Patent Application
20250163652
This application claims priority from Austrian Patent Application No. A 136/2023, filed Nov. 22, 2023, which is incorporated herein by reference as if fully set forth.
The present invention relates to a turnout for a track system for rail vehicles, having a main track and at least one branch track that joins the main track, wherein the main track and the branch track at least in regions have in each case at least two rails, wherein the rails are fastened on sleepers and the sleepers are mounted on a ballast bed, wherein disposed between the sleepers and the ballast bed, on the lower sides of the sleepers that point towards the ballast bed, are in each case sleeper pads which have in each case at least one elastomer layer, and the turnout has a turnout frog tip in which the rails of the main track pointing towards the branch track and the rails of the branch track pointing towards the main track converge, wherein a turnout frog region extends so as to proceed from the turnout frog tip in mutually opposite directions, wherein the sleepers in the turnout frog region are designed as inherently continuous sleepers on which the rails of the main track as well as the rails of the branch track are fastened, and wherein the turnout frog region, proceeding from the turnout frog tip, extends in the mutually opposite directions in each case at most over twenty-five successive sleepers.
Turnouts in track systems represent crossover points in which at least one branch track leads into a main track, or leads out of the latter, respectively. There are so-called simple turnouts in which a branch track leads out of a main track, or leads into the latter, respectively. However, there are also so-called slip switches in which a branch track crosses a main track and by way of the latter leads outwards on both sides.
In the prior art it is known to equip tracks with elastomer layers in the region between the turnouts as well as in the region of the turnouts, so as to achieve smoothing of a rail subsidence and damping of vibrations when a train travels thereon. For example, it is known to dispose so-called sleeper pads with such elastomer layers below the sleepers. In this way, these sleeper pads are located between the sleeper and a ballast bed on which the respective sleeper lies. Sleeper pads are known from, for example, AT 506 529 B1 and WO 2016/077852 A1. Proposed in AT 506 529 B1 is, for example, a sleeper pad in which a randomly oriented fibrous layer is attached to the side that points towards the sleeper on an elastic layer of the sleeper pad, and a protective layer and a further elastic layer are attached to the opposite side. The randomly oriented fibrous layer serves for fastening the sleeper pad to the sleepers cast from concrete. The protective layer on the other side of the sleeper pad delimits the ingress of ballast of the ballast bed into the sleeper pad to the desired degree.
Known in the prior art are however also elastic intermediate tiers on the sleeper upper side, thus between the rail and the sleeper. This is described in EP 0 552 788 A1, for example.
Shown in AT 503 772 B1 is a turnout in which sleeper pads having at least one elastomer layer are in each case disposed on the sleeper lower sides of the sleepers. In AT 503 772 B1, intermediate tiers, which are referred to as fastening means in this document, are located between the rails and the sleepers. It is furthermore known from AT 503 772 B1 to vary the softness or hardness of the sleeper pads over the length of the sleeper.
For optimizing the rail subsidence when a train travels thereon, on the one hand, and for damping vibrations, on the other hand, it is proposed in AT 520 697 B1 to implement two mutually distanced elastic planes by means of sleeper pads and intermediate tiers.
One issue that has not been satisfactorily solved to date is shocks or vibrations, and also a certain noise emission, which are created when rail vehicles travel over the so-called turnout frog gap. The turnout frog gap is a gap in the tracks that is adjacent to the turnout frog tip. Here, the wheels of the respective rail vehicle traveling over this turnout frog gap hit the turnout frog tip or hit the opposite appendage of the tracks, depending on the direction of travel. This leads to shocks or vibrations, as well as to a certain noise emission. This phenomenon becomes all the worse the more the turnout is worn out in the turnout frog region, and/or the more worn the wheels of the rail vehicle are.
It is an object of the invention to propose an improvement for a turnout mentioned at the outset, by way of which the creation of shocks and noise emission due to travelling over the turnout frog gap can be counteracted.
In order to achieve this object, the invention, proceeding from a turnout of the type mentioned at the outset, proposes that the respective elastomer layers of the respective sleeper pads of the sleepers in the turnout frog region are softer than the respective elastomer layers of the respective sleeper pads in regions of the turnout in front of and behind the turnout frog region.
Owing to the softer design embodiment of the elastomer layers of the respective sleeper pads in the turnout frog region, which is softer in comparison to the regions in front and behind the latter, the creation of noise and shocks at the turnout frog gap, thus in other words the creation of audible as well as perceptible impact noise, can be significantly reduced. It is at first astonishing for the person skilled in the art that this measure is possible, because he/she would have to anticipate significantly higher rail subsidence in the turnout frog region owing to the softer elastomer layers. It has however been surprisingly demonstrated that no excessive rail subsidence has to be anticipated when the relatively soft sleeper pads are restricted to a spatially very limited region, specifically the turnout frog region. In this way, a positive reduction of the creation of noise as well as shocks is achieved by the invention, while simultaneously adequately smoothing the rail subsidence.
In this context, it is particularly favourable when the turnout frog region, proceeding from the turnout frog tip, extends in the mutually opposite directions in each case at most over fifteen, preferably in each case at most over five, successive sleepers. Generally speaking, the length of the turnout frog region here has to be adapted to the speeds at which the turnout is travelled over by the respective rail vehicle. In the case of high speed lines, the turnout frog region is longer than in the case of lines in which the rail vehicles only travel over the turnout at lower speeds.
In turnouts according to the invention, intermediate tiers, which are known per se in the prior art, may or may not be present between the tracks and the sleepers lying below the latter. The intermediate tiers do not have any major significance in terms of the effect of reducing noise and vibrations that is achieved according to the invention. Said intermediate tiers can be designed as in the prior art. The intermediate tiers between the respective rail and the respective sleeper in the turnout frog region are favourably significantly harder than the sleeper pad, or the elastomer layer of the latter, disposed below the respective sleeper.
A physical parameter by way of which the softness of the elastomer layer of the respective sleeper pad can be described particularly well is the dynamic bedding modulus which per se is a function of frequency. The low-frequency range here is responsible for ensuring that vertical deformation of the superstructure is as low as possible, thus rail subsidence is as low as possible, when the rail vehicles travel thereover. In this context, it is favourably provided that the respective elastomer layers of the respective sleeper pads of the sleepers in the turnout frog region at a measurement frequency of 10 Hz (Hertz) have in each case a dynamic bedding modulus in the range from 0.088 N/mm3 (Newton per cubic millimetre) to 0.186 N/mm3, preferably from 0.091 N/mm3 to 0.181 N/mm3. At 10 Hz, this dynamic bedding modulus is particularly preferably in the range from 0.095 N/mm3 to 0.176 N/mm3. The dynamic bedding modulus at 10 Hz can also be referred to as the low-frequency dynamic bedding modulus.
For the damping of the audible as well as perceptible impact noise to be achieved by way of the invention, it is favourable to consider the dynamic bedding modulus of the elastomer layer at the higher frequency range. A lower limit of the presently relevant frequency range is 20 Hz, while an upper limit is 160 Hz. In this context, it is therefore preferably provided in the invention that the respective elastomer layers of the respective sleeper pads of the sleepers in the turnout frog region at a measurement frequency of 20 Hz have in each case a dynamic bedding modulus in the range from 0.17 N/mm3 to 0.42 N/mm3, preferably from 0.18 N/mm3 to 0.40 N/mm3. At 20 Hz, this dynamic bedding modulus is particularly preferably in the range from 0.19 N/mm3 to 0.39 N/mm3. The dynamic bedding modulus at 20 Hz can also be referred to as the higher-frequency dynamic bedding modulus at 20 Hz.
With reference to the upper limit mentioned it is preferably provided that the respective elastomer layers of the respective sleeper pads of the sleepers in the turnout frog region at a measurement frequency of 160 Hz have in each case a dynamic bedding modulus in the range from 0.21 N/mm3 to 0.53 N/mm3, preferably from 0.22 N/mm3 to 0.51 N/mm3. At 160 Hz, this dynamic bedding modulus is particularly preferably in the range from 0.23 N/mm3 to 0.48 N/mm3. The dynamic bedding modulus at 160 Hz can also be referred to as the higher-frequency dynamic bedding modulus at 160 Hz.
The dynamic bedding modulus mentioned of the respective elastomer layer of the respective sleeper pad at 10 Hz, 20 Hz and also at 160 Hz can be determined according to the standard DIN EN 16730:2016-09 according to track category TC3.
In the region in front of and behind the turnout frog region, the respective elastomer layers of the respective sleeper pads of the sleepers at the respective measurement frequency favourably have in each case a dynamic bedding modulus which is higher by at least a factor of 1.25, preferably by at least a factor of 2.0, than the respective elastomer layers of the respective sleeper pads of the sleepers in the turnout frog region. The designations in front of and behind the turnout frog region here relate to the direction of travel in which the rail vehicle travels over the turnout. It is irrelevant here whether the rail vehicle comes from the main track and continues on the main track, or comes from the branch track and continues on the main track, or comes from the main track and continues on the branch track, or remains on the branch track when travelling over the turnout. The latter is of course only possible when the turnout according to the invention is a so-called slip switch in which the branch track crosses the main track and leads out of the latter on both sides. For the sake of completeness, it is thus once again pointed out at this point that turnouts according to the invention can be simple turnouts as well as slip switches.
In particularly preferred design embodiments it is provided that the respective elastomer layers of the respective sleeper pads comprise or are composed of polyurethane and/or natural rubber. The respective elastomer layers can thus be composed completely of polyurethane and/or of natural rubber, or else comprise additional components.
The sleeper pad, in addition to the elastomer layer, can have a binding layer which points towards the sleeper and serves for fastening the sleeper pad to the sleeper. For this purpose, there are a wide range of possibilities in the prior art, which may also be applied to the invention. The binding layer can thus be, for example, a pure adhesive bond or else a layer of textiles, randomly oriented fibres or flock fibres, or the like. The entire range of possibilities known in the prior art is available here.
Moreover, the respective sleeper pad can also have a protective layer which points towards the ballast bed. As is known per se in the prior art, this protective layer is used whenever the elastomer layer has to be protected against excessive ingress of the ballast, or against any other destruction by the ballast. Here too, the possibilities known per se in the prior art may be utilized.
When viewed in the longitudinal direction of the sleeper pad, or of the sleeper, respectively, the elastomer layers can also be designed to be continuous, thus to be identical throughout, in the turnout frog region. However, the sleeper pads in the turnout frog region, when viewed in their longitudinal extent, can also have regions of different softness. It can thus be provided, for example, that the respective elastomer layers of the respective sleeper pads of the sleepers in the turnout frog region, in the direction of a longitudinal extent of the respective sleeper, have in each case a central region and adjacent thereto two outer regions. In this case, it is particularly favourable when the respective elastomer layers of the respective sleeper pads of the sleepers in the turnout frog region are in each case softer in their central region than in the respective two outer regions adjacent thereto.
Further features and details of preferred design embodiments of the invention will be explained hereunder by way of example. In the figures:
The turnout 1, which is schematically illustrated in a top view in
In front of and behind the turnout 1, the rails 4 are fastened in pairs so as to lie opposite one another in each case on one of the sleepers 5. Along the entire turnout 1, the sleepers 5 are disposed transversely, and in regions even orthogonally, to the respective longitudinal direction, cf. respective directions 11 and 12, of the main track 2 as well as of the branch track 3. The turnout 1 per se has the tongue rail device region 19, the closure track region 20 and the turnout frog region 10. Tongue rails 21, which are known per se and are pivotably disposed on tongue rail roots 18, which are known per se, are located in the tongue rail device region 19. Located within the turnout frog region 10 of the turnout 1, in the region denoted by A, are the turnout frog tip 9 and adjacent thereto the turnout frog gap 22, as is illustrated in an enlargement in
Adjoining the turnout frog region 10, a plurality of so-called short sleepers 25 follow on one side in the region of the main track 2 as well as in the region of the branch track 3, which short sleepers 25 may be of a design shortened on one side in comparison to the other sleepers 5 used in the main track 2 and in the branch track 3, due to the given space situation.
In the turnout frog region 10 per se, the sleepers 5 are designed as inherently continuous sleepers 5 on which the rails 4 of the main track 2 as well as the rails 4 of the branch track 3 are fastened. It is to be pointed out here, without being limited to a single exemplary embodiment, that continuous sleepers 5 can in each case be designed as an integral, inherently continuous member. However, a continuous sleeper 5 can also be formed from two or more sub-members when the latter are fixedly connected to one another so as to form the continuous sleeper in this way.
When the rail vehicles travel over this turnout frog gap 22, the wheels impact on the rails 4, or the turnout frog tip 9, as a result of which audible as well as perceptible impact noise is generated. All the more impact noise is created the more worn the wheels of the rail vehicles, or the more worn the track system per se is. In order to counteract this generation of audible as well as perceptible impact noise, it is provided in turnouts 1 according to the invention, as in the case of the turnout 1 illustrated here, that the respective elastomer layers 8 of the respective sleeper pads 7 of the sleepers 5 in the turnout frog region 10 are softer than the respective elastomer layers 8 of the respective sleeper pads 7 in regions of the turnout 1 in front of and behind the turnout frog region 10.
Reference is made to
The turnout frog region 10 extends so as to proceed from the turnout frog tip 9 in the mutually opposite directions 11 and 12, in each case at most over twenty-five successive sleepers 5. The number of sleepers 5 on the mutually opposite sides of the turnout frog tip 9 can be, but does not have to be, identical, as has already been explained. In preferred design embodiments, the turnout frog region 10 is of a smaller design. For example, it can extend in the mutually opposite directions 11 and 12 in each case at most over fifteen, preferably in each case at most over five, successive sleepers 5. This favourably applies to the main track 2 as well as to the branch track 3.
In the region in front of and behind the turnout frog region 10, the elastomer layers 8 of the respective sleeper pads 7 of the sleepers 5 are designed to be harder than in the turnout frog region 10. It is favourably provided that the elastomer layers 8 of the respective sleeper pads 7 outside the turnout frog region 10 at the respective measurement frequency have in each case a dynamic bedding modulus which is higher by at least a factor of 1.25, preferably by at least a factor of 2.0. In preferred design embodiments, the respective elastomer layers 8 of the respective sleeper pads 7 are composed of polyurethane and/or natural rubber. The sleeper pads 7 are in each case illustrated in a simplified manner in one piece in
The protective layer 14 serves to prevent ballast pebbles of the ballast bed 6 from ingressing too far into the elastomer layer 8, or destroying the latter. Forms of protective layers 14 which are known per se in the prior art and are also applicable in the context of the invention are, for example, geotextiles or other woven fabric layers. For the sake of completeness, it is however pointed out once again that the binding layer 13 as well as the protective layer 14 are optional. In turnouts 1 according to the invention, the sleeper pads 7 within the turnout frog region 10 as well as outside the latter have in each case at least one elastomer layer 8. In turnouts 1 according to the invention, the sleeper pads 7 can however also have more than one elastomer layer 8 within as well as outside the turnout frog region 10. Also in this case, the elastomer layers 8 are in any case softer in the region of the turnout frog region 10 than in front of and behind the latter.
As has already been explained at the outset, it is however also possible that the respective elastomer layers 8 of the respective sleeper pads 7 of the sleepers 5 in the turnout frog region 10 in the direction 15 of a longitudinal extent of the respective sleeper 5 have in each case a central region 16 and adjacent thereto two outer regions 17. This is shown by way of example by the section along the section line EE from
Here too, the dynamic bedding moduli of the elastomer layer 8 in the central region 16 as well as in the outer regions 17 are in the ranges already mentioned at the outset and in the claims.
In the outer regions 17, the elastomer layer 8 at 10 Hz however preferably has a dynamic bedding modulus in the range from 0.134 to 0.186 N/mm3, furthermore preferably from 0.139 to 0.181 N/mm3, and particularly preferably from 0.144 to 0.176 N/mm3. At 20 Hz, the dynamic bedding modulus in the regions 17 is preferably in the range from 0.28 to 0.42 N/mm3, furthermore preferably from 0.30 to 0.40 N/mm3, and particularly preferably from 0.32 to 0.39 N/mm3. At a measurement frequency of 160 Hz, the dynamic bedding modulus in the regions 17 is preferably in the range from 0.35 to 0.53 N/mm3, furthermore preferably from 0.37 to 0.51 N/mm3, and particularly preferably from 0.40 to 0.48 N/mm3.
In the softer, thus central, region 16, the elastomer layer 8 at 10 Hz has a dynamic bedding modulus preferably in the range from 0.088 to 0.145 N/mm3, furthermore preferably from 0.090 to 0.141 N/mm3, and particularly preferably from 0.095 to 0.138 N/mm3. At 20 Hz, the dynamic bedding modulus in this central region 16 is preferably in the range from 0.17 to 0.30 N/mm3, furthermore preferably from 0.18 to 0.29 N/mm3, and particularly preferably in the range from 0.19 to 0.28 N/mm3. At a measurement frequency of 160 Hz, the dynamic bedding modulus of the elastomer layer 8 in the region 16 is preferably in the range from 0.21 to 0.37 N/mm3, furthermore preferably from 0.22 to 0.36 N/mm3, and particularly preferably from 0.23 to 0.34 N/mm3.
These values of the dynamic bedding modulus at the various frequencies are also preferably determined according to DIN EN 16730:2016-09 according to the track category TC3.
| Number | Date | Country | Kind |
|---|---|---|---|
| A136/2023 | Nov 2023 | AT | national |
