Superstructure construction

Information

  • Patent Grant
  • 6409092
  • Patent Number
    6,409,092
  • Date Filed
    Monday, January 10, 2000
    24 years ago
  • Date Issued
    Tuesday, June 25, 2002
    22 years ago
Abstract
A superstructure arrangement for a track comprising a rail fastened to a securing device such as a ribbed plate which is disposed above a concrete sleeper, with an intermediate layer extending between the sleeper and the securing device. The rigidity of the intermediate layer is variable and rated so that at the maximum permissible stress in the rail, caused by bending under wheel lead, the elastic property changes to substantially non-elastic.
Description




BACKGROUND OF THE INVENTION




The invention relates to a superstructure construction comprising a rail disposed above a support layer such as a concrete sleeper and in its turn extending from a securing device such as a ribbed plate, where at least one intermediate layer with a rigidity x is disposed between the support layer and the securing device.




Bedding sleepers on ballast or resorting to designs with a ballastless track and stable, rigid sleeper mountings are known. In the latter case, the sleeper such as a concrete sleeper is placed on asphalt or concrete supporting plates or suitable troughs and then partially cast in place using a sealing compound such as concrete or asphalt.




To achieve a reduction of the structure-borne and airborne sound emitted by a rail in ballastless tracks, a construction is known where a standard rail such as S


54


is placed on a cork layer inside a channel comprising concrete or steel parts. In addition, cavities are provided that are filled at the top with a polyurethane/cork mixture to reduce sound.




However, this construction has not brought the desired result, and indeed sound measurements show that there has even been a 10 dB sound increase compared with the ballast construction.




A device for mounting rails for rolling stock is known from DE 89 15 837 U1, in which a ribbed plate is disposed on an elastic intermediate layer whose thickness is at least that of the ribbed plate. The intermediate layer can here have a required elasticity thanks to certain geometrical parameters. The same applies for DE 40 11 013 A1, which relates to a tempered rail structure for high-speed tracks. It is intended here to ensure, by providing a cavity with plastic-modified adhesive mortar, that a direct transmission of heat energy or cooling energy to the rail is prevented.




According to DE 41 38 575 A1, the spring rigidity of an elastic intermediate layer can be designed dependent on the contact force.









EP 0 632 164 A1 contains the proposal to structure the bottom of an elastic intermediate layer such that under load a higher rigidity results, while the transmission of sound is to be restricted at the same time.




An elastic rail support layer with bottom compression points and all-round closed edge strip is known from DE 43 14 578 A1.




The problem underlying the present invention is to develop a superstructure construction, in particular one on a ballastless track, such that a reduction of structure-borne and airborne sound is achieved.




The problem is substantially solved in accordance with the invention in that the rigidity x of the intermediate layer is rated such that at the maximum permissible and/or presettable rail stress in the rail the intermediate layer has substantially non-elastic properties such that further bending of the rail only takes place insubstantially if at all.




In accordance with the invention, the intermediate layer is rated for the permissible or required maximum rail stress, which has the advantage that the rail itself is on a softer support, thus achieving a decoupling between the rail and the sleeper. The effect of this is a lower loading of the support point and in turn a reduction in the structure-borne sound. This can be improved by using as rails those with high moment of inertia and moment of resistance when seen over the rail central axis, for example a filled section rail, so that the rail can perform the function of a support and develop a load-bearing effect. This results in a further decoupling between rail and sleeper, whereby a further reduction is achieved of the structure-borne sound emitted by the rail when it is traversed by rolling stock.




An intermediate layer is proposed that has a low rigidity before the maximum permissible and/or presettable rail stress is reached and a high rigidity when this rail stress is reached.




It is preferably provided here that the intermediate layer has a rigidity x of x≦25 kN/mm, preferably 4≦×≦25 kN/mm, and/or that at the maximum permissible rail stress the intermediate layer has a rigidity x of x≧35 kN/mm, in particular x≧90 kN/mm, preferably in the vicinity of 100 kN/mm.




SUMMARY OF THE INVENTION




In accordance with the invention, it is proposed that when the intermediate layer is without load it has projections extending beyond its underside and is surrounded within the intermediate layer by a cavity (recess) on the circumferential side. The cavity has a volume V


a


, which is equal to a volume V


b


that the respective projection has in its section projecting beyond the underside.




Thanks to the structure in accordance with the invention, the projections have the function of a supporting spring which is effective when the maximum rail stress of the rail supported by the support layer has not yet been reached. If this is then reached, the projections are forced into the support layer such that the projections are flush with the underside of the intermediate layer and at the same time fill the entire cavities (recesses). As a result, the form factor of the intermediate layer is increased such that the maximum permissible rail stress is not generally exceeded even when further forces are introduced. The intermediate layer should have a rigidity x which is in the vicinity of 100 kN/mm in particular when the cavities in the support layer are completely filled by the material of the projections.




It is provided in particular that the rail is a Vignol rail with a maximum permissible rail stress of 70 to 100 N/mm


2


and that the intermediate layer has a rigidity x of approximately 4 to 16 kN/mm, provided the maximum permissible rail stress has not yet been reached.




Apart from the geometry of the rail, an embodiment of the invention provides that in particular rails are used that have a moment of inertia I


x


with preferably I


x


≧3400 cm


4


and a moment of resistance W


x


with preferably W


x


≧350 cm


3


.




In particular, a superstructure construction with ballastless track is provided in which the rail is a filled section rail with a moment of inertia I


x


of 3700≦I


x


≦3800 cm


4


and a moment of resistance W


x


of 390≦W


x


≦410 cm


3


and a maximum required rail stress σ can be generated (approx. 70±4 N/mm


2


for rail steel UIC Class A with 880 N/mm


2


tensile strength) and the intermediate layer has a rigidity x of approximately 10±2 kN/mm for filled section tracks. In the case of traffic carriers with low axle loads, rigidities lower than the previously stated value are obtained.




In an embodiment of the invention, the arrangement provides for the rail to be designed at its foot such that the latter emits sound waves with a frequency v when vibrations are excited, said waves being substantially outside a frequency range between 500 and 3000 Hz. This results in a rail foot design in respect of its vibration technology that ensures a considerable reduction of the airborne sound.




In addition, the rail can be designed without a web, which also prevents problems from unwelcome airborne sound.




If the rail has a web, the latter should be designed such that it emits sound waves with a frequency v when vibrations are excited, said waves being substantially outside a frequency range between approximately 500 and 3000 Hz.




To ensure that the rail cannot tilt due to the fact that it rests on a relatively soft intermediate layer with its securing device, an embodiment of the invention provides that the rail forms together with the securing device such as a ribbed plate a unit which has the effect of widening the rail. The securing device here can be positioned inside the intermediate layer and enclosed by the latter along its longitudinal edge.




Further details, advantages and features of the invention are shown not only in the claims and in the features they contain—singly and/or in combination—but also in the following description of preferred design examples shown in the drawing.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

a section through a superstructure construction with a first embodiment of a Vignol rail,





FIG. 2

a section through a superstructure construction with a second embodiment of a Vignol rail,





FIG. 3

a section through a superstructure construction with a filled section rail,





FIG. 4

a section through an intermediate layer with low effective rigidity,





FIG. 5

the intermediate layer according to

FIG. 4

with high effective rigidity, and,





FIG. 6

a characteristic.











DETAILED DESCRIPTION OF THE INVENTION




The figures—where as a general rule identical elements are identified by identical reference numbers—show sections through a ballastless track comprising a concrete sleeper


10


, a ribbed plate


16


connected thereto by bolts


12


,


14


, and a rail attached to this ribbed plate, the rails being a UIC


60


rail


18


in

FIG. 1

, a Vignol rail


20


in

FIG. 2

, which has a changed vibration technology compared with the UIC


60


rail


18


in respect of the web


22


and the foot


24


, and a filled section rail


26


in FIG.


3


.




The respective rails


18


,


20


,


26


are secured to the ribbed plate


16


using suitable fasteners such as clips


28


,


30


resting on the feet


24


or


32


,


34


of the rails


20


or


18


and


26


respectively. Here the connection between the fasteners


28


and


30


and the respective rail feet


24


,


32


,


34


is such that a mechanical unit is formed that leads to an apparent widening of the rail foot. As a result, the respective rail


18


,


20


,


26


attains a greater tilting stability.




As regards the fastening of the ribbed plate


16


to the concrete sleeper


10


using the bolts


12


and


14


, reference is made to standard designs, in particular however to those found in WO 95/17552.




Regardless of the type of fastening between the ribbed plate


16


or element with the same effect and the sleeper


10


, however, it is provided in accordance with the invention that an elastic intermediate layer


36


,


38


,


40


passes between the ribbed plate


16


or corresponding securing device for the rail


18


,


20


,


26


respectively and the sleeper


10


, said intermediate layer having a rigidity x that depends on the maximum required rail stress of the respective rail


18


,


20


,


26


. In this case the ribbed plate


16


is preferably vulcanized into the intermediate layer


36


,


38


,


40


, which in turn has a so-called kinked rigidity characteristic. This means that the intermediate layer


36


,


38


,


40


has properties which are soft in that working range in which the rail


18


,


20


,


26


has not yet reached the maximum permissible rail stress, but then abruptly become hard when the maximum permissible rail stress prevails. To obtain a so-called kinked characteristic, design measures to be found in WO 94/08093 can be selected.




In particular however, the measures to be found in

FIGS. 4 and 5

must be provided, in order to set the rigidity of the intermediate layer such that its properties are soft before the maximum permissible rail stress is reached, and then change abruptly to hard properties when the maximum permissible rail stress prevails.




An intermediate layer


36


,


38


,


40


shown in

FIGS. 1

to


3


can in its principle have a design as shown in

FIGS. 4 and 5

and provided with the reference number


42


. The intermediate layer


42


therefore has projections


46


projecting beyond its underside


44


. At the same time, the projections


46


are surrounded by a cavity


48


(recess in the intermediate layer


42


) when the intermediate layer


42


is without load. This cavity


48


has a volume V


u


corresponding to the volume V


b


of that section


50


of the projections


46


which extends beyond the underside


44


of the intermediate layer


42


.




The projections


46


perform, under standard loading of the rail, i.e. before the maximum permissible rail stress is attained, supporting spring functions, and accordingly support the ribbed plate


16


alone. As the force introduced increases and, concomitantly, the rail stress likewise increases, the projection


46


is forced more and more into the intermediate layer


42


, the result being that the cavity


48


is filled by the material of the projection


46


. When the maximum permissible rail stress is reached, the projection


46


fills the entire cavity


48


, so that as a consequence thereof the front face


52


of the projection


46


is flush with the underside


44


of the intermediate layer


42


. Because of this, the entire intermediate layer


42


performs supporting functions, with the result that the intermediate layer as a whole is effective with a high rigidity. This in turn means that when further forces are introduced into the rail its rail stress can only be increased insubstantially, if at all.





FIG. 5

shows the intermediate layer


42


with the projections


46


forced into it. It can be seen that the front faces


52


of the projections are aligned with the underside


44


of the intermediate layer


42


.





FIG. 6

shows purely in principle the characteristic of the intermediate layer


42


. The subsidence s is therefore shown as a function of the force acting on the intermediate layer


42


. In the area in which the maximum permissible rail stress has not yet been reached the characteristic has a flat curve, which rises steeply when the maximum permissible rail stress has been reached.




In other words, the intermediate layer


42


is designed such that the rail is bendable enough that the maximum permissible rail stress can be generated and when the latter is reached no further bending is possible, since the intermediate layer


42


has a high rigidity x which is preferably in the vicinity of 100 kN/mm or more.




The maximum permissible rail stress is that rail stress which can occur at the foot underside and can be ascertained using a measuring strip, for example. It is provided here for ballastless tracks that the maximum required rail stress is 70±4 N/mm


2


with a standard wheel load of 10 t in rolling stock traversing the rail.




To permit an appropriate maximum rail stress when rolling stock with a wheel load of 10 t traverses the rail, the rigidity x of the respective intermediate layer


36


,


38


,


40


is rated accordingly, i.e. the rigidity x of the intermediate layer


36


,


38


,


40


compared with known superstructure constructions is reduced, meaning that the rail


18


,


20


,


26


can have a softer support. This in turn results in a reduction of the structure-borne sound since the rail


18


,


20


,


26


is decoupled from the sleeper


10


. The support point load is reduced too.




To realize the teachings in accordance with the invention, however, it is provided that the intermediate layer


36


,


38


,


40


has in respect of its spring properties or rigidity a so-called kinked characteristic. The intermediate layer


36


,


38


,


40


therefore has elastic or “soft” properties as long as the maximum permissible or presettable rail stress has not yet been reached. If this rail stress does prevail, the intermediate layer


36


,


38


,


40


is “hard”, i.e. has a high rigidity, so that there is no further bending of the rail


18


,


20


,


26


and hence no increase in the rail stress.




Since a rail can, depending on its geometry, more or less perform the function of a support and hence develop a load-carrying effect, a reduction of the rigidity x of the intermediate layer results when the moment of inertia I


x


and the moment of resistance W


x


of the rail are increased, i.e. for example when the geometry of a standard UIC


60


rail


18


is altered to the effect that the web


22


is widened and the rail foot


24


merges with a slight curvature into the web


22


in accordance with FIG.


2


. The result of this is that the rail


20


can be mounted more softly without exceeding the maximum permissible rail stress of 70±4 N/mm


2


in particular. Soft mounting means however a further decoupling from the sleeper


10


, with the consequence that the structure-borne sound emitted by the rail


20


is reduced.




Even better results are obtained with the filled section rail


26


according to

FIG. 3

, since the even higher moment of inertia I


x


and moment of resistance W


x


permit an even softer mounting before the maximum permissible rail stress is attained.




The geometry of the rail


20


or that of the filled section rail


26


furthermore has the advantage that the foot


24


or


34


respectively has been changed in its vibration technology compared with the UIC


60


rail


18


, such that when vibrations are excited the emitted sound is not in the undesirable frequency range between 500 and 3000 Hz. The widening or shape alteration of the web


22


of the rail


20


also reduces the airborne sound usually emitted by the web of a Vignol rail.




On the basis of the teachings in accordance with the invention, that the rail


18


,


20


,


26


is elastically mounted on the intermediate layer


36


,


38


,


40


such that under normal wheel loads the maximum permissible rail stress can be reached, but—thanks to the kinked curve of the characteristic—is not generally exceeded, the advantage is obtained that the rail


18


,


20


,


26


and the sleeper


10


are decoupled such that undesirable structure-borne sound is prevented. If in addition a filled section rail


26


or a Vignol rail


20


with web


22


of modified vibration characteristics and foot


24


is used in order to largely suppress the emission of airborne sound in the range between 500 and 3000 Hz, the result is an improvement of the ballastless track from the acoustic viewpoint.




Taking into account the teachings in accordance with the invention, the result for a filled section rail Vo 1-60 with I


x


=3760 cm


4


, W


x


=430 cm


3


and a maximum permissible rail stress of 73 N/mm


2


for the intermediate layer


40


is a rigidity of 10 kN/mm, from which in turn a maximum support point load of 25.3 kN is calculated. These values apply in that working range in which the maximum rail stress is not exceeded. If by contrast the latter is reached, the rigidity of the intermediate layer


40


changes such that the latter is “hard”, i.e. largely non-elastic, so that there is no further bending of the rail. In this “hard” range the rigidity x should be ≧35 kN/mm.




These values show that the filled section rail


26


is decoupled from the support layer


40


to an extent that when it is traversed by rolling stock the structure-borne sound of the rail


26


is only transmitted to a minor extent to the sleeper


10


and hence to the substructure.



Claims
  • 1. A superstructure arrangement for a track comprising:a rail (18, 20, 26) fastened to a securing device (16) which is disposed above a sleeper (10) and at least one intermediate layer (36, 38, 40) extending between the sleeper and the securing device, the rail having a maximum permissible stress; wherein the intermediate layer has a rigidity x such that at the maximum permissible stress in the rail by bending generated in response to wheel load, the intermediate layer has a substantially non-elastic property, so that further bending of the rail under additional load causes only insubstantial additional stress in said rail.
  • 2. The superstructure arrangement according to claim 1, wherein the intermediate layer has a rigidity x of x≦25 kN/mm.
  • 3. The superstructure arrangement according to claim 1, wherein at the maximum permissible rail stress, the intermediate layer has a rigidity x of x≧35 kN/mm.
  • 4. The superstructure arrangement according to claim 1, wherein the rail is a Vignol rail (20) with a maximum permissible rail stress of 70 to 100 N/mm2 and wherein the intermediate layer (38) has a rigidity x of 4 to 16 kN/mm before the maximum permissible rail stress is reached.
  • 5. The superstructure arrangement according to claim 1, wherein the rail is a filled section rail (26), comprising with approximately 880 N/mm2 tensile strength with a moment of inertia Ix of Ix≧3700 cm4 and/or a moment of resistance Wx of Wx≧390 cm3, and wherein at a maximum required rail stress of 70±4 N/mm2, the intermediate layer (40) has a rigidity x of 10±2 kN/mm.
  • 6. The superstructure arrangement according to claim 1, wherein the foot of the rail (20) emits sound waves with a frequency v when vibrations are excited, said waves being substantially outside a frequency range between 500 and 3000 Hz.
  • 7. The superstructure arrangement according to claim 1, wherein the rail (26) is designed without a web.
  • 8. The superstructure arrangement according to claim 1, wherein the rail (20) is designed at its web such that the web (22) emits sound waves with a frequency v when vibrations are excited, said waves being substantially outside a frequency range between 500 and 3000 Hz.
  • 9. The superstructure arrangement according to claim 1, wherein the rail (18, 20, 26) forms with the securing device (16) a unit effecting a widening of a rail foot.
  • 10. The superstructure arrangement according to claim 1, wherein the intermediate layer is positioned inside the securing device and enclosed by said securing device.
  • 11. The superstructure arrangement according to claim 1, wherein the rigidity x of the intermediate layer is rated such that the rail is deformable up to a rail stress in the range from 70 to 100 N/mm2.
  • 12. The superstructure arrangement according to claim 1 wherein the intermediate layer has a rigidity x in the range of 4≦×≧25 kN/mm.
  • 13. The superstructure arrangement according to claim 1, wherein at the maximum permissible rail stress, the intermediate layer has a rigidity x such that x≧90 kN/mm.
  • 14. The superstructure arrangement according to claim 1, wherein at the maximum permissible rail stress, the intermediate layer has a rigidity x such that x is equal to about 100 kN/mm.
  • 15. The superstructure arrangement according to claim 1, wherein the rail is a filled section rail (26) with approximately 880 N/mm2 tensile strength with a moment of inertia Ix of Ix≧3700 cm4 and/or a moment of resistance Wx of Wx≧390 cm3, and wherein at a maximum required rail stress of 70±4 N/mm2, the intermediate layer (40) has a rigidity x of 10±2 kN/mm.
  • 16. A superstructure arrangement for a track comprising:a sleeper; a securing device fastened to said sleeper; a rail fastened to said securing device and having a maximum stress level; and an intermediate layer mounted between said securing device and said sleeper, said intermediate layer being elastic in response to forces up to a first amount and being rigid in response to forces greater than said first amount wherein said first amount is equal to about said maximum stress level.
  • 17. A superstructure arrangement for a track comprising:a sleeper; a securing device fastened to said sleeper; a rail fastened to said securing device and having a maximum stress level; and decoupling means mounted between said securing device and said sleeper for substantially decoupling said rail from said sleeper while substantially preventing stress in said rail from exceeding said maximum stress level.
Priority Claims (2)
Number Date Country Kind
195 39 144 Oct 1995 DE
195 44 055 Nov 1995 DE
Parent Case Info

The present application is a continuation of application Ser. No. 09/051,476 filed Aug. 11, 1998, now U.S. Pat. No. 6,027,034, which is a 371 PCT/EP96/04536 filed Oct. 18, 1996.

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4771944 Brister et al. Sep 1988 A
4775103 Ortwein Oct 1988 A
5165598 Ortwein Nov 1992 A
5195679 Leeves et al. Mar 1993 A
5335850 Igwemezie Aug 1994 A
5361986 Meier et al. Nov 1994 A
5645216 Benenowski et al. Jul 1997 A
6027034 Demmig et al. Feb 2000 A
Foreign Referenced Citations (6)
Number Date Country
4011013 Jun 1991 DE
89158377 Oct 1991 DE
4138575 May 1993 DE
4314578 Nov 1994 DE
0632164 Jan 1995 EP
9506165 Mar 1995 WO
Continuations (1)
Number Date Country
Parent 09/051476 US
Child 09/479932 US