EP3380672B1 - Electrically insulated rail - Google Patents

Description

The invention relates to an elastically mounted rail provided with electrical insulation according to the preamble of claim 1 and a method for its preparation according to the preamble of claim 11.

In the case of electrically operated railways, the rails must be insulated because they almost always form a pole of the rail's energy supply. Otherwise, stray currents can cause very undesirable phenomena, especially increased corrosion. This is particularly problematic in the case of rails installed in a substructure, for example in a street, which is very common in municipal railways, such as trams. At the same time, vibration and sound insulation is particularly important there, so that the rails are often elastically supported, for example by means of an elastic rail base profile. This means that the rail moves under static and dynamic loads in the substructure, mainly in the vertical direction, but also laterally, for example due to dynamic forces, such as centrifugal forces when cornering, (rail head deflection). These problems have led to various solutions:
The WO 2004/048696 A1 describes a rail as described at the beginning, also with successively sprayed on electrically insulating and flexible layers. Based on this development, the invention intends to further improve the rail, its manufacture and its use.

The EP 1 206 599 B1 describes a damping profile for grooved rails, which consist of prefabricated, extruded profile halves shaped according to the rail profile, which consist of an electrically insulating elastomeric material, such as a rubber mixture, in practice from plastic-bound particles of car tires. They have air chambers running along the rail below the rail head, which should make the profile so compressible in this area that they can accommodate the vertical deflections. As a result, the profile in this area is considerably thicker than in the area of the rail web.

The EP 2 019 168 B1 describes a grooved rail provided with electrical insulation in the form of a profile including the rail including an elastic rail foot molding, but with the exception of the rail head top and the rail head sides, surrounding profile, which is double-walled in the area of the rail head undersides and the web with longitudinal air chambers. The prefabricated profile is attached to the rail in the area of the head using adhesive strips on both sides. A similar profile shows the EP 2 960 370 A1 .

From the EP 13 31 310 A2 a rail embedding is known in which the rail chambers between the rail head and rail base are completely filled with a profile made of non-elastic material. To distinguish it from the substructure, an elastic layer and a three-dimensional mounting grille are provided. Effective electrical insulation is not provided.

The EP 093 7181 B1 shows a Vigniol rail, on both sides of which there are elastic intermediate layers with hollow chambers. They occupy the entire space between the head and the foot. They are not suitable for ensuring electrical insulation in the subsurface. EP 1 400 628 A2 describes a rail, which is provided with a coating layer made of an electrically insulating and corrosion-resistant material, the coating being covered with a coating of an elastomeric material. DE 197 06 936 A1 discloses a rail for rail vehicles which is encased by an electrically insulating elastomer profile.

Task and solution

The object of the invention is to provide a rail of the type mentioned and a method for its preparation for laying in a substructure, which ensures reliable electrical insulation combined with damping of vibration and sound even after long operating times.

This object is achieved according to the invention by the characterizing part of claim 1 and by the characterizing part of claim 11.

The layer according to the invention thus has a much greater thickness than a coating applied only for corrosion protection and insulation in the manner of a paint finish. The total thickness of the layer is measured in the area of the underside of the rail head / web depending on the maximum vertical and / or lateral deflection of the rail under static and dynamic loads and on the flexibility including volume compressibility and the shear flexibility of the layer. One criterion is that this flexibility of the layer absorbs the maximum deflection or movements of the rail in the layer without affecting the substructure or being damaged by it. The outer skin of the layer should not move relative to the substructure in the area of the rail head underside / web when the rail moves. In the invention, the substructure, particularly in the grooved rail, extends far into the rail chamber formed between the underside of the rail head and the rail foot and is usually made of concrete or asphalt reinforced with ballast, that is to say a quite rigid and inhomogeneous material. Particularly in the area of the web, the flexibility of the layer means that its outer skin does not scratch along the concrete surface, which could not only damage the layer in the web area, but also detach particles from the concrete, which then appear in the gap like emery can scratch the layer and permanently damage it.

This is with the EP 1 206 599 B1 possible because the profile, as can be seen there in Fig. 3, rubs along the substructure during vertical movement in the web area. In the long run, the damping profile would be damaged and the electrical insulation would no longer be guaranteed. The WO 2004/048696 A1 proposes to provide the outer layer with a coating with a low coefficient of friction, for example made of PTFE (plytetrafluoroethylene), in order to prevent the outer layer from adhering to the substructure (see there for FIGS. 15 A and 15 B).

In the two-layer structure according to the invention, the good adhesion of the sprayed-on and hardenable inner layer (preferably made of two-component plastic) and the cohesive connection ensure For example, by applying the outer layer before the inner layer hardens, to ensure that the entire layer is not detached from the rail, both in the case of vertical and load-induced vertical movements and when the rail moves sideways. It is particularly important that the layer, i.e. the outside of the outer layer, adheres to the substructure, i.e. to the part of the in-situ concrete or reinforced asphalt that is brought into the rail chamber after the rail has been laid. Here too, a material or form-fitting connection is to be produced, which can be achieved, for example, by a fibrous or open-pore structure of the outside of the outer layer.

In the invention, it is therefore not only important to avoid damage to the substructure in the region of the underside of the rail head by compressing the layer, but the layer should also absorb the shear forces occurring between the rail and the substructure in the region of the web when the rail moves vertically. The flexibility of the layer must therefore be dimensioned such that the inside of the layer facing the rail web and the outside facing the substructure can shift parallel to one another without the layer being structurally adversely affected or the adhesion to the substructure being impaired. In addition, the flexibility of the layer thick in the web area, and preferably also in the area of the rail head sides, ensures that the substructure is not damaged even when the rail moves laterally, that is to say the rail head deflection mentioned at the beginning. Overall, good vibration and sound damping is thus achieved in addition to the safe electrical insulation.

While conventional systems usually leave the rail foot free and leave the insulation to a rail foot profile on the underside in particular, spraying on the layer also means that the entire rail foot including the bottom of the rail foot, so that the entire rail surface with the exception of the top of the rail head, i.e. the running and groove surface, is effectively insulated and be protected against corrosion. It So there is no need to seal a joint between the elastic rail base profile and the layer.

The rail can be laid ready for installation. The method according to the invention comprises the preparation of the rail surface by blasting and / or priming, then the spraying on of a plastic layer adhering to the rail and curing in a flexible and volume-compressible manner. In one embodiment, the layer can then be supplemented in the area of the underside of the rail head and possibly the rail head side and the web of the rail by further spraying to the required total thickness. However, it is also possible, after the first adhesive layer has been sprayed on, before it has hardened, to press on one or more flexible strips having the properties described above, where they are then securely fixed by the hardening.

The flexible material of the layer should be volume-compressible, preferably by means of embedded, volume-compressible, closed cells. Such a material can easily be processed by spraying, preferably in two-component form, in the manner of a closed-cell, quite solid foam. It is also possible to add other flexible fillers or those that do not hinder the flexibility. In conventional systems, open air chambers, which run in particular along the rail, can fill with liquid and dirt due to the pumping action that arises from every rail deflection, i.e. every wheel axle rolling over it, even if there is only a small opening at one point, for example Rail joints or tie rod attachments. The air chambers then act like hard rods over time and the profiles lose their flexibility, which can lead to their destruction.

The invention thus creates a rail for electrical trains, which can be embedded elastically in a street and its substructure, which usually consists of concrete. The electrical insulation of the rail from the substructure is in the form of an elastic, flexible hardening and, if necessary, provided with fillers Spraying layer securely adhered to the rail surface. In the case of a single-layer structure, the total thickness of the layer is dimensioned such that it can absorb movement of the rail due to load, both by compression and by flexible shear (displacement of the inside and outside of the layer, generally parallel to one another) without damaging the layer and / or the substructure . If the entire thickness of the layer also covers the sides of the rail head, the otherwise necessary joint grouting between the road surface and the rail can be omitted. According to the invention, the layer is composed of an inner and an outer partial layer, from which the inner partial layer is sprayed on and the outer partial layer is applied in the form of a mat to the inner partial layer before it is cured flexibly.

In addition to the claims, the above and further features also emerge from the description and the drawings, the individual features being realized in one embodiment of the invention and being able to represent advantageous embodiments.

Brief description of the drawings

Fig. 1

die Schiene nach der Verlegung im Straßenniveau, jedoch ohne Fugenverguss,

Fig. 2

ein Detail der Schiene von Fig. 1, jedoch mit Fugenverguss.

Exemplary embodiments of the invention are shown schematically in the drawing and are explained in more detail below. In each case, in cross-section, a grooved rail laid in a substructure, such as a street, provided with the insulating layer according to the invention:

Fig. 1

the rail after laying at street level, but without grouting,

Fig. 2

a detail of the track from Fig. 1 but with grouting.

Detailed description of a preferred embodiment

Fig. 1 and 2nd show a grooved rail 11, for example for a tram, with a rail head 12 with a tread 13 for the vehicle wheels (not shown) and a groove 14 for receiving and guiding the wheel flange. The rail head 12 is connected to a wide rail foot 15 by a web 16. The rail foot 15 is supported on an elastic rail foot pad 17, which in turn lies on a base 18. The bottom casting serves to even out the support of the rail foot profile 17 on the relatively coarse concrete support plate 19 underneath.

The rail is surrounded by a two-part layer 20, which consists of an inner layer 51 and an outer layer 52. The inner layer 51 completely surrounds the rail with the exception of the top of the rail head 27, that is to say the running surface 13 and the groove 14. The layer is made by spraying on a 2-component material which adheres well to the surface of the rail and cures flexibly and, if necessary, in a volume-compressible manner, to which radiation for example sand or shot peening, prepared rail surface, preferably by several successive spraying operations. The thickness of the inner layer 51 can vary in individual areas of the rail, but is preferably only so thick that complete electrical insulation of the rail 11 in the substructure 40 is ensured. It also forms an adhesion promoter for the outer layer 52 applied thereafter, which is either also sprayed on or, as shown, pressed on as a strip-shaped mat. It is pressed into the not yet hardened inner layer 51 as a strip made of a flexible and volume-compressible and shear-flexible material and fixed for a short time until the inner partial layer 51 has hardened. The material of the outer layer 52 can be an economically and / or ecologically favorable material, for example recycling material made from car tires, which is made of plastic and possibly with closed micro-gas cells, usually with a bond made from plastics. A natural or artificial fibrous material is particularly preferred, but in addition to the volume compressibility, it must also have sufficient shear flexibility to withstand parallel displacements between the rail and the substructure, ie between the inside of the inner layer 51 and the outside of the 30 outer layer 52 without permanent damage. A fine cross-hatching on the outside 30 indicates that a form-fitting surface structure, for example in the form of fibers, open pores or the like, should be provided at least there. It could also be just a layer containing fibers on the outside of an outside layer containing the previously defined flexibility properties. Particularly suitable plastics for production or use in the outer layer 52 are polyurethane elastomer and epoxy plastics with suitable elasticization. Also random fiber mats, which contain natural fibers or fibers made of plastics such as PP, PA or PE can be used.

If, after laying the rail 11, which is prepared accordingly, the substructure 40 is introduced in the form of concrete and stamped or shaken, the finer concrete components, i.e. cement and sand, will lay around the fibers or in open pores and so on ensure a form and material bond, i.e. an adhesive connection. However, reinforcing constituents of the concrete, such as pebbles 55 or other additives, will also be pressed into the outer side 30 of the outer layer 52, which the latter can withstand thanks to the flexibility of the outer layer. Adhesion of the outer layer to the substructure can also be generated in other ways, e.g. through special adhesion promoters.

The outer layer 52, which is shown in the drawing, extends as Fig. 1 shows, from the outer edge of the rail foot top 23 to the tread, as in Fig. 1 is shown on the left side of the rail. There, if desired, it can form the seal to the road surface 56 with or without joint potting, but usually a joint potting 43 with bitumen or elastic and adhesive plastic is provided, as shown in FIG Fig. 2 shown. It is advantageous if the strip-like mat forming the outer layer 52 has a predetermined tear-off point 57 at the point to which the substructure 40 is to extend. The outer layer 52 then protects the inner layer 51 from buildup when the sub-base concrete is being introduced, but the upper strip 58 can then be easily torn off before the grouting is applied if buildup on the inner layer 51 is prevented there (see Fig. 1 , right side of the rail). The strip-shaped mat forming the outer layer 52 can have recesses 59 in the form of notches at the kinks between the rail head underside 22 and web 16 and the web and rail foot top 23 from the outside 30 to just before their inside, which form the outer layer 52 from a flat strip facilitate.

Fig. 1 shows that a layer corresponding to the outer layer 52 is also applied to the inner layer 51 forming the insulation on the underside 22 of the rail foot in a manner comparable to that on the rail sides which form the rail foot profile 17. It can differ from the rest of the outer layer by other resilience and flexibility values. The measures for imparting adhesion can, however, correspond to those on the remaining outer layer, so that an active connection of the foot profile is created not only to the rail but also to the bottom casting 18.

The rail prepared in this way is embedded in the substructure 40, which surrounds the rail on its rail base profile 17 and the base molding 18 up to close to the top side 27 of the rail head. The substructure 40 consists of a layer of roadway concrete and a much thinner layer of roadway asphalt 42 or another finer surface layer. The road asphalt 42 is sufficient in Fig. 1 not quite up to the rail head side surfaces and there is provided with joint grout 43 made of bitumen or an elastic material, which should also prevent the ingress of moisture between the rail and the substructure.

The method for producing the electrical insulation on the rail can be carried out in a stationary manner in a building yard, but is so relatively easy to carry out that a mobile, for example track-bound processing unit is also possible. The method requires the preparation of the rail surface by blasting, for example by sand or shot blasting, possibly depending on the properties of the layer to be sprayed, the spraying of a primer, then the spraying of the layer 20 in the distribution and layer thickness indicated above. First, the entire surface of the rail to be insulated is provided with the inner layer 51 and then, in one or more further work steps, the outer layer 52, which complements the entire layer 20 to the total thickness 25 in the areas described. In the case of rails that are connected to one another by tie rods prior to installation, they can also be insulated with the same Coating. This also avoids any leaks that could arise if the tie rods were retrofitted.

For execution after Fig. 1 and 2nd After the inner partial layer 51 has been sprayed on, a prepared strip, for example delivered in a roll, of the desired width, i.e. for covering the web and the underside of the rail head and, if appropriate, the rail head sides and the top of the rail foot, is pressed onto the not yet hardened inner layer 51 and forms there the outer layer 52 supplementing the layer 20 to the total thickness 25. This process is relatively easy to carry out since the strip only has to be curved in two dimensions and the notches or recess in 57 support this. Due to the adhesive effect of the inner layer 51, support after pressing is hardly necessary. The strip forming the outer layer 52 also has properties that meet the conditions of flexibility and volume compressibility and the described adhesion-promoting outer side facing the substructure.

The total thickness 25 of the layer is measured on the one hand according to its material properties and on the other hand according to the maximum deflections occurring on the rail caused by loads. These are primarily vertical deflections due to the weight loads and dynamic forces applied by the vehicle wheels, for example, the wheels rattling, for example when braking. However, deflections can also occur to the sides, such as the rail head deflection, which can be caused by lateral thrust in curves or by the wheelsets rolling. These deflections are to be absorbed within the total thickness of the layer 20 both by volume compression, mainly in the area of the rail head underside 24 and the rail head sides 26, and by flexible shear in the area of the web 16, that is to say by a mutual displacement of the in the direction of the layer the rail, for example on the web, adhering inside 29 of layer 20 compared to that of the substructure facing outside 30 of the layer. The total thickness 25 should therefore be such that, as far as possible, there are no longitudinal displacements between the web 16 and the inside 29 and between the outside 30 and the substructure 40. These compressions and shearings or twists in the material should be endured without impairing the material consistency and without damaging it even after a large number of load changes.

Taking these factors into account, a total thickness 25 of the layer 20 in the range between 5 and 15 mm is appropriate, preferably 7 to 10 millimeters. So if a maximum rail deflection in the vertical and / or lateral direction of 2mm is possible and the damage-free compressibility and flexibility is 40%, a total layer thickness of 5mm can be sufficient. If the degree of flexibility is lower and / or the maximum deflection to be feared is greater, the larger specified thickness values can be correct.

Suitable materials for the layer 20 are numerous plastics which can be processed by spraying, have good adhesion to the prepared steel surface and cure flexibly, or by themselves or by means of appropriate fillers such as microspheres, cork powder or the like. are also volume compressible. These include polyurethane elastomers, isocyanates and other polyadditive materials. It is also important that cells contributing to the volume compressibility are closed and that after hardening there is still an outside that provides adhesion to the substructure.

The invention thus provides a grooved rail with an outer skin which is capable of absorbing all movements of an elastically mounted rail without affecting the substructure, damaging it or, more importantly, being damaged by it itself. Above all, with the exception of the tread, the inner layer ensures complete electrical insulation regardless of all other measures. Especially in the vertical Rail deflections, which usually have the larger amplitude, prevent the layer from scratching along the concrete substructure layer which engages in the rail chamber 21 between the rail head 12 and the rail foot 15 and is thereby damaged. The aggregates in the concrete layer have a considerable grinding effect, which can lead to grinding through in the case of the conventional damping profiles, especially in the web area. Fillers, such as pebbles or the like, can also press into the outer skin of the layer when compacting the substructure and hold the layer, so to speak, positively, mainly in the area of the web.

In addition to the safe electrical insulation, the layer applied according to the invention provides excellent damping of the shocks and vibrations to which a rail is exposed and their effects on the substructure and the noise level in the environment and for complete corrosion protection. Although the substructure 40 projects into the rail chambers 21, which are quite large in particular in the case of a grooved rail, and thus a material-consuming filler is avoided, non-destructive absorption is ensured for all rail deflections and vibrations that occur. For example, in the event of a vertical deflection of the rail, the layer in the region of the rail head underside 24 is subjected to compression, on the rail foot top is subjected to tension and in the region of the web 16 and the rail head sides is subjected to shear (and in the opposite direction when the rail swings back). The load conditions for lateral rail deflection (pressure / tension in the area of the web and rail head sides as well as shear in the area of the rail head sides and top of the rail foot) are also opposite.

The rail according to the invention is mainly for laying in a fixed substructure, such as a road or the like. thought. However, it also has advantages when laid in the ground (lawn rail) due to its excellent body, which is stored in the ground against damage, such as pointed stones, and is not leak-prone insulation. the total thickness of the layer can then be reduced to low values. <b> List of reference symbols </b> Grooved rail 11 Rail head 12th Tread 13 groove 14 Rail foot 15 web 16 Rail foot profile 17th Pouring 18th Concrete slab 19th layer 20th Rail chamber 21st Bottom of the rail foot 22 Rail foot top 23 Rail head underside 24th Total thickness 25th Rail head sides 26 Rail head top 27th inside 29 Outside 30th Substructure 40 Road concrete 41 Road asphalt 42 Grouting 43 inner sub-layer 51 outer sub-layer 52 pebble 55 Road surface 56 Target tear point 57 Upper strip 58 Recesses 59

Claims (12)

1. An elastically mounted rail, provided with electrical insulation, in particular a grooved rail (11), which has a rail head (12), a rail base (15) and a rail web (16) connecting these,
   wherein the rail is embedded in a substructure (40), e.g. in concrete, wherein the rail is provided with an electrically insulating layer (20) applied before installation, which has adhesion to the rail surface by means of spraying,
   wherein the layer (20), which has an overall thickness (25) of at least 4 mm at least in the region of the rail head lower side (24) and the rail web (16), is adhesively and firmly connected in a form-fitting manner to the substructure (40) on its outer side (30) and is compressible in volume and inherently shear-flexible in such a manner that the maximum vertical and/or lateral deflections of the rail (11) can be permanently received without damage in the case of static and dynamic loads in the case of adhesion of the layer (20) both to the rail (11) and also to the substructure (40), characterized in that the layer (20) is constructed from an inner and an outer partial layer (51, 52), of which the inner partial layer (51) is sprayed on and the outer partial layer (52) is a mat firmly connected to the inner partial layer (51).
2. The rail according to Claim 1, characterized in that the overall thickness (25) of the layer (20) in the region of the rail head lower side/web (24, 16) is between 5 mm and 15 mm, preferably between 7 mm and 10 mm.
3. The rail according to Claim 1 or 2, characterized in that the layer (20) also has the overall thickness (25) in the region of the rail head sides (26).
4. The rail according to one of the preceding claims, characterized in that the layer (20) has a structure and/or consistency that is adhesion-promoting with the substructure (40) on its outer side (30) facing the substructure.
5. The rail according to Claim 4, characterized in that the adhesion-promoting structure is fibrous.
6. The rail according to one of the preceding claims, characterized in that the layer (20), in particular the outer layer (52), contains embedded, closed cells compressible in volume.
7. The rail according to one of the preceding claims, characterized in that the overall thickness of the layer (20) in the region of the rail web (16) is at least the same as the overall thickness in the region of the rail head lower side (24).
8. The rail according to Claim 6 or 7, characterized in that the outer layer (52) is a mat containing fibres at least on its outer side (30).
9. The rail according to one of Claims 6 to 8, characterized in that the outer layer (52) has a setpoint separation point (57) in a region adjacent to the rail surface, which setpoint separation point (57) delimits a strip (58), which can be removed for applying a joint sealant (43).
10. The rail according to one of the preceding claims, characterized in that the inner layer (51) also surrounds the rail base (15), preferably the entire rail (11) apart from the rail head upper side (27).
11. A method for preparing a rail (11) having electrical insulation for installation in a substructure (40), e.g. in concrete, which rail (11) has a rail head (12), a rail base (15) and a rail web (16) connecting these, in particular a grooved rail (11), having a flexible layer (20), characterized by the following method steps:

    - preparing the rail surface by means of beams and/or primers,

    - spraying a curable inner layer (51) containing plastic, possibly provided with fillers and adhered to the rail (11), in a lower thickness than an overall thickness (25) onto the rail surface with the exception of the rail head upper side (27) and

    - onto the region of the rail head lower side/web (24, 16) and possibly the rail head sides (26), and

    - applying an outer layer (52) in the form of a mat with a greater thickness to the inner layer (51) in a firm and adhesive manner prior to the curing thereof, which together with the inner layer produces an overall thickness (25), wherein

    the outer layer (52), which is compressible in volume and inherently shear-flexible and is intended for permanently receiving the maximum vertical and/or lateral deflections of the rail without damage in the case of static and dynamic loads in the case of adhesion of the layer (20) both to the rail and also to the substructure, is applied such that a side to be adhesively and firmly connected in a form-fitting manner to the substructure (40) points to the outer side (30).
12. The method according to Claim 11, characterized in that a flexible layer (17) is applied to the inner layer (51) ensuring electrical insulation in the course of producing the rail in the region of the rail base lower side.

Images