EP2776627B1

EP2776627B1 - Sleeper with an elastic sole on ballast bed

Info

Publication number: EP2776627B1
Application number: EP12794162.3A
Authority: EP
Inventors: Patrick Carels
Original assignee: Pandrol Cdm Track Nv
Current assignee: Pandrol Cdm Track Nv
Priority date: 2011-10-21
Filing date: 2012-10-22
Publication date: 2018-02-07
Anticipated expiration: 2032-10-22
Also published as: ES2666280T3; BE1020231A3; WO2013082679A1; EP2776627A1; PL2776627T3; NO2776627T3; DK2776627T3

Description

The invention concerns a railway that comprises an elastic sole with a sleeper, in particular a concrete sleeper, on which the rails of the railway are to rest, whereby said elastic sole is designed to be placed between the sleeper and a ballast bed in a close-fitting manner and whereby the elastic sole is fixed to the bottom of the sleeper.
In such a railway, rails are mounted on top of sleepers. The sleepers are placed on the ballast bed and preferably partially embedded therein. The ballast bed is formed of chippings, also called ballast stones, and ensures the stability of the railway and absorbs vibrations.
In order to dampen vibrations of the rails and sleepers towards the underlying railway bed, elastic soles are placed between supports of the sleepers and the ballast bed according to the present state of the art. This restricts noise pollution and also avoids damage to the ballast bed. Examples of existing elastic soles are described in patents EP1186709B1 and EP1298252B1 .
The elasticity of this type of track is mainly determined by the ballast bed, the elastic sole between the sleeper and the ballast bed and possibly also by an elastic sole between the rail and the sleeper. As the ballast bed is silted up by dirt and /or sand in this system, this results in an undesirable reduction in the elasticity of the track.
The use of the above-mentioned elastic soles between the sleeper and the ballast bed further results in certain cases, depending on the stiffness of such soles, in a reduced stiffness of the track, as a result of which the lateral tracking stability is adversely affected.
The lateral tracking stability is largely determined by the lateral resistance to displacement of the sleeper in relation to the ballast bed. This lateral resistance determines the force required for a track to move back and forth about the ballast bed. Hence, this also determines the resistance with which a track opposes a transverse displacement.
Said problems arise in particular with railways for high speed lines (HSL).
Patent application EP2108738A1 describes an elastic sole whereby the contact between the sole and the ballast bed is improved by providing the sole with teeth formed of ballast stones. The manufacture of such a sole is rather laborious. Also these teeth constitute a difficulty, for example when stacking and transporting the sleepers.
International patent application WO2011/020467 further describes an elastic sole formed of different parts with different elasticities which are selected such that the compression of the sole is equal over the entire sleeper. This will only improve the lateral tracking stability to a very limited extent. Patent application JP-A-408338001 describes a support box including elastic pads for supporting the sleeper on the ballast stones.
The invention aims to remedy these disadvantages by putting forward an elastic sole and a method making it possible to provide the bottom of the sleepers, in particular of concrete sleepers, with an elastic sole in a simple manner, whereby a reduction of the lateral tracking stability, which is caused by the elastic sole, is restricted. Moreover the proposed solution makes it possible to apply the elastic sole in such a way that a stiffening caused by the ballast bed silting up is prevented.
To this aim, the bottom of the elastic sole has a relief to at least partially enclose the chippings of the ballast bed on which the elastic sole rests, as a result of which the lateral resistance against displacement of the sleeper in relation to the ballast bed is increased, as claimed in the appended claims. Further, the elastic sole preferably extends over practically the entire bottom of the sleeper.
Practically, the relief contains upright parts consisting of elastically deformable studs which are to extend at least partially with a free end between the chippings of the ballast bed, and the relief thus contains corresponding cavities, formed between said studs, in which the chippings of the ballast bed at least partly penetrate.
Further, these cavities have a size which preferably corresponds to the average size of the stones of the chippings of the ballast bed. The free ends of two adjacent studs are hereby situated at a distance from one another in the same order of magnitude as the average diameter of the stones of the chippings.
Advantageously, the relief consists at least partly of an undulating surface which is undulating in two directions that are practically perpendicular to one another.
In a very advantageous manner, the stiffness of the elastic sole under rail fastening zones, provided on the upper side of the sleeper, is higher than the stiffness of the elastic sole under the sleeper between said rail fastening zones.
The invention also concerns a method for manufacturing a railway with sleepers on whose top rest rails, whereby these sleepers rest on a ballast bed with ballast stones via elastic soles, whereby at least one elastic sole is fixed to the bottom of the sleeper, which elastic sole has a relief on its bottom side which is placed against the ballast bed in such a way that the relief at least partly encloses a part of the ballast stones of the ballast bed in order to increase the lateral resistance of the sleeper in the ballast bed. According to this method, said elastic sole is made of the same elastic material as the relief. The relief is selected such that it has elastically deformable standing studs, whereby, in order to partly enclose a ballast stone of the ballast bed, at least three studs abut against said partly enclosed ballast stone. Further, almost the entire bottom side of the sleeper is preferably coated with at least one elastic sole applied thereto.
Other particularities and advantages of the invention will become clear from the following description of practical embodiments of the method and device according to the invention; this description is given as an example only and does not restrict the scope of the claimed protection in any way; the figures of reference used hereafter refer to the accompanying drawings.

Figure 1 is a schematic representation of a cross section of an elastic sole with a concrete sleeper according to a preferred embodiment of the invention.
Figure 2A is a schematic representation of a cross-sectional detail of figure 1.
Figure 2B is a schematic perspective representation of a detail of the relief of the elastic sole from figure 1.
Figure 3 shows schematic representations of the bottom side of a sleeper with an elastic sole according to different embodiments of the invention.

The invention generally concerns a railway comprising a sleeper on which rails of the railway rest, preferably a concrete sleeper. This sleeper is provided with one or several elastic soles on its bottom side on which the sleeper rests, as is schematically represented in figure 1. The elastic soles 1 are situated in a railway between the sleeper 2 and a railway bedding formed of a ballast bed 4 with chippings 9. The sleepers 2 thus rest on the ballast bed 4 via the elastic soles 1.
These elastic soles 1 are preferably provided with a bottom side 7 having a relief 8 that makes contact with the chippings 9 of the ballast bed 4. The elastic sole 1 hereby has a base with a thickness which preferably amounts to at least 5 mm, with upright parts on it, whose height preferably amounts to 2 to 15 mm and which form the relief 8 which is turned towards to the ballast bed 4. The upright parts thus extend towards the ballast bed 4. Consequently, the relief 8 has cavities in which chippings 9 of the ballast bed 4 can at least partly penetrate and/or it has upright parts in between which chippings 9 of the ballast bed 4 can at least partly take place. The elastic sole 1 thus partly encloses part of the chippings 9. The cavities and/or upright parts thus enlarge the contact surface of the elastic sole 1 with the ballast bed 4. The relief 8 forms standing contact surfaces which partly ensure an enlargement of the contact surface with the ballast bed 4 and also provide for an increase of the horizontal shear resistance. Compared to a flat elastic sole 1 without relief 8, this results in an improved lateral stability of the railway.
The size of said cavities preferably corresponds to the size, in particular the average size, of the stones of the chippings 9. The width of the cavity is hereby preferably in the same order of magnitude as the average diameter of the stones of the chippings 9. Further, the height of the relief 8 is preferably smaller than the average diameter of the stones of the chippings 9. As a result, the chippings 9 situated in a cavity will always make contact with at least one standing contact surface of the relief 8 of the elastic sole 1 and with underlying chippings 9 that are not situated in the cavity.
The elastic soles 1 extend against the bottom side 6 of the sleeper 2, under the fastening zones 13 for the rails 3 and preferably also against the bottom side 6 of the sleeper 2 between said fastening zones 13. Thus, the elastic soles 1 preferably extend under practically the entire sleeper 2. Preferably, the stiffness of the elastic soles 1,17,18 under the fastening zones 13 is higher than the stiffness of the elastic soles 1,19 between said fastening zones 13. As a result, the action of the elastic soles 1,17,18, which preferably serve as main supports under the rail fastening zones 13, is practically not affected.
Further, the invention also concerns a method for manufacturing a railway with such sleepers 2 and elastic soles 1 on a ballast bed 4. According to this method, the lateral resistance of the sleeper 2 in the ballast bed 4 is increased. The relief 8 of the elastic sole 1 with its uneven surface provided with studs takes care of that. The unevennesses of the studs thus create peaks and dips on the surface of the elastic sole 1. According to the method, ballast stones attach themselves in the dips, and the peaks additionally provide resistance against a lateral displacement of the elastic sole 1 and sleeper 2 in relation to the ballast bed 4.
According to a first preferred embodiment of the invention, the bottom side 6 of a concrete sleeper 2 is provided with an elastic sole 1 over practically its entire length, as is shown in figures 1, 2A, 2B, 3A and 3B. The elastic sole 1 may hereby either be glued, for example with its top side 5, to the bottom side 6 of the sleeper 2, or the top side 5 of the elastic sole 1 may for example be provided with upright parts which are embedded in the bottom side 6 of the sleeper 12, such that the sole 1 is anchored in the bottom side 6 of the sleeper 2.
On the top side 16 of the sleeper 2, at each of the far ends 22, is situated a rail fastening zone 13. The rails 3 of the railway are to be fixed on the sleeper 2 in this zone 13.
At the height of these rail fastening zones 13, a first and a second elastic sole 17,18 are applied to the bottom side 6 of the sleeper 2. These first and second elastic soles 17,18 form supports under the rail fastening zones 13 with which the sleeper 2 rests on the ballast bed 4.
The first and second elastic soles 17,18 are provided with a relief 8 on their bottom side 7 which is turned towards the ballast bed 4, as represented in figure 2A. This relief 8 is undulating in two directions that are practically perpendicular to one another, as shown in more detail in figure 2B. These directions may be oriented according to the longitudinal axis of the sleeper 2 and perpendicular to this longitudinal axis. As a result, the relief 8 has upright parts formed of standing, truncated, substantially conical studs 10. These studs 10 have obliquely upright contact surfaces 14 forming an angle α with the plane of the bottom side 6 of the sleeper 2 which amounts to 5° to 85°, and preferably 10° to 30°. The relief 8 has a height A which corresponds to the height of said standing studs 10 and amounts to practically 2 to 15 mm, preferably 5 to 10 mm. Thus, the height A of the relief 8 is the difference in height between a top 15 of the studs 10 and a dip 23 between these studs 10. Said top 15 corresponds to the free end of the upright part or also the stud 10.
Preferably, said free ends 15 of two adjacent studs 10 are hereby situated at a distance E from one another which is in the same order of magnitude as the average diameter D of the chippings 9. By the same order of magnitude is meant that the distance E between the free ends 15 preferably amounts to maximally four times the average diameter D of the chippings 9 and minimally one fourth of the average diameter D of the chippings 9. In particular, said distance E preferably amounts to maximally two times the average diameter D of the chippings 9 and minimally half of the average diameter D of the chippings 9.
Adjacent studs 10 thus define a cavity which contains the chippings 9. The distance E between the free ends 15 hereby corresponds to the width of said cavity.
The thickness C of the elastic sole 17,18 at the height of the tops 15 of the studs 10 preferably amounts to 7 to 20 mm. The thickness B at the height of the dips 23 between the studs 10 preferably amounts to minimally some 5 mm. Further, the distance E between two successive tops 15 of the studs 10 preferably amounts to some 20 to 100 mm.
Between these first and second elastic soles 17,18, a third elastic sole 19 is placed against the bottom side 6 of the sleeper 2. This third elastic sole 19 preferably abuts against the first and second elastic soles 17,18, and this third sole 19 preferably has a base with a thickness B which is practically equal to the thickness B of the base of the first and second elastic soles 17,18. Thus, the thickness B of the base of the third elastic sole 19 preferably amounts to minimally some 5 mm as well.
According to this first embodiment, the third sole 19 may possibly be also provided with standing studs 10 analogous to those of the first and second soles 17,18, as represented in figure 3B. The elastic sole 1 on one far end 22 of the sleeper 2 is thus provided with relief 8, whereas the elastic sole 1 in the centre 21 of the sleeper 2 may be flat or may also be provided with some relief 8.
The material of the elastic soles 1,17,18,19 is selected such that the stiffness of the first and second elastic soles 17,18 in relation to the stiffness of the third elastic sole 19 has a ratio that is greater than a factor 2.
Such materials are known as such to the professional and may, for example, consist of recycled rubber, natural or synthetic rubber, resin-bound rubber granules, thermoplastic elastomer (TPE), polyvinyl chloride (PVC) and/or ethylene vinyl acetate (EVA). The stiffness of the elastic soles 1,17,18,19 may be influenced, for example, by an appropriate density of the material used. Possibly cavities can also be provided so as to reduce the stiffness, not represented in the figures. Further, the elastic sole 1,17,18,19 may also contain a woven structure so as to reinforce the sole, not represented in the figures.
Said elastic soles 1,17,18,19 with the relief 8 can be manufactured according to methods known as such, such as for example vulcanization, extrusion or protrusion. The elastic sole 1,17,18,19 is manufactured together with the studs 10, preferably in one piece.
The elastic soles 1,17,18 rest with their bottom sides 7, provided with the relief 8, on the chippings 9 of the ballast bed 4. The chippings 9 are hereby at least partly surrounded by the elastic soles 1,17,18, and these chippings 9 thus at least partly fill the cavities in the relief 8. Consequently, the standing studs 10 extend towards the bottom between the chippings 9. The free end 15 of the studs 10 thereby extends between the chippings 9. The obliquely upright contact surfaces 14 hereby rest against the chippings 9. As a result, the lateral stability of the railway is strongly improved.
Further, by providing a third sole 19 next to the first and second soles 17,18, the contact surface with the ballast bed 4 is raised further, such that this third sole 19 also has a positive effect on the lateral stability of the railway. This effect is further increased if the third sole 19 is also provided with a relief 8 analogous to that of the first and second soles 17,18, as represented in figure 3B.
The third sole 19, situated between the first and second soles 17,18 and between the bottom side 6 of the sleeper 2 and the ballast bed 4, also prevents the railway from stiffening due to a possible accumulation of dirt and/or sand between the bottom side 6 of the sleeper 2 and the ballast bed 4.
Moreover, by selecting a much lower stiffness for the third sole 19 compared to that of the first and second elastic soles 17,18, the third sole 19 will have practically no effect whatsoever on the action of the first and second elastic soles 17,18.
A second preferred embodiment of the invention, not represented in the figures, differs from the first embodiment in that the bottom side 7 of at least the first and the second elastic soles 17,18 is provided with a relief 8 consisting of pyramid-shaped studs 10. These pyramid-shaped studs 10 can possibly be truncated.
An embodiment of the invention, not represented in the figures, differs from the preceding embodiments in that the elastic sole 1 is made in one piece with the first, the second and the third elastic soles 17,18,19, whereby this elastic sole 1 is provided with one of the aforementioned relief shapes 8 at least under the rail fastening zones 13 on the far ends 22 of the sleeper 2.
Another embodiment of the invention, not represented in the figures, differs from the preceding embodiments in that there is not applied any elastic sole 19 under the centre 21 of the sleeper 2, but merely an elastic sole 17,18 with relief 8 under the sleeper 2 at the height of the rail fastening zones 13.
According to still another embodiment of the invention, not represented in the figures, an elastic sole 19 with a bottom side 7 provided with a relief 8 is applied under the centre 21 of the sleeper 2 between elastic soles 17,18 having a flat bottom side 7. Thus is provided an elastic sole 1,17,18,19 under the entire sleeper 2. The elastic sole 19 under the centre 21 of the sleeper 2 is hereby more flexible than the elastic soles 17,18 which are provided under the rail fastening zones 13. The elastic sole 19 under the centre 21 of the sleeper 2 will improve the lateral stability of the railway and also prevents the railway from stiffening by preventing the railway bed under the sleeper 2 from silting up.
An embodiment of the invention, represented in figure 3C, differs from the preceding embodiments in that only a first and second elastic sole 17,18 are provided under the rail fastening zones 13, whereby the bottom side of these soles 17,18 is provided with a relief 8, without a third elastic sole 19 being provided in the centre 21 of the sleeper 2 as well.
The invention also concerns a method for installing a railway with sleepers 2 whereby rails 3 rest on the top side 16 thereof as described above and whereby these sleepers 2, via elastic soles 1,17,18,19, rest on a ballast bed 4 with chippings 9. In this method, at least one elastic sole 1,17,18,19 is applied against the bottom side 6 of the sleeper 2. This elastic sole 1 has a relief 8 on its bottom side 7 which is placed against the ballast bed 4 and which partly encloses at least a part of the chippings 9 of the ballast bed 4.
According to this method, the elastic sole 1,17,18,19 is manufactured together with the relief 8 out of one and the same elastic material. Elastic studs 10 are being provided thereby, such that the size of the cavity between adjacent studs 10 corresponds to the size of the stones of the chippings 9. The size of the cavity is preferably selected such that at least three studs 10 abut against a stone of the chippings 9 enclosed in the cavity.
According to a method of the invention, practically the entire bottom side 6 of the sleeper 2 is coated over at least its entire length with at least an elastic sole 1 applied to the latter.
Naturally, the invention is not restricted to the above-described method and device according to the invention. Thus, the relief 8 on the bottom side 7 of the elastic soles 1 may consist of all sorts of profiles and patterns whereby upright parts 10 can penetrate at least partly between the chippings 9 of the ballast bed 4, as defined by the appended claims. Thus, also the bottom side 7 of the elastic soles 1,17,18,19 may possibly be only partly provided with a relief 8.

Claims

Railway comprising a sleeper (2) with an elastic sole (1) placed on an underlying ballast bed (4) with chippings (9) on which the rails (3) of the railway are to rest, whereby the sleeper (2) rests on the elastic sole (1) which is supported by the ballast bed (4), whereby the elastic sole (1) has a top side (5) which is fixed to a bottom side (6) of the sleeper (2), whereby the elastic sole (1) has a relief (8) on a bottom side (7) of the elastic sole (1) increasing the lateral resistance against displacement of the sleeper (2) in relation to the ballast bed (4), and whereby the relief (8) comprises upright parts which at least partly extend with a free end (15) between the chippings (9) of the ballast bed (4) so that the elastic sole (1) at least partly encloses stones of the chippings (9), characterised in that the upright parts consist of elastically deformable studs (10).
Railway according to claim 1, whereby stones of said chippings (9) have an average diameter (D) and whereby the free ends (15) of two adjacent studs (10) are situated at a distance (E) from one another which is in the same order of magnitude as the average diameter (D) of the chippings (9).
Railway according to claim 1 or 2, whereby said studs (10) narrow towards their free ends (15), whereby said studs (10) are preferably practically conical or pyramid-shaped.
Railway according to anyone of claims 1 to 3, whereby said relief (8) is at least partly formed of an undulating surface which is undulating in two practically perpendicular directions in relation to one another.
Railway according to anyone of claims 1 to 4, whereby said relief (8) extends at least under a rail fastening zone (13) of the sleeper (2) where rails are to be fixed on the sleeper (2).
Railway according to anyone of claims 1 to 5, whereby the relief (8) has obliquely upright contact surfaces (14) forming an angle (α) with the bottom side (6) of the sleeper (2) which amounts to 5° to 85°, preferably 10° to 30°.
Railway according to anyone of claims 1 to 6, whereby the stiffness of the elastic sole (1) under rail fastening zones (13) provided on the top side (16) of the sleeper (2) is higher than the stiffness of the elastic sole (1) under the sleeper (2) between the rail fastening zones (13).
Method to increase the lateral resistance against displacement of a sleeper (2) in relation to a ballast bed (4) when manufacturing a railway with a rail (3) resting in at least a rail fastening zone (13) on a top side (16) of the sleeper (2), which sleeper (2) rests on the ballast bed (4) with chippings (9), whereby at least an elastic sole (1) is provided between the sleeper (2) and the ballast bed (4), the method comprising the steps of
- applying at least one elastic sole (1) against a bottom side (6) of the sleeper (2), which is turned towards the ballast bed (4),

- providing this elastic sole (1) with a relief (8) which is manufactured together with the elastic sole (1) out of one and the same elastic material and

- placing the relief (8) against the ballast bed (4),
characterised in partly enclosing at least a part of the chippings (9) of the ballast bed (4) by this relief (8) by at least three elastically deformable standing studs (10) of the relief (8) abutting against a partly enclosed stone of the chippings (9).
Method according to claim 8, whereby practically the entire bottom side (6) of the sleeper (2) is coated with at least one elastic sole (1).
Method according to claim 9, whereby the elastic sole (1) in the centre (21) of the sleeper (2) is selected more flexible than the elastic sole (1) at a far end (22) of the sleeper (2).
Method according to claim 10, whereby said elastic sole (1) is selected with a stiffness which is at least a factor 2 lower in the centre (21) of the sleeper (2) than at a far end (22) of the sleeper (2).
Method according to anyone of claims 8 to 11, whereby under a first and a second rail fastening zone (13) of the sleeper (2) is applied at least a first (17) and at least a second elastic sole (18) respectively against the bottom side (6) of the sleeper (2).
Method according to claim 12, whereby between these first and second elastic soles (17,18) is applied at least a third elastic sole (19) between the rail fastening zones (13) against the bottom side (6) of the sleeper (2).
Method according to claim 13, whereby the stiffness of this third elastic sole (19) is selected such that it is lower than the stiffness of the first and the second elastic soles (17,18).