26a, 26b), the first and / or second compression zone (28a, 28b), and / or the first and / or second discharge zone (30a, 30b) are adjustable independently of one another.
11. A method for producing sleeper soles (52) according to claim 9 or 10, wherein the first and / or second conveyor (14a, 14b) are designed as screw extruders (16a, 16b) and / or each comprise one or more hot air blowers (22) or a resistance heater for heating the respective conveyor (14a, 14b) in order to separately melt the first or second material formulation in the first or second conveyor (14a, 14b).
12. A method for producing sleeper soles (52) according to any one of claims 8-11, wherein the first material formulation for the decoupling layer strand (60) comprises a or contains more than one of the following ingredients: - granulated elastomer recyclate, in particular granulated rubber recyclate, in particular made of styrene-butadiene rubber, - a polyolefin, - cable sheath shot, - PET fibers, - a thermoplastic elastomer, in particular urethane-based (TPE / U), - other thermoplastics, - an ethylene polymer wax, and / or - further additives.
13. A method for producing sleeper soles (52) according to claim 12, wherein the grain size of the granulated elastomer recyclate is between 0.01 mm to 4 mm, between 0.1 mm to 1.6 mm 14. A method for producing sleeper soles (52) according to claim 12 or 13, wherein the proportion of the granulated elastomer recyclate is between 50 wt.% and 98 wt%, in particular between 70 wt% and 95 wt%.
15. A method for producing sleeper soles (52) according to any one of claims 12-14, wherein the elastomer recycled granules are melted into a thermoplastic matrix.
16. A method for producing sleeper soles (52) according to any one of claims 9-15, wherein the second material formulation for the adhesion-promoting layer strand (70) contains one or more of the following components: - a polyolefin, - cable sheath shot, - PET fibers, - a thermoplastic elastomer, in particular urethane-based (TPE / U), - other thermoplastics, - processing additives, and / or - further additives.
17. A method for producing sleeper soles (52) according to any one of claims 9-16, wherein the decoupling layer strand (60) and the adhesion-promoting layer strand (70) including its anchor elements (98) are coextruded.
18. A method for producing sleeper soles (52) according to one of the preceding claims, wherein the extrusion device (10) has a calibration (34), a tool outlet (36) and a cooling zone (38) in the region of the profile nozzle (32), wherein the material temperatures in the calibration (34), in the tool outlet (36) and / or in the cooling zone (38) can be adjusted independently of one another.
19. A method for producing sleeper soles (52) according to one of the preceding claims, wherein the extrusion device (10) has a calibration (34), a tool outlet (36) and a cooling zone (38) in the region of the profile nozzle (32), wherein the temperature difference between the calibration (34), the tool outlet (36) and / or the cooling zone (38) can be adjusted independently of one another.
20. A method for producing sleeper pads (52) according to claim 18 or 19, wherein the temperature of the calibration (34) is between 70°Celsius and 120°Celsius, and / or wherein the temperature of the cooling zone (38) is between 0°Celsius and 40°Celsius and / or wherein the temperature difference between the calibration (34) and the cooling zone (38) is greater than 30°Celsius, in particular greater than 70°Celsius.
21. A method for producing sleeper soles (52) according to any one of the preceding claims, wherein the width of the sleeper sole strand (50) is between 150 mm and 400 mm, in particular between 200 mm and 350 mm, and / or wherein the thickness of the sleeper sole strand (50) is between 5 mm and 25 mm, in particular between 8 mm and 20 mm and / or wherein the thickness of the decoupling layer strand (60) is between 4 mm and 20 mm, in particular between 6 mm and 15 mm and / or wherein the thickness of the adhesion-promoting layer strand (70) is between 1 mm and 20 mm, in particular between 2 mm and 10 mm.
22. Sleeper base (52), producible by the method according to one of the preceding claims, for the underside elastic padding of a concrete sleeper (80) for a railway track with ballast bedding, wherein the sleeper base (52) comprises an underside elastic decoupling layer (62) for resting on the ballast bed (82) and an upper side adhesion-promoting layer (72) for anchoring in the concrete of the concrete sleeper (80), wherein the adhesion-promoting layer (72) has anchor elements (98) on its upper side, which are designed to be embedded in the fresh concrete of the concrete sleeper (80) and anchor the sleeper base (52) in the concrete sleeper (80) after the concrete has hardened.
23. An elastically soled concrete sleeper (80) for a railway track with ballast bedding, wherein the concrete sleeper (80) is soled with a sleeper base (52) according to claim 22, wherein the anchor elements (98) of the adhesion-promoting layer (72) are embedded and anchored in the concrete of the concrete sleeper (80).
24. A ballasted railway track comprising railway rails laid on a plurality of elastically soled concrete sleepers (80) according to claim 23, wherein the elastic decoupling layers (62) rest loosely on the ballast bed (82).