One-piece tie having recesses

Abstract

The invention relates to a one-piece concrete railroad tie (10A, 10B, 10C) intended to be anchored in the ballast and to support railroad rails (52), the tie (10A, 10B, 10C) comprising a central portion (12) and two rail support portions (14) positioned on either side of the central portion (12), each of the two rail support portions (14) comprising at least one recess (16a, b), the recess being formed by a lateral flank (18a, b) of the rail support (14) and by three walls (20a, b, 22a, b, 24a, b) emerging from the lateral flank (18a, b), and being configured to be able to receive ballast grains when the tie (10A, 10B, 10C) is in a functional position on the ballast of the railroad.

Description

[0001] SINGLE-PIECE CROSS-MEMBER WITH RECESSES

[0002] DESCRIPTION

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to a single-piece concrete railway sleeper intended to be anchored in ballast and to support railway rails. The invention also relates to a railway track comprising such a sleeper.

[0005] TECHNOLOGICAL BACKGROUND

[0006] Railway tracks are usually formed by two rails along which trains travel. The rails are attached to sleepers that run perpendicular to the rails and are anchored in a bed of ballast. The ballast is made up of a multitude of pebbles, also called ballast grains.

[0007] When trains travel over railway tracks, they generate a lot of vibrations and exert significant forces on the rails, particularly lateral forces on curves. The function of sleepers is to keep the rails parallel to each other and also to keep the sleeper / rail assembly firmly anchored in the ballast in a fixed position and with good stability, despite the vibrations and forces exerted on the rails. For trains traveling at high speed, the sleeper / rail assembly is subjected to even greater vibrations and forces.

[0008] Sleepers can be made of different materials such as wood, concrete or more recently polymer or composite materials. However, wood, polymer materials and composite materials are not heavy and / or strong enough to be used for railway tracks on which high-speed trains run and / or tracks with long welded rails. Indeed, because sleepers are light, they are not sufficiently anchored in the ballast to ensure good stability of the sleeper / rail assembly. Concrete sleepers with a high density, particularly between 2 and 2.5, and good strength are therefore preferred, particularly for railway tracks on which high-speed trains run and / or tracks with long welded rails.

[0009] In order to further improve the anchoring of the concrete sleepers in the ballast as well as their stability, sleepers comprising reliefs on their lower face, intended to be in contact with the ballast, have been developed. Such sleepers shown in Figure 1, comprise a central portion 2, two end portions 3 and two rail support portions 4 each positioned between the central portion 2 and one of the end portions 3. The support portions 4 each comprise a rail attachment device 5 and are widened relative to the rest of the sleeper 1 because it is at the level of the rails that the forces, in particular lateral forces, exerted by the train, are the greatest.

[0010] The sleeper 1 also has a lower face 6 comprising an alternation of grooves 7 and ribs 7' extending in a transverse direction relative to the sleeper and making it possible to improve the anchoring of the sleeper 1 in the ballast and therefore its stability.

[0011] However, the manufacture of concrete sleepers involves the consumption of natural resources such as water, gravel, sand and cement constituents (clay and limestone) and therefore results in a significant carbon footprint. For example, a sleeper meeting the standard gauge used by SNCF has a length of 2260 mm and a trapezoidal section with a base of 300 mm and a height of 170 mm. Such a standard sleeper weighs 290 kg and its manufacture typically generates a quantity of CO2 of 46 kg.

[0012] STATEMENT OF THE INVENTION

[0013] An objective of the invention is to reduce the quantity of materials used in the manufacture of the concrete sleeper while maintaining, or even improving, the stability of said sleeper in the functional position, and in particular its anchoring in the ballast.

[0014] Preferably, the concrete sleeper should have dimensions corresponding to standard sleepers so that it can be handled and installed using standard procedures.

[0015] To this end, the invention has as its first subject a single-piece concrete railway sleeper intended to be anchored in the ballast and to support railway rails, said sleeper comprising a central portion and two rail support portions positioned on either side of the central portion, each of the two rail support portions comprising at least one recess, said recess being formed by a lateral flank of the rail support portion and by three walls emerging from said lateral flank and being configured to be able to receive grains of ballast when the sleeper is in the operative position on the railway ballast, each rail support portion has a length 11 and the bottom wall extends over at least 80% of the length 11. The sleeper is thus firmly anchored in the ballast and is therefore more stable than sleepers of the prior art.Indeed, the ballast grains that are arranged in the recess make the sleeper heavier, making it less easy to move when trains pass by. In addition, contact points between the ballast grains and also between each ballast grain and the sleeper create friction forces that make it even more difficult to move the sleeper.

[0016] In addition, the presence of a recess makes it possible to reduce the quantity of concrete used for the manufacture of the sleeper, which therefore reduces the quantity of water and materials used to manufacture the sleeper, and also the quantity of CO2 emitted for said manufacture.

[0017] Advantageously, the recess is positioned at the support portion because this is the portion of the sleeper on which the railway rails rest when the latter is in its functional position and therefore the portion of the sleeper which is most likely to move when trains pass over it. Ballasting the sleeper using ballast grains and at this rail support portion thus optimizes the stability of the sleeper.

[0018] Furthermore, the length of the recess is optimized so as to make the sleeper heavier over a large part of the rail support portion, even under the rail. Preferably, the recess extends over the entire length of the rail support portion.

[0019] According to a preferred embodiment, each rail support portion has two recesses, one being provided against one flank of the support portion and the other being provided against an opposite flank of said support portion.

[0020] According to particular embodiments of the invention which can be taken alone or in combination:

[0021] - the three walls are connected to each other to form a “U”;

[0022] - at least one of the three walls of said at least one recess extends laterally over a distance L1 greater than or equal to 30 mm; thus the recess has a depth greater than half of a possible dimension of the ballast grains which can conventionally range from 31.5 to 50 mm, which makes it possible to guarantee that at least certain ballast grains have their center of gravity positioned in the recess and that their weight contributes to ballasting the sleeper by creating weight in the recess;

[0023] - the three walls are a bottom wall and two side walls, the bottom wall forming an angle with the side flank of the rail support portion of a value ranging from 95° to 150°, preferably ranging from 100° to 135°; the bottom wall thus has a sufficiently low inclination so that the ballast grains can remain in place in the recess but sufficient to reinforce the bottom wall and prevent it from breaking under the effect of the ballast grains or during handling of the latter; the central portion comprises two side flanks and at least one anchoring element emerges from each of the two side flanks, said at least one anchoring element extending in a direction perpendicular to the plane of the side flanks;the anchoring element(s) improve(s) the stability of the sleeper in the ballast grains, in particular due to the ballast grains which are positioned on either side of these anchoring elements when the sleeper is in the functional position;

[0024] - each anchoring element extends from the lateral flank of the central portion over a length L4 greater than or equal to 30 mm; thus the anchoring element has a length greater than a possible dimension of a ballast grain, which allows at least some ballast grains to be largely positioned between the lateral flank of the central portion and a free end of the anchoring element so as to stabilize the sleeper in an optimized manner; one of the side walls is an internal wall positioned between the lateral flank of the rail support portion and the lateral flank of the central portion and a housing is formed between said at least one anchoring element and the internal wall, said housing being configured to accommodate ballast grains; the housing thus makes it possible to stabilize the sleeper by accommodating ballast grains without weighing down the sleeper;preferably, the crosspiece does not have a bottom wall between the internal wall and the anchoring element; preferably, the internal wall and the anchoring element emerge from the lateral flank of the central portion by a distance of at least 30 mm;

[0025] - said at least one anchoring element emerging from a lateral flank and said at least one anchoring element emerging from the opposite lateral flank are aligned two by two; the crosspiece is thus stabilized in the same way on each of its lateral flanks;

[0026] - the crosspiece has a density greater than or equal to 1.8; this density allows the crosspiece to be sufficiently heavy and therefore stable when it is in its functional position; and

[0027] - each support portion has a railway rail attachment device.

[0028] The second subject of the invention is a railway track comprising at least one sleeper according to the first subject.

[0029] The railway track is thus more stable than a railway track comprising only sleepers according to the prior art. Preferably, the railway track comprises a plurality of sleepers such as those previously described, and even more preferably, only sleepers such as previously described.

[0030] BRIEF DESCRIPTION OF THE FIGURES

[0031] Other characteristics and advantages of the invention will appear on reading the description which follows, given solely by way of example and made with reference to the appended drawings, in which:

[0032] - figure 1 represents a schematic and perspective view of a sleeper of the prior art; figure 2a represents a schematic and perspective view of a sleeper according to a first embodiment of the invention;

[0033] - figure 2b represents a schematic top view of the crosspiece of figure 2a;

[0034] - figure 2c represents a schematic side view of the crosspiece of figure 2a; figure 3a represents a schematic and perspective view of a crosspiece according to a second embodiment of the invention;

[0035] - figure 3b represents a schematic top view of the crosspiece of figure 3a;

[0036] - figure 3c represents a schematic side view of the crosspiece of figure 3a;

[0037] - figure 4 represents a schematic perspective view of a sleeper according to a variant of the second embodiment; figure 5 represents schematically in a top view a railway track according to an embodiment of the invention;

[0038] - figure 6 represents a schematic view of a crosspiece of the prior art;

[0039] - Figure 7 represents a schematic view of a sample of railway track according to an embodiment of the invention in ballast; and

[0040] - Figure 8 represents a graph illustrating the results of the test carried out on samples from Figure 7.

[0041] DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT With reference to Figures 2a to 2c, a railway sleeper 10A according to a first embodiment of the invention comprises a central portion 12 as well as two rail support portions 14 (or support portion) positioned on either side of the central portion 12. The support portions 14 are more particularly positioned at each of the ends of the sleeper 10.

[0042] The 10A sleeper is a single-piece concrete piece of elongated shape and substantially square cross-section. The density of the sleeper is at least 1.8, preferably at least 2, so that the sleeper is sufficiently heavy and stable when in the operational position and can thus be used for railway tracks on which high-speed trains run.

[0043] Each support portion 14a, b comprises two recesses 16a and 16b formed in each of the two side walls of the support portion 14. Each recess 16a, b is formed by a side flank 18a, b of the support portion 14 as well as by three walls 20a, b, 22a, b and 24a, b which emerge from the side flank 18a, b.

[0044] The sleeper 10A is intended to be anchored in a conventional manner in a ballast bed. When the sleeper 10A is in its operative position in the ballast, it rests on ballast grains and its side walls are surrounded by ballast grains. In this position, only an upper surface 26 emerges from the ballast grains.

[0045] In side view of the sleeper, the three walls are connected together to form a U, with the open end of the U facing the upper surface of the sleeper.

[0046] Furthermore, the sleeper 10A comprises two fastening devices 28 on which iron rails can be conventionally fixed. In particular, a fastening device is positioned on the upper surface 26 at each rail support portion 14.

[0047] Thus, when the sleeper 10A is in its functional position, that is to say anchored in a bed of ballast and with a rail fixed on each rail support portion 14, the recesses 16a, b are filled with ballast grains. The sleeper 10A is thus made heavier, in particular at the rail support portions 14a, b, which optimizes its anchoring in the ballast so that it remains in a stable position despite the passage of trains. Furthermore, the ballast grains positioned in the recesses are in contact with each other and are also in contact with the walls and side of the sleeper 10A. These contacts create friction forces which make it possible to increase the anchoring of the sleeper in the ballast and therefore its resistance to movements induced by the passage of trains.

[0048] In addition, the presence of a recess makes it possible to reduce the quantity of concrete used for the manufacture of the sleeper compared to a sleeper of equivalent dimensions whose recesses would be filled with concrete. The quantity of water and materials used to manufacture the 10A sleeper is thus reduced, as is the quantity of CO2 emitted for this manufacture.

[0049] Advantageously, the recess is positioned at the level of the support portion because it is the portion of the sleeper on which the railway rails rest when the latter is in its functional position and therefore the portion of the sleeper which is most likely to move during the passage of trains. Ballasting the sleeper, by means of ballast grains, at the level of this support portion, and even under the rails, thus makes it possible to optimize the stability of the sleeper.

[0050] Sometimes, in the remainder of the description of this first embodiment, only the elements of one of the side walls of the crosspiece 10A will be described (elements indexed “a”) but the description also applies to the other side wall which is identical (elements indexed “b”).

[0051] The wall 20a of the recess forms a bottom wall, the wall 22a is an outer side wall and the wall 24a is an inner side wall. In this embodiment, the three walls 20a, 22a and 24a extend laterally over a distance L1 greater than or equal to 30 mm. The recess 16a thus has a depth allowing a plurality of ballast grains to be positioned in such a way that almost all of their volume is in the recess 16a and thus exert pressure in a vertical direction towards the bottom wall 20a. The depth corresponds to the distance L1, that is to say the distance between the lateral flank 18a of the support portion 14 and a free edge 17a of the bottom wall 20a.

[0052] Furthermore, the recess 18a has a height He defined as being the vertical distance between the upper surface 26 of the crosspiece and an upper surface of the free edge 17a of the bottom wall 20a. The distance He of the recess 18a is also greater than or equal to 30 mm, and preferably between 120 and 200 mm.

[0053] According to a possible embodiment variant, only the bottom wall 20a extends over the distance L1 and the side walls extend obliquely from the upper surface 26 towards a free edge of the bottom wall.

[0054] The bottom wall 20a, in particular its upper surface, forms an angle with the lateral flank 18a having a value of 120°. Advantageously, the inclination of the bottom wall 20a is a compromise between an inclination sufficiently low so that the ballast grains can remain in place in the recess 18a and an inclination sufficient to reinforce the bottom wall and prevent it from breaking under the effect of the ballast grains or during handling of the latter. In particular, the crosspiece 10A has a lower surface 30 that is flat and parallel to the upper surface 26. Thus, the inclination of the bottom wall 20a allows the latter to be thicker in its part positioned against the lateral flank 18a than at its free edge 17a, which reinforces its solidity.

[0055] According to possible embodiments, the inclination of the bottom wall 20a can have a value ranging from 95° to 150°, preferably from 100° to 135°.

[0056] Each rail support portion 14a has a length 11 and the bottom wall, in particular the free edge 17a, b of the bottom wall 20a, extends over a length 12 at least equal to 80% of the length 11. The length of the recess is thus optimized so as to weigh down the sleeper over a large part of the rail support portion 14a which is the portion most subject to movement due to the passage of trains.

[0057] According to this embodiment, the central portion 12 has a first lateral flank 32a and a second lateral flank 32b which are smooth. These lateral flanks 32a and 32b are parallel to each other and spaced apart by a width L2 which is the width of the central portion 12. The width L2 of the central portion 12 is smaller than a width L3 of the support portions 14a, b. Thus, the internal lateral walls 24a and the lateral flank 32a, on the one hand, and the internal lateral walls 24b and the lateral flank 32b, on the other hand, form two housings which can accommodate ballast grains and reinforce the anchoring of the sleeper 10A in the ballast.

[0058] A second embodiment is described with reference to Figures 3a to 3c. In this second embodiment, the crosspiece 10B differs from the crosspiece of the first embodiment essentially by the addition of anchoring elements which are described below. The other characteristics of the crosspiece are identical to those described in the first embodiment.

[0059] In this second embodiment, the crosspiece 10B comprises two anchoring elements 40a which emerge from the first lateral flank 32a and two anchoring elements which emerge from the second lateral flank 32b. The anchoring elements 40a, b extend in a direction perpendicular to the plane of the lateral flanks 32a, b.

[0060] The anchoring elements 40a, b make it possible to further improve the stability of the sleeper 10B in the ballast, in particular thanks to the ballast grains which are positioned on either side of these anchoring elements when the sleeper 10B is in the functional position.

[0061] Sometimes, in the remainder of the description of this second embodiment, only the elements of one of the side walls of the crosspiece 10B will be described (elements indexed “a”) but the description also applies to the other side wall which is identical (elements indexed “b”).

[0062] The anchoring elements 40a, b make it possible in particular to form housings capable of receiving the ballast grains along each of the lateral sides 32a, b. Two housings 42a are formed between each anchoring element 40a and each internal lateral wall 24a and a third housing 44a is formed between the two anchoring elements.

[0063] The housings 42a, b and 44a, b make it possible to accommodate ballast grains and thus to increase the contact surface between the sleeper 10B and the ballast grains. Furthermore, the plurality of ballast grains positioned in the housings and making contacts with each other increases the resistance of the ballast on the sleeper 10B and therefore improves the stability of the sleeper.

[0064] Each anchoring element 40a, b emerges from the lateral flanks of the central portion by a distance L4 of at least 30 mm which is thus equivalent to or substantially less than the distance L1.

[0065] The sleeper 10A has an average height H which ranges from a maximum height Hm at the end of the sleeper to a minimum height in the middle of the sleeper and which is slightly less than the maximum height. The anchoring elements 40a, b extend over at least 80% of the height H of the sleeper 10A, said height being considered at the location where each anchoring element 40a, b is located. In this way, the contact surface between the anchoring elements 40a, b and the ballast grains positioned in the housings 42a, b and 44a, b is thus optimized.

[0066] The anchoring elements 40a, b have a triangular shape in top view (or in cross-section) and which extends over the entire height of the crosspiece 10B. However, the anchoring elements may have other shapes and be, for example, of square, rectangular or semi-circular section.

[0067] The crosspiece 10B is symmetrical on either side of a longitudinal axis. Thus, each anchoring element 40a of the first lateral flank 32a is aligned with an anchoring element 40b of the second lateral flank 32b. In other words, the anchoring elements of the two opposite lateral flanks 32a and 32b are aligned two by two along an axis perpendicular to the longitudinal axis of the crosspiece. The crosspiece 10B is thus stabilized identically on each of its lateral flanks.

[0068] The anchoring elements 40a are spaced apart by a distance D1 from the internal side wall 24a and the two anchoring elements 40a are spaced apart by a distance D2, the distance D2 being greater than the distance D1. The distances D1 and D2 are measured between the axes of vertical symmetry of the anchoring elements 40a and the internal side walls 24a.

[0069] According to possible embodiments, the distances D1 and D2 may be equal or the distance D1 may be greater than the distance D2. Furthermore, according to other possible embodiments, the crosspiece may comprise a single anchoring element on each of the lateral flanks 32a and 32b like the crosspiece 10C illustrated in FIG. 5, or comprise three or four anchoring elements on each of the lateral flanks 32a and 32b.

[0070] With reference to Figure 4, a crosspiece 10C according to a variant of the second embodiment may comprise a single anchoring element 40a, b positioned in the middle of the lateral flank 32a, b, the other elements of the crosspiece being identical to the crosspiece 10B.

[0071] With reference to Figure 5, a railway track 50 according to one embodiment comprises a plurality of sleepers 10B such as those described according to the first or second embodiment as well as two rails 52 fixed to the attachment devices 28 of each of the sleepers.

[0072] The railway track is thus more stable than a railway track comprising only sleepers according to the prior art and can allow high-speed trains to run.

[0073] EXAMPLES

[0074] Laboratory tests were carried out to assess the strength of the anchoring of the sleepers in ballast.

[0075] The tests were carried out on 10À-C sleepers according to the invention and on a TC sleeper of the prior art. All sleepers are made of concrete and have a density greater than 1.8. The dimensions of the different sleepers tested are detailed below.

[0076] - Crossing 10A

[0077] • Maximum height (Hm) = 200 mm

[0078] • Maximum length (Im) = 2260 mm

[0079] • Maximum width (L3) = 300 mm

[0080] • Length of the support portion (11) = 661 mm

[0081] • Length of recess 16a, b (12) = 497 mm

[0082] • Height of the recess (He) = 136 mm

[0083] • Depth of the recess (L1) = 63 mm

[0084] • Distance between two internal side walls 24a, b (13) = 972 mm

[0085] • Weight = 205 kg - Crossbar 10B

[0086] • Maximum height (Hm) = 200 mm

[0087] • Maximum length (Im) = 2260 mm

[0088] • Maximum width (L3) = 300 mm

[0089] • Length of the support portion (11) = 661 mm

[0090] • Length of recess 16a, b (12) = 497 mm

[0091] • Height of the recess (He) = 136 mm

[0092] • Depth of the recess (L1) = 63 mm

[0093] • Length of anchoring elements 40a, b (L4) = 53 mm

[0094] • Distance between two anchoring elements 40a, b (D2) = 481 mm

[0095] • Distance between two internal side walls 24a, b (13) = 972 mm

[0096] • Distance between a side wall 24a, b and an anchoring element 40a, b (D1) = 255 mm

[0097] • Weight = 220 kg

[0098] - Crosses 10C following:

[0099] • Maximum height (Hm) = 200 mm

[0100] • Maximum length (Im) = 2260 mm

[0101] • Maximum width (L3) = 300 mm

[0102] • Length of the support portion (11) = 661 mm

[0103] • Length of recess 16a, b (12) = 497 mm

[0104] • Height of the recess (He) = 136 mm

[0105] • Depth of the recess (L1) = 63 mm

[0106] • Length of anchoring elements 40a, b (L4) = 53 mm

[0107] • Distance between two internal side walls 24a, b (13) = 972 mm

[0108] • Distance between a side wall 24a, b and an anchoring element 40a, b (D1) = 486 mm

[0109] • Weight = 215 kg

[0110] - TC crossing

[0111] • Maximum height (Hm) = 200 mm

[0112] • Maximum length (Im) = 2260 mm

[0113] • Maximum width (L3) = 300 mm

[0114] • Weight = 290 kg

[0115] Test protocol: Referring to Figure 7, a ballast bed 60 with a volume of approximately 2.5 to 3 m 3 is formed in a 62 tank with a length of 4 m, a width of 1.5 m and a height of 0.4 m.

[0116] The sample 70 tested corresponds to two sleepers 10 spaced 600 mm apart and to which two rail portions 64 are fixed, each rail portion 64 having a length of 1250 mm. The sleepers 10 are anchored in the ballast so that the ballast surrounds the side walls of the sleepers and only the surface 26 of the sleeper emerges from the ballast. A layer of ballast 350 mm high is then present under the sleepers.

[0117] A force is then applied to one of the rails 64 by means of a hydraulic jack 68 in a horizontal direction perpendicular to the longitudinal axis of the rail 64. The force has a load increase of 6 kilonewton / minute or 6kN / min.

[0118] A device 66 is used to measure the displacement of the sample in the direction of the applied force. Several tests are carried out for each sample.

[0119] The graph in Figure 8 represents the average force applied to the different samples to move them by 2 mm and 4 mm, the unit kN / TB meaning kilonewton per concrete sleeper.

[0120] The graph in Figure 8 represents the values ​​obtained for four samples, the first comprising two TC sleepers (sample 70TC), the second comprising two 10À sleepers (sample 70À), the third comprising two 10B sleepers (sample 70B) and the fourth comprising two 10C sleepers (sample 70C).

[0121] It can be seen that the force to be applied for sample 70À is similar to that applied for sample 70TC, which means that the anchoring of these two samples is similar. Indeed, for samples 70TC and 70À, a force of 3.90 kN / TB and 3.75 kN / TB respectively must be applied for the sample to move 2 mm, and a force of 4.40 kN / TB and 4.20 kN / TB respectively must be applied for the sample to move 4 mm. The recesses for accommodating ballast grains therefore make it possible to compensate for the lightening of the sleeper since the anchoring of sample 70À comprising two sleepers of 205 kg is equivalent to the anchoring of sample 70TC comprising two sleepers of 290 kg.

[0122] These tests also show that the force to be applied for samples 70B and 70C with sleepers equipped with anchoring elements must be greater than for samples 70TC and 70À without anchoring elements. Indeed, for samples 70B and 70C, a force of 5.20 kN / TB and 5.10 kN / TB respectively must be applied for the sample to move 2 mm, and a force of 5.40 kN / TB must be applied for the sample to move 4 mm. The anchoring elements therefore make it possible to significantly improve anchoring while reducing the weight of the sleepers used, and therefore limiting the quantity of raw material used during manufacturing and the carbon footprint linked to manufacturing.

Claims

CLAIMS 1. A single-piece concrete railway sleeper (10A, 10B, 10C) intended to be anchored in the ballast and to support railway rails (52), said sleeper (10A, 10B, 10C) comprising a central portion (12) and two rail support portions (14) positioned on either side of the central portion (12), each of the two rail support portions (14) comprising at least one recess (16a, b), said recess being formed by a lateral flank (18a, b) of the rail support (14) and by three walls (20a, b, 22a, b, 24a, b) emerging from said lateral flank (18a, b) and being configured to accommodate grains of ballast when the sleeper (10A, 10B, 10C) is in an operative position on the railway ballast, wherein each rail support portion (14) has a length 11 and the bottom wall (20a, b) extends over at least 80% of the length 11.

2. Crosspiece (10A, 10B, 10C) according to claim 1, in which the three walls are connected to each other so as to form a “U”.

3. Crosspiece (10A, 10B, 10C) according to claim 1 or 2, wherein at least one of the three walls (20a, b, 22a, b, 24a, b) of said at least one recess (16a, b) extends laterally over a distance L1 greater than or equal to 30 mm.

4. Sleeper (10A, 10B, 10C) according to any one of claims 1 to 3, in which the three walls are a bottom wall (20a, b) and two side walls (22a, b, 24a, b), the bottom wall (20a, b) forming an angle with the lateral flank (18a, b) of the rail support portion (14) of a value ranging from 90° to 150°, preferably ranging from 100° to 135°.

5. Crosspiece (10A, 10B, 10C) according to any one of claims 1 to 4, in which the central portion (12) comprises two lateral flanks (32a, b) and in which at least one anchoring element (40a, b) emerges from each of the two lateral flanks (32a, b), said at least one anchoring element (40a, b) extending in a direction perpendicular to the plane of the lateral flanks (32a, b).

6. Crosspiece (10A, 10B, 10C) according to claim 5, in which each anchoring element (40a, b) extends from a lateral flank (32a, b) of the central portion (12) over a length L4 greater than or equal to 30 mm.

7. Sleeper (10A, 10B, 10C) according to claim 5 or 6, wherein one of the side walls is an inner wall (24a, b) positioned between the lateral flank (18a, b) of the rail support portion (14) and the lateral flank (32a, b) of the central portion (12) and in which a housing (42a, b) is formed between said at least one anchoring element (40a, b) and the inner wall (24a, b), said housing (42a, b) being configured to receive ballast grains.

8. Crosspiece (10A, 10B, 10C) according to any one of claims 5 to 7, wherein said at least one anchoring element (40a) emerging from a lateral flank (32a) and said at least one anchoring element (40b) emerging from the opposite lateral flank (32b) are aligned two by two.

9. Crosspiece (10A, 10B, 10C) according to any one of claims 1 to 8, having a density greater than or equal to 1.

8.

10. Railway track comprising at least one sleeper (10A, 10B, 10C) according to any one of claims 1 to 9.

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