Swinging railway sleeper

Abstract

The subject of the present invention is a swinging railway sleeper comprising a base (5) seated immovably relative to a subgrade (6), and comprising a sleeper swinging portion (7) to which rail stretches (TS) are mounted, which is slidingly movable on sliding surfaces (8 and 9) in a longitudinal direction (KP) relative to the base (5), and thus in a transverse direction relative to a track direction KT, with a constant gauge (W) of the rails in the rail stretches (TS).

Description

[0001] Swinging railway sleeper

[0002] The subject-matter of the present invention is a swinging railway sleeper, in particular for railway applications.

[0003] The railway sleepers used in the prior art, utilized to transfer loads from the rails towards the subgrade, and the requirements in relation to them are described in the PN-EN 13145 standards and the standard series PN-EN 13230, as well as in the manual Id-101 PKP Polskie Linie Koi ej owe SA. - Warunki techniczne wykonania i odbioru podkladow i podrozjazdnic strunobetonowych, PKP Polskie Linie Kolejowe S.A. Warsaw, 2010.

[0004] From the document EP0412022 an invention is also known relating to a railway sleeper comprising a pair of hollow thrust blocks connected together by means of a connecting tie rod, wherein each thrust block is provided in order to support a rail of the said railway line. The sleeper according to the present invention is distinguished by the said rod being attached with at least one end to the respective thrust brick by means of a hinge situated inside the said thrust brick, wherein the hinge is formed in particular by a fixed or integral thrust brick spindle, substantially perpendicularly to the rod, and by a sleeve which is situated at a respective end of the said rod and which is intended to be slided through the said spindle around which it can rotate.

[0005] A railway sleeper is known from the description of the document EP 1897992 with a sleeper body which at its opposite ends has a rail support area in which the sleeper body is widened, wherein in each rail support area a rail can be mounted by means of a retaining element embracing a rail foot, and wherein each rail support area possesses three rail support surfaces lying next to each other along the rail, characterized in that at least one retaining element is arranged between and above at least one partial area of the adjacent rail support surfaces of each rail support area.

[0006] The solutions to date presenting the railway sleepers possess a common feature which is an inability of the sleeper to displace itself in a transverse direction to the track axis. This problem is significant in that the said inability of the sleeper to displace itself in the transverse direction to the track axis (especially in a circular arc with a small radius) renders impossible a controlled transformation of the longitudinal forces arisen in the rails (as a result of thermal stresses) into transverse forces. This technical problem is solved by the present invention by providing an swinging track sleeper that is improved and drawback-free with respect to the solutions known to date.

[0007] The object of the present invention is to supply an improved track sleeper which will eliminate the inconveniences associated with the lack of displacement of the sleeper in the transverse direction to the track axis. As per the idea of the present invention, the swinging railway sleeper is characterized in that it enables a rail stretch to displace itself in a transverse direction to the track axis. The said displacement of the rail stretch allows for a transformation of the longitudinal forces (arising in the railway rails and originating from the thermal expansion of these rails) into transverse forces to a track direction, which will enable to increase the resistance of the rails to thermal expansion.

[0008] The essence of the present invention is a swinging railway sleeper comprising a base seated immovably relative to the subgrade and rail stretches attached to the sleeper in which a swinging portion is mounted on the base which is slidingly movable on sliding surfaces in a longitudinal direction relative to the base and in a transverse direction relative to a track direction, with a constant gauge of the rails in the rail stretches.

[0009] Preferably, a layer of grease is arranged between the sliding surface of the base and the sliding surface of the swinging portion.

[0010] Preferably, the sliding surface of the base has a shape corresponding to the sliding surface of the swinging portion.

[0011] Preferably, the sliding surface of the swinging portion is shaped in a stepped manner. It can also be V-shaped or inverted V-shaped.

[0012] An advantage of the present invention with respect to the prior art is that the swinging railway sleeper has its application in a contactless track system with an increased resistance to thermal expansion of the rails. By using the present invention, it is also enabled to make a contactless track with a radius smaller than 300 m. Up to this time, the contactless track structure was used in circular arcs of above 300 m because of the possibility of a track buckling caused by the thermal stresses of the rails occurring on such a small curvature. The use of the present invention will allow this structure to be employed in arcs with radii smaller than 300 m, enabling to compensate the thermal longitudinal displacement occurring in the rail stretches through the use of a swinging sleeper which will transform the longitudinal displacement of the rails into their transverse displacement relative to the track axis. Embodiments according to the present invention are shown in the drawing, in which:

[0013] - Fig. 1 - shows, in a perspective projection, a swinging railway sleeper.

[0014] The subject of the present invention is a swinging railway sleeper shown according to the embodiment of Fig. 1, the structure of which enables both rail stretches TS installed on it to be displaced in a transverse direction KP to a track direction KT, without a change of gauge W of the rails in the rail stretches TS. The swinging railway sleeper comprises a base 5 seated immovably relative to a subgrade 6, a swinging portion 7 slidingly movable on sliding surfaces 8 and 9 in a longitudinal direction KP relative to the base 5, and thus in the transverse direction relative to the track direction KT.

[0015] The base 5 is a suitably profiled beam with an appropriate rigidity, made from, e.g., pretensioned prestressed concrete, other composite materials, metal or wood.

[0016] The subgrade 6 is an ground construction transferring pressures from the railway rolling stock situated on the track onto the native or embankment soil. In a particular case, the base 1 may be seated immovably relative to the subgrade 2 through the employment of a railway ballast.

[0017] The swinging portion 7 is a suitably profiled beam with an appropriate rigidity, made from, e.g., pre-tensioned prestressed concrete, other composite materials, metal or wood. It is preferable to make the swinging portion 7 and the base 5 of pre-tensioned prestressed concrete with steel fittings embedded in it that form the sliding surfaces 8 on the base 5 and the counterparts of these sliding surfaces 9 on the swinging portion 7. Then, for lubricating the adjacent sliding surfaces at the interface of the base 5 and the swinging portion 7, e.g., an agent for lubricating friction parts in railway turnouts, named PAMIR 1100 - a grease approved by PKP PLK S.A. may be used.

[0018] The sliding surfaces 8 and 9 are planes made from a suitably abrasion-resistant material (e.g. metal) in the base 5 and in the swinging portion 7. The operation of the system is favorably influenced by the use of a friction-reducing grease between the sliding surfaces 8 and 9. The shape of the sliding surfaces, shown in Fig. 3, (or rather their mutual position) renders impossible a displacement of the swinging portion 7 relative to the base 5 in the direction KT, longitudinal to the track axis. List of reference signs

[0019] 5 - sleeper base

[0020] 6 - subgrade

[0021] TS - rail stretches 7 - sleeper swinging portion

[0022] 8 - sliding surfaces in the sleeper base

[0023] 9 - sliding surfaces in the sleeper swinging portion

[0024] KP - movement direction of the sleeper swinging portion on the sleeper base

[0025] KT - movement direction of trains, identical to the track direction, transverse to the direction KP

[0026] W - constant gauge of the tracks in the rail stretches

Claims

Claims1. A swinging railway sleeper comprising a base (5) seated immovably relative to a subgrade (6), and comprising a sleeper swinging portion (7) to which rail stretches (TS) are mounted, characterized in that the swinging portion (7) is seated on the base (5) which is slidingly movable on sliding surfaces (8 and 9) in a longitudinal direction (KP) relative to the base (5), and thus in a transverse direction relative to a track direction KT, with a constant gauge (W) of the rails in the rail stretches (TS).

2. The sleeper according to claim 1, characterized in that a layer of grease is arranged between the sliding surface (8) of the base (5) and the sliding surface (9) of the swinging portion (7).

3. The sleeper according to claim 1 or 2, characterized in that the sliding surface (8) of the base (5) has a shape corresponding to the sliding surface (9) of the swinging portion (7).

4. The sleeper according to claim 3, characterized in that the sliding surfaces (8) and (9) are shaped in a stepped manner or are V-shaped or inverted V-shaped.

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