Crawler track link for a support carriage of a machine for laying or renovating a railway line and articulated arrangement of such links

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates, in general, to the technical field of machines for laying or renovating a railway track.

[0002] The invention relates more specifically to a track link for a support trolley of a railway track laying or renovation machine, to an articulated assembly of at least two such links, to a track running gear for a support trolley of a railway track laying or renovation machine, comprising a track made up of such an articulated assembly and to a support trolley of a railway track laying or renovation machine equipped with at least one such track running gear. PREVIOUS STATE OF THE ART

[0003] Railway construction and network operators regularly need to build new tracks or renovate existing ones, which means replacing some of their components such as rails and sleepers, as well as fastening systems and other accessories. Much of this renewal need stems from track wear, but it can also involve replacing older models with newer ones to improve performance. Such track laying and renovation operations are carried out using a railway train comprising multiple specialized machines to perform the various specific tasks.

[0004] During these operations, the railway convoy is generally required to move on a section of track without rails, in particular directly on sleepers.

[0005] Tracked trolley solutions exist, with the trolleys configured to move along the section of track without rails during these track laying or renovation operations.

[0006] However, due to cost considerations and differing lifespans, rail renewal is increasingly out of sync with sleeper renewal. The issue of protecting sleepers used by tracked vehicles during these operations is therefore becoming increasingly important.

[0007] Solutions to this problem are known, such as the one disclosed in document DE202021001054, which proposes surrounding the track with a band of protective rubber material. However, such mechanisms are complex because they involve managing the separate movement of the track and the protective rubber band, and in practice, create a number of constraints during use that necessitate regular maintenance, for example, to protect these components from the external environment and prevent degradation of their operation.

[0008] Document DE 20 2014 104957 U1 describes another example of a track link according to the preamble of claim 1. DESCRIPTION OF THE INVENTION

[0009] The invention aims to remedy all or part of the drawbacks of the prior art by proposing in particular a solution to better protect sleepers, especially at the level of their chamfers, during rail laying or renewal operations while improving the train trolleys, both in terms of their simplicity and their reliability.

[0010] To this end, according to a first aspect of the invention, a track link for a support trolley of a railway track laying or renovation machine is proposed, comprising a one-piece metal part defining two parallel and spaced-apart articulation axes, the one-piece metal part having a central portion located between the two articulation axes and two opposite end portions on either side of the central portion, each of the end portions being associated with one of the two articulation axes, and comprising several parallel fingers separated in pairs by fingerless spaces and traversed by holes aligned along the associated articulation axis, the one-piece metal part comprising a rolling face located on one side of a reference geometric plane containing the two articulation axes and a face opposite to the rolling face located on the other side of the reference geometric plane,the opposite face being covered with a layer of elastomeric material covering the central portion and at least part of each of the fingers of the two end portions.

[0011] Thanks to this combination of features, a link is obtained that is protected on its face opposite its running face by a layer of elastomeric material, allowing it to withstand stresses by being in direct contact with the sleepers. Once assembled with a plurality of other similar links to form a track, a plurality of layers of elastomeric material can be obtained, positioned discontinuously. These layers of elastomeric material are specific to each link, but their overlap on the opposite face, covering the central portion and at least part of each of the fingers of the two end portions, ensures that the links of such a track rest on a section of track without rails, during which a layer of elastomeric material is always present.

[0012] In one embodiment, the elastomeric material layer completely covers a main portion of the opposite face delimited by the two articulation axes, and covers at least part of the fingers of the two end portions beyond the main portion. Such links, assembled together to form a track, ensure continuity of the elastomeric material by maximizing the contact surface.

[0013] In one embodiment, the main portion of the opposite face is flat. This promotes an optimized contact surface.

[0014] According to one embodiment, the layer of elastomeric material has a thickness greater than or equal to 6 mm, preferably greater than or equal to 10 mm, and / or less than or equal to 15 mm, preferably less than or equal to 12 mm.

[0015] According to one embodiment, the end of each of the fingers is rounded, the rounding of each of said fingers preferably being delimited by a rounded connecting surface making the junction between a surface of the rolling face and a surface of the opposite face.

[0016] According to one embodiment, the elastomeric material layer has curved portions, each covering a rounded portion of the end of each finger on the side of the face opposite the rolling face.

[0017] According to one embodiment, the layer of elastomeric material is continuous, and preferably has a constant thickness.

[0018] According to one embodiment, the elastomeric material constituting the layer comprises rubber, preferably is made of rubber.

[0019] According to one embodiment, the elastomer material layer has a hardness greater than or equal to 92 Shore A, and / or less than or equal to 97 Shore A. Such hardness allows for improved resistance for use in the railway field.

[0020] According to one embodiment, the center distance between the hinge axes of the end portions is greater than or equal to 45 mm and / or less than or equal to 55 mm. This center distance allows the size of the links to be sufficiently reduced to improve the contact area on the sleepers of the railway track being laid or renovated.

[0021] According to one embodiment, at least some of the fingers of each of the two end portions have flat transverse guide lateral faces perpendicular to the axes of articulation and delimiting in pairs the fingerless spaces.

[0022] According to one embodiment, the fingers of one of the two end portions are each positioned between two planes perpendicular to the axes of articulation and delimiting fingerless spaces of the other of the two end portions.

[0023] According to one embodiment, the rolling face comprises two rolling tracks separated by a guide rib.

[0024] According to another aspect of the invention, it relates to an articulated assembly of at least two links as described above, remarkable in that the fingers of an end portion of a first of the two links are inserted into the fingerless spaces of an end portion of a second of the two links so as to be interlaced, the articulated assembly further comprising a hinge inserted into the holes of each of the interlaced fingers of the first and second links.

[0025] An example of an articulated assembly is that of a caterpillar, which corresponds to an endless chain of such links articulated in pairs. According to one embodiment, the links are identical.

[0026] According to one embodiment, the elastomer material strips of the links are in pairs in partial overlap in a direction perpendicular to the transverse direction of the frame.

[0027] According to another aspect, the invention also relates to a tracked running gear for a support trolley of a railway track laying or renovation machine, comprising a track made up of an articulated assembly of a plurality of links as described above assembled two by two successively and comprising a chassis carrying guide rollers for the track to run on the rolling faces of the track links.

[0028] According to one embodiment, the center distance between two adjacent rollers is greater than or equal to 45 mm and / or less than or equal to 55 mm.

[0029] According to one embodiment, the rollers have axes parallel to the articulation axes of the links, a center distance of the rollers being strictly greater than the value of a center distance taken between the articulation axes of a link and strictly less than the value of twice the center distance taken between the articulation axes of a link.

[0030] According to another aspect, the invention also relates to a support trolley for a railway track laying or renovation machine, notable in that it comprises at least one tracked running gear as described above, preferably at least two lateral running gears. BRIEF DESCRIPTION OF THE FIGURES

[0031] Other features and advantages of the invention will become apparent from the following description, with reference to the attached figures, which illustrate: figure 1 : an isometric perspective view of a support trolley for a railway track laying or renovation machine according to an embodiment; figure 2 : an isometric perspective top view of a tracked undercarriage for the support trolley of the figure 1 ; figure 3 : a front view of the tracked undercarriage of the figure 2 ; figure 4 : an isometric perspective view from below of the tracked undercarriage of the figure 2 ; figure 5 : a view of a track link of the tracked undercarriage of the figure 2 ; figure 6 : an isometric perspective view of part of a track of the tracked undercarriage of the figure 2 ; figure 7 : a view from below of the caterpillar of the figure 6 ; figure 8: a front view of the caterpillar of the figure 6 .

[0032] For clarity, identical or similar elements are identified by identical reference symbols across all figures.

[0033] In the description and claims, to clarify the description and claims, the terminology longitudinal, transverse, and vertical will be adopted without limitation, with reference to the trihedron. X, Y, Z as shown in the figures. DETAILED DESCRIPTION OF A METHOD OF IMPLEMENTATION

[0034] There figure 1 illustrates a view of a support trolley 1 of a railway track laying or renovation machine (not shown), according to one embodiment. The support trolley 1 includes two sets of running gear 200 arranged laterally in relation to the support trolley 1and parallel to each other, symmetrically with respect to a vertical plane parallel to a longitudinal direction X of the support trolley 1.

[0035] Each train of wheels 200 side includes a chassis 210 carrying pebbles 220 guide rail 100 in order to guide the caterpillar 100 during its rotational movement around the rollers 220 guidance.

[0036] The chassis 210 of the two sets of running gear 200 are connected together to form a main chassis of the support trolley 1. This main chassis, as well as the chassis 210 of each of the two rolling stock 200They feature mounting interfaces for attaching, in particular, a set of means for connecting to the track-laying or track-renovating machine. For example, these mounting interfaces are configured to receive at least one deformable parallelogram and means for controlling it, including, for example, a set of jacks, so as to be able to move the support carriage along at least one vertical component. 1. Thus, it is possible to mount the support trolley 1 in an elevated position relative to a rolling surface P0, and lower the support trolley 1 in a position where the tracks 100 rest and are supported against a running surface contained within the running plane P0.

[0037] A running gear 200 according to the method of implementation of the figure 1 is illustrated in more detail on the figures 2 , 3 and 4 .

[0038] The caterpillar 100 consists of an articulated assembly 100' of a plurality of links 10. In this way, each caterpillar 100 of a running gear 200 associated defines an endless chain, or loop, of links 10 articulated in pairs arranged around the rollers 220 guide rails located on the same side of the support carriage 1, associated with one of the lateral running gear 200 given, so as to interpose itself between them and the taxiing plan P0.

[0039] Each link 10 caterpillar 100 includes a one-piece metal part 11 defining two axes of articulation A1, A2 parallel and distant from each other. Each of the two axes of articulation A1, A2 is parallel to a transverse direction Y of the chassis 210 associated. The metal part is a single piece. 11 and features a central portion 12located between the two axes of articulation A1, A2 and two opposite end portions 13, 14 on either side of the central portion 12. Each of the end portions 13, 14 is associated with one of the two axes of articulation A1, A2.

[0040] Each of the end portions 13, 14 includes several fingers 15 parallels separated in pairs by spaces 16 fingerless and pierced by holes 17 aligned along the axis of articulation A1, A2 partner.

[0041] An example of a link 10 This embodiment is illustrated in more detail on the figure 5 The articulated assembly 100' of these links 10 two by two to form the caterpillar 100 is illustrated in more detail on the figures 6 , 7 and 8 .

[0042] The articulated assembly 100' of two of the links 10of the caterpillar 100 is done when the fingers 15 from a portion of the end of the first of the two links 10 two of the assembled links are inserted into the spaces 16 without a finger on the end portion of one of the two links 10 between two of the links assembled so as to be intertwined. The interlacing of the fingers 15 of two end portions 13, 14 of two links 10 distinct allows for alignment of the holes in each of the fingers 15 interlocking and associated, thus forming an opening, here a through hole, delimited by the succession of holes 17 of each of the fingers 15 concerned aligned along an axis parallel to a transverse direction Y of the chassis 210 associated. A hinge 117 inserted into this series of holes 17 aligned from each of the fingers 15interlaced portions of extremities 13, 14 of two links 10 distinct elements allow for a connection between these links. 10. Note that each of the fingers 15 presents a width, along an axis parallel to the transverse direction Y, which can be equal for the same end portion 13, 14, and preferably for the same link 10. However, the width of the fingers 15 can also be variable, for example increasing in width in the transverse direction Y from the center towards the lateral edges of the end portions 13, 14 of the link 10 partner.

[0043] As illustrated in detail on the figures 7 and 8 referring to two links 10, 10' assembled together, each equipped with two articulation axes A1, A2 And A1', A2' respectively: the holes 17 distinct end portions of the two links 10, 10'adjacent spaces allow for the sharing of the two axes of articulation A2, A1' The end portions are joined together so that they are coaxial and interlocked to form the joint between these two links. 10, 10' adjacent.

[0044] In order to keep the hinge 117 in the articulated assembly 100', and in particular to prevent its movement in translation along the geometric axis of articulation A1, A2, This is blocked in both directions by means of translational locking. These locking means may include, for example, a shoulder against which the hinge abuts. 117 on one side of the joint and a weld point located on the other side of the joint to weld it to the link 10 partner.

[0045] For one link 10 given, the one-piece metal part 11 includes: a rolling face 18located on one side of a reference geometric plane P containing the two axes of articulation A1, A2, this bearing surface 18 being located on an inner side of the caterpillar 100. The bearing surface 18 includes two running tracks 181 against which the pebbles roll 220 track guidance 100, the running tracks 181 being separated by a guide rib 180 allowing for simple guidance of the links 10 and therefore of the caterpillar 100 ; and an opposite face 19 to the bearing face 18 located on the other side of the geometric reference plane P, this opposite side 19 being located on an outer side of the caterpillar 100.

[0046] In accordance with the invention, the opposite face 19 is covered with a layer of elastomeric material 20covering the central portion 12 and at least part of each of the fingers 15 of the two end portions 13, 14. This layer of elastomeric material 20 being located on the caterpillar side 100 facing outwards, opposite the chassis 210, On the one hand, it ensures good grip of the trolley on the running surface, contained within the running plane. P0. Furthermore, this layer of elastomeric material 20 prevents any damage to the material against which the support trolley 1 is positioned. In particular, when the support trolley 1 is placed on a section of track without rails, that is to say directly on sleepers 2 of the railway track, the layer of elastomeric material 20 comes to be interposed between the link 10 associated and the crossbeams 2 thus protecting said crossbeams 2.

[0047] Several manufacturing processes for a link 20 can be implemented to allow the placement of the elastomer material layer 20 on the one-piece metal part 11. Among the possible processes, one can mention the vulcanization of a vulcanizable elastomeric material. In this case, vulcanization is carried out with the application of heat and pressure. A variant of vulcanization is cold bonding. It should be noted that the layer of elastomeric material 20 could be reinforced. Such reinforcement could, for example, be a fabric. This fabric could advantageously be colored, for example red, to serve as an easily visible and detectable wear indicator for the layers of elastomeric material. 20 of each of the links 10.

[0048] To ensure continuous support of the support carriage 1 on a layer of elastomeric material 20,the layers of elastomer material 20 links 10 are in pairs in partial overlap in a direction perpendicular to the transverse direction of the chassis 210, namely in a longitudinal direction here. In particular, this characteristic is obtained by the fact that the opposite face 19 of each link 10 is covered by the layer of elastomeric material 20 covering the central portion 12 and at least part of each of the fingers 15 of the two end portions 13, 14, This applies to each of the links. 10 of the caterpillar 100.

[0049] In particular, in this embodiment, the layer of elastomeric material 20 of each of the links 10 covers a main portion in its entirety 21 of the opposite face 19 delimited by the two axes of articulation A1, A2,and covers at least part of the fingers 15 of the two end portions 13, 14 beyond the main portion 21.

[0050] As can be seen in particular on the figure 7 In an assembled position, we obtain links 10, fingers 15 of an end portion of each link 10 of the caterpillar 100 inserted into the spaces 16 without a finger on one of the end portions of the link 10 adjacent, the layer of elastomeric material 20 extending beyond the main portion 21, we obtain at the level of a portion of the extremity 13, 14 of each link 10, an interlacing of layers of elastomeric material 20 adjacent in pairs.

[0051] To guarantee the necessary and sufficient resistance of the elastomer material layers 20,this is configured so that the layer of elastomeric material 20 has a thickness e greater than or equal to 6 mm, preferably greater than or equal to 10 mm, and / or less than or equal to 15 mm, preferably less than or equal to 12 mm. For the same reasons of resistance, the elastomeric material constituting the layer 20 is chosen so as to have a hardness greater than or equal to 92 shore A, and / or less than or equal to 97 shore A.

[0052] The elastomeric material used can be natural or synthetic. Rubber is an example of an elastomeric material that can be used in this application.

[0053] The fingers 15 links 10 have rounded ends, the roundness of each of said fingers 15 being delimited by a connection surface 150rounded forming the junction between a surface of the rolling face 18 and a surface of the opposite face 19. A center of curvature of the connecting surface 150 rounded is preferably contained within the reference geometric plane P containing the two axes of articulation A1, A2. The connection surface 150 rounded so as to be convex. At the level of the fingers 15, the connection surfaces 150 rounded edges define the longitudinal boundary of the link 10 partner.

[0054] The layer of elastomer material 20 features inclined portions, for example curved or chamfered 22, each covering a rounded portion of the rounded end of each of the fingers 15 on the opposite side 19 to the bearing face 18.

[0055] The fingers 15 of each of the two end portions13, 14 have lateral faces 151 transverse guide planes perpendicular to the articulation axes A1, A2 and delimiting the spaces in pairs 16 without a finger, transversely.

[0056] Longitudinally, the spaces 16 without a finger on either of the two end portions 13, 14 have a face 160 forming a background of spaces with a shape complementary to that of the finger 15 that she receives. In particular, the background of the spaces 16 locally delimit the link longitudinally 10 associated and have a concave rounded face whose curvature is equal to that of the connecting surfaces 150 rounded edges of the associated fingers. This facilitates the rotational guidance of the links. 10 articulated in pairs while protecting the connection from the external environment such as dust or rubble.

[0057] The main portion21 of the opposite face 19 of each of the links 10 is flat so as to maximize the contact area and the distribution of forces when the links are supported on the section of track without rail.

[0058] The layer of elastomer material 20 is formed in one continuous piece, that is to say without discontinuity such as a hole, so as to improve its adhesion to the single-piece metal part 11. The layer of elastomer material 20 also has a thickness e constant, even when it covers at least part of the fingers 15 of the two end portions 13, 14 beyond the main portion 21. In this way, consistent protection of the railless section of track is ensured with the track. 100 associated, even in articulated areas, at the level of the joints between links 10.

[0059] As illustrated in detail on the figure 8 Each link is configured so that a center distance d measured between the axes of the joints A1, A2 end portions 13, 14 is greater than or equal to 45 mm and / or, preferably, less than or equal to 55 mm. In this way, the contact surface is maximized and sufficient force distribution is ensured across different links. 10.

[0060] A center-to-center distance D between two pebbles 220 adjacent is greater than or equal to 45 mm and / or less than or equal to 55 mm to maximize the number of load transfer points on each cross member 2.

[0061] Furthermore, the pebbles 220 are mounted to rotate around axes B parallel to the axes of articulation A1, A2 links 10. A center-to-center distance DThe rollers are configured so that the center distance is strictly greater than the center distance value. d caught between the axes of articulation A1, A2 links 10 and strictly less than twice the center distance d caught between the axes of articulation A1, A2 links 10. It is understood that all the rollers have a center distance D identical. Likewise, all the links 10 are identical here and have a center distance d identical.

[0062] To further maximize this number of transfer points, each train 200 is configured so that the axes of rotation B of at least twenty pebbles 220 coplanar among the pebbles 220 are located in the same plane. In the embodiment illustrated here, the center distance D pebbles 220 is configured so that at least three rollers always rest on a crossbar2 and / or, preferably, the length of the support trolley 1 is configured so that it always rests on at least three crossbeams 2, preferably four crossbeams 2. For this, a length of a subset of the pebbles 220 coplanar is preferably greater than or equal to 1800 mm, and preferably even greater than or equal to 1950 mm.

[0063] To prevent premature wear of the chamfers on the crossbeams 2, the chassis 210 of each train 200 includes at least one end portion, bearing pebbles 221 of ends so that, along this end portion, the links 10 evolve along an oblique plane, that is to say, their geometric reference plane P are inclined relative to the running surface P0.

[0064] To facilitate manufacturing and reduce unit cost, all the links 10 of the caterpillar 100, and the support trolley 1 are identical. To allow for successive interlacing of the end portions 13, 14 links 10 two by two, despite being identical, the fingers 15 of one of the two end portions 13, 14 are each positioned between two planes P1, P2 perpendicular to the axes of articulation A1, A2 and delimiting spaces 16 without a finger on the other of the two end portions 13, 14.

[0065] Naturally, the invention described above is by way of example. It is understood that a person skilled in the art is capable of carrying out different embodiments of the invention without departing from its scope.

[0066] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this remains within the scope of the attached claims which define the invention or that technical circumstances make such combinations impossible or meaningless.

Claims

1. A link (10) for a crawler track (100) for a support carriage (1) of a machine for laying or renovating a railway line, comprising a one-piece metal part (11) defining two axes of articulation (A1, A2) that are parallel to and spaced apart from one another, the one-piece metal part (11) having a central portion (12) located between the two axes of articulation (A1, A2) and two opposing end portions (13, 14) on either side of the central portion (12), each of the end portions (13, 14) being associated with one of the two axes of articulation (A1, A2), and comprising a plurality of parallel fingers (15) which are separated in pairs by finger-free spaces (16) and through which holes (17) pass, which holes are aligned along the associated axis of articulation (A1, A2), the one-piece metal part (11) comprising a rolling surface (18) situated on one side of a geometric reference plane (P) that contains the two axes of articulation (A1, A2) and a surface (19) opposite the rolling surface (18), located on another side of the geometric reference plane (P), characterized in that the opposing surface (19) is covered with a layer of elastomeric material (20) that covers the central portion (12) and at least part of each of the fingers (15) of the two end portions (13, 14).

2. The link (10) for a crawler track (100) according to claim 1, characterized in that the layer of elastomeric material (20) completely covers a main portion (21) of the opposite surface (19) delimited by the two axes of articulation (A1, A2), and covers at least part of the fingers (15) of the two end portions (13, 14) beyond the main portion (21).

3. The link (10) for a crawler track (100) according to claim 2, characterized in that the main portion (21) of the opposing surface (19) is flat.

4. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that the layer of elastomeric material (20) has a thickness (e) greater than or equal to 6 mm, preferably greater than or equal to 10 mm and / or less than or equal to 15 mm, preferably less than or equal to 12 mm.

5. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that the end of each of the fingers (15) is rounded, the rounding of each of said fingers (15) preferably being delimited by a rounded connecting face (150) forming the junction between a face of the rolling surface (18) and a face of the opposing surface (19).

6. The link (10) for a crawler track (100) according to claim 5, characterized in that the layer of elastomeric material (20) has inclined, for example curved or chamfered, portions (22), each covering a rounded portion of the end of each of the fingers (15) on the side of the surface (19) opposite the rolling surface (18).

7. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that the layer of elastomeric material (20) is continuous, and preferably has a constant thickness (e).

8. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that the layer of elastomeric material (20) has a hardness greater than or equal to 92 Shore A, and / or less than or equal to 97 Shore A.

9. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that a center-to-center distance (d) between the axes of articulation (A1, A2) of the end portions (13, 14) is greater than or equal to 45 mm and / or less than or equal to 55 mm.

10. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that at least some of the fingers (15) of each of the two end portions (13, 14) have flat transverse guide side faces (151) which are perpendicular to the axes of articulation (A1, A2) and delimit the finger-free spaces (16) in pairs.

11. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that the fingers (15) of one of the two end portions (13, 14) are each positioned between two planes (P1, P2) which are perpendicular to the axes of articulation (A1, A2) and delimit finger-free spaces (16) of the other of the two end portions (13, 14).

12. The link (10) for a crawler track (100) according to any of the preceding claims, characterized in that the rolling surface (18) comprises two rolling tracks (181) separated by a guide rib (180).

13. An articulated assembly (100') of at least two links (10) of one according to any of the preceding claims, the fingers (15) of an end portion of a first of the two links (10) are inserted into the finger-free spaces (16) of an end portion of a second of the two links (10) so as to be criss-crossed, the articulated assembly (100') further comprising a hinge pin (117) inserted into the holes (17) of each of the criss-crossed fingers (15) of the first and second links.

14. The articulated assembly (100') according to claim 13, characterized in that the links (10) are identical.

15. A crawler-track running gear (200) for a support carriage of a machine for laying or renovating a railway line, comprising a crawler track (100) consisting of an articulated assembly (100') of a plurality of links (10) according to claims 13 or 14 assembled successively in pairs and comprising a frame (210) carrying rollers (220) for guiding the crawler track (100) for rolling on the rolling surfaces (18) of the links (10) of the crawler track (100).

16. The crawler-track running gear (200) according to claim 15, characterized in that a center-to-center distance (D) between two adjacent rollers (220) is greater than or equal to 45 mm and / or less than or equal to 55 mm.

17. The crawler-track running gear (200) according to claim 15 or 16, characterized in that the rollers (220) have axes (B) parallel to the axes of articulation (A1, A2) of the links (10), a center-to-center distance (D) of the rollers being strictly greater than the value of a center-to-center distance (e) between the axes of articulation (A1, A2) of a link (10) and strictly less than the value of twice the center-to-center distance (e) between the axes of articulation (A1, A2) of a link (10).

18. A support carriage (1) of a machine for laying or renovating a railway line, characterized in that it comprises at least two crawler-track running gears (200) according to any of claims 15 to 17.