Ladder sleepers

Abstract

To provide a ladder sleeper capable of relaxing a force transmitted to a ballast.SOLUTION: A ladder sleeper 10 comprises a pair of vertical beams 12, an end closure beam 18 and an intermediate closure beam 21. The vertical beams 12 can be arranged below a pair of rails 5 extending in an X direction, and extend in the X direction. The end closure beam 18 is disposed near the end of the vertical beams 12 in the X direction, and extends in a Y direction. The intermediate closure beam 21 is disposed at a position nearer the center C of the vertical beams 12 than the end closure beam 18 in the X direction, extends in the Y direction, and is made of concrete.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a ladder sleeper. [Background technology]

[0002] Ladder sleepers have been put to practical use with the aim of reducing the labor required for maintaining ballasted tracks. A ladder sleeper is a ladder-shaped sleeper in which long vertical beams made of prestressed concrete (PC) are placed along the rails and a pair of vertical beams are connected by steel joints (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3217932 Summary of the Invention [Problem to be solved by the invention]

[0004] When a railway vehicle travels over a rail joint, an impact load acts on the ballast. When a ladder sleeper is installed at a rail joint, the ladder sleeper distributes the impact load and transmits it to the ballast. The force transmitted to the ballast through the ladder sleeper is smaller than the force transmitted to the ballast through a general cross sleeper. However, there is a need to further reduce the force transmitted to the ballast.

[0005] The problem to be solved by the present invention is to provide a ladder sleeper capable of reducing the forces transmitted to the ballast. [Means for solving the problem]

[0006] The ladder sleeper of the present invention has a pair of longitudinal beams, an end beam, and an intermediate beam. The pair of longitudinal beams can be arranged below a pair of rails extending in a first direction, and extend in the first direction. The end beams are arranged near the ends of the pair of longitudinal beams in the first direction, and extend in the up-down direction and in a second direction intersecting the first direction. The intermediate beam is arranged in a position closer to the center of the pair of longitudinal beams than the end beams in the first direction, extends in the second direction, and is made of concrete.

[0007] In the first direction, the ladder sleeper is positioned near the center of the rail joint. When a railway vehicle travels over the rail joint, an impact load acts near the center of the ladder sleeper. The intermediate beam is positioned closer to the centers of the pair of longitudinal beams than the end beams in the first direction. The impact load is dispersed by the concrete intermediate beam and transmitted to the ballast. This reduces the force transmitted to the ballast.

[0008] The ladder sleeper has a plurality of mounting portions. The mounting portions are formed on a pair of longitudinal beams aligned in a first direction and are used to attach a fastening device of a rail. The mounting portions include a first mounting portion located adjacent to a center portion of the pair of longitudinal beams in the first direction. The intermediate beam may be disposed at the position of the first mounting portion in the first direction.

[0009] In the first direction, the position of the first mounting part of the ladder sleeper is arranged at the position of the rail joint. When a railway vehicle travels over the rail joint, an impact load acts on the first mounting part of the ladder sleeper. The intermediate beam is arranged at the position of the first mounting part in the first direction. The impact load is sufficiently dispersed by the intermediate beam and transmitted to the ballast. This satisfactorily reduces the force transmitted to the ballast.

[0010] The ladder sleeper has a plurality of mounting portions. The mounting portions are formed on a pair of vertical beams aligned in a first direction and are used to attach a rail fastening device. The mounting portions include a pair of second mounting portions located on both sides of a center portion of the pair of vertical beams in the first direction. The intermediate beam may be disposed at the position of the pair of second mounting portions in the first direction.

[0011] In the first direction, the center portions of the pair of second mounting portions of the ladder sleeper are positioned at the position of the rail joint. When a railway vehicle travels over the rail joint, an impact load acts on the pair of second mounting portions of the ladder sleeper. The intermediate beam is positioned at the position of the pair of second mounting portions in the first direction. The impact load is sufficiently distributed by the intermediate beam and transmitted to the ballast. This satisfactorily reduces the force transmitted to the ballast.

[0012] The intermediate beam may be a double-fixed beam that is fixed to both of the pair of longitudinal beams. This allows the shock load to be sufficiently distributed and transmitted to the ballast, and therefore the force transmitted to the ballast is sufficiently mitigated.

[0013] The intermediate beam may be a cantilever beam fixed to only one of the pair of longitudinal beams, and may be disposed on only one of the inside and outside of the pair of longitudinal beams in the second direction. When the intermediate beam is a cantilever beam, it can be made of a general reinforced concrete structure. When the intermediate beam is a fixed beam at both ends, it is necessary to introduce tension into the PC steel rod to prevent cracks, but by using a reinforced concrete structure, the tensioning work can be omitted. This improves the productivity of ladder sleepers. When the intermediate beam is placed only on the inside of a pair of longitudinal beams, the ladder sleeper does not expand in the second direction. When the intermediate beam is placed only on the outside of a pair of longitudinal beams, it becomes easier to compact the ballast inside the pair of longitudinal beams.

[0014] The intermediate beam is a cantilever beam fixed to only one of the pair of longitudinal beams, and may be disposed on both the inside and outside of the pair of longitudinal beams in the second direction. This increases the contact area between the intermediate beam and the ballast bed. Impact loads are sufficiently distributed and transmitted to the ballast. Therefore, the force transmitted to the ballast is sufficiently mitigated. Effect of the Invention

[0015] The intermediate beam of the present invention is disposed closer to the center of the pair of longitudinal beams than the end beams in the first direction, extends in the second direction, and is made of concrete, thereby sufficiently reducing the force transmitted to the ballast. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a ballast ladder track using the ladder sleeper of the first embodiment. [Diagram 2] FIG. 2 is a plan view of the ladder sleeper of the first embodiment. [Diagram 3] FIG. 11 is a plan view of a ladder sleeper according to a second embodiment. [Figure 4] FIG. 11 is a plan view of a ladder sleeper according to a first modified example of the second embodiment. [Diagram 5] FIG. 13 is a plan view of a ladder sleeper according to a second modified example of the second embodiment. [Figure 6] FIG. 11 is a perspective view of a ballast ladder track using the ladder sleeper of the third embodiment. [Figure 7] FIG. 11 is a plan view of a ladder sleeper according to a third embodiment. [Figure 8] FIG. 11 is a plan view of a ladder sleeper according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a ladder sleeper according to an embodiment will be described with reference to the drawings. (First embodiment) Fig. 1 is a perspective view of a ballast ladder track using ladder sleepers of the first embodiment. The ballast ladder track 1 is a track in which ladder sleepers 10 are laid on a ballast track bed 3. The ladder sleepers 10 are ladder-shaped vertical sleepers arranged directly below the rails 5. The rails 5 are fixed to the ladder sleepers 10 by fastening devices 6.

[0018] In this application, the Z direction, X direction, and Y direction of the Cartesian coordinate system are defined as follows. The Z direction is the vertical direction, and the +Z direction is the upward direction. The X direction (first direction) is the direction in which the rail 5 and ladder sleeper 10 extend. The Y direction (second direction) is a direction perpendicular to the Z direction and X direction. The X direction and Y direction are horizontal directions. In the X direction and Y direction, the side closer to the center of the ladder sleeper 10 may be called the inside, and the side farther from the center may be called the outside.

[0019] 2 is a plan view of the ladder sleeper of the first embodiment. The ladder sleeper 10 has a pair of longitudinal beams 12, a joint member 14, and an end closure beam (end beam) 18. The ladder sleeper 10 is formed in a ladder shape by rigidly connecting the pair of longitudinal beams 12 with a plurality of joint members 14.

[0020] The vertical beams 12 extend in the X direction. The vertical beams 12 are made of prestressed concrete (PC). PC is concrete prestressed by PC steel. A pair of vertical beams 12 are arranged parallel to each other with a gap in the Y direction. Mounting portions 16 used to attach fastening devices 6 (see FIG. 1) are formed on the upper surfaces of the pair of vertical beams 12. For example, the mounting portions 16 are mounting holes into which bolts are inserted. The mounting holes are formed at positions corresponding to both sides of the rail 5 (see FIG. 1) in the Y direction. A plurality of mounting portions 16 are arranged side by side at approximately equal intervals along the X direction. The number of fastening devices 6 and mounting portions 16 in the X direction is not limited to the examples in the figures.

[0021] The joint member 14 is formed of a steel member such as a steel pipe or a steel bar. For example, the joint member 14 is formed of a straight deformed steel bar extending in the Y direction. The joint member 14 is disposed across a pair of vertical beams 12. Both ends of the joint member 14 in the Y direction are embedded inside the pair of vertical beams 12. A plurality of joint members 14 are disposed in parallel with intervals in the X direction. The joint member 14 may be formed of a steel pipe filled with mortar.

[0022] The end closure beam 18 is disposed near the X-direction ends of the pair of longitudinal beams 12. The end closure beam 18 extends in the Y-direction. The end closure beam 18 is a fixed beam at both ends that is fixed to both of the pair of longitudinal beams 12. The basic structure of the end closure beam 18 is a reinforced concrete structure. However, in order to prevent the end closure beam 18 from cracking, prestress (post-tensioning type) is additionally provided by unbonded PC steel. The end closure beam 18 expands the contact area with the ballast track bed 3. The end closure beam 18 suppresses the X-direction ends of the pair of longitudinal beams 12 from sinking into the ballast track bed 3.

[0023] The ladder sleeper 10 has an intermediate beam 20. The intermediate beam 20 is disposed in a position closer to the center C of the pair of vertical beams 12 in the X direction than the end closure beams 18. The intermediate beam 20 extends in the Y direction. The intermediate beam 20 is made of concrete.

[0024] The intermediate beam 20 in the first embodiment is an intermediate closure beam 21. The intermediate closure beam 21 is a beam fixed at both ends to both of a pair of vertical beams 12. The width of the intermediate closure beam 21 in the X direction is equal to that of the end closure beam 18. As a result, the intermediate closure beam 21 does not interfere with the tamping work of the ballast on the inside of the pair of vertical beams 12.

[0025] The basic structure of the intermediate closure beam 21 is a reinforced concrete structure, similar to that of the end closure beam 18. In order to prevent cracks in the intermediate closure beam 21, prestress (post-tensioning) is provided by unbonded PC steel. The construction method for the intermediate closure beam 21 is as follows. First, the formwork for the area is assembled and the reinforcing bars are placed. Next, the PC steel with its surface unbonded is placed in the specified position. Next, the PC steel is tensioned primarily to remove slack. Next, concrete is poured and hardened to apply prestress to the vertical beam 12. Next, the PC steel is tensioned a second time to apply prestress to the intermediate closure beam 21.

[0026] The above-mentioned multiple mounting portions 16 include a first mounting portion 16a. The first mounting portion 16a is located adjacent to the center portion C of the pair of vertical beams 12 in the X direction. The intermediate closure beam 21 is disposed at the position of the first mounting portion 16a in the X direction.

[0027] As shown in Fig. 1, the rail 5 has a joint S. A joint plate 7 is attached to the side surface of the rail 5 in the Y direction, straddling the joint S. In the X direction, the vicinity of the center of the ladder sleeper 10 is disposed at the position of the joint S. As shown in Fig. 2, the first mounting portion 16a and the intermediate closure beam 21 of the ladder sleeper 10 are disposed at the position of the joint S in the X direction.

[0028] The fastening device 6 attached to the first mounting portion 16a fastens the ends of the rail 5 on both sides in the X direction of the joint S to the vertical beam 12. Therefore, the first mounting portion 16a has mounting holes on both sides in the X direction of a position corresponding to the joint S. As a result, the first mounting portion 16a has two mounting holes on each side of the rail 5 in the Y direction.

[0029] The intermediate closure beam 21 supports the joint S at the same position as the joint S in the X direction. The joint S is a braced joint supported by a so-called braced joint method. The ladder sleeper 10 of the first embodiment is used for the braced joint.

[0030] In the X direction, the vicinity of the center C of the ladder sleeper 10 is disposed at the position of the joint S of the rail 5. When a railway vehicle travels on the joint S of the rail 5, an impact load acts near the center C of the ladder sleeper 10. The intermediate closure beam 21, which is the intermediate beam 20, is disposed near the center C of the pair of longitudinal beams 12 in the X direction, rather than the end closure beam 18. The impact load is dispersed by the intermediate closure beam 21 and transmitted to the ballast. This reduces the force transmitted to the ballast.

[0031] In the X direction, the position of the first mounting portion 16a of the ladder sleeper 10 is located at the position of the joint S of the rail 5. When a railway vehicle travels on the joint S of the rail 5, an impact load acts on the first mounting portion 16a of the ladder sleeper 10. The intermediate closure beam 21 is located at the position of the first mounting portion 16a in the X direction. The impact load is sufficiently dispersed by the intermediate closure beam 21 and transmitted to the ballast. This sufficiently reduces the force transmitted to the ballast. As a result, deterioration such as wear of the ballast and settlement of the ballast track bed 3 can be suppressed.

[0032] The inventors of the present application performed a numerical analysis (simulation) of the pressure on the underside of the ladder sleeper 10 when an impact load acts on the first mounting portion 16a. Compared to when there is no intermediate closure beam 21, when there is an intermediate closure beam 21, the maximum value of the pressure on the underside of the ladder sleeper 10 is reduced by about 10%. It was confirmed that the force transmitted to the ballast is sufficiently mitigated by the intermediate closure beam 21.

[0033] As described above, the width in the X direction of the intermediate closure beam 21 in the first embodiment is equal to that of the end closure beam 18. In contrast, the width in the X direction of the intermediate closure beam 21 may be larger than that of the end closure beam 18. This increases the contact area between the intermediate closure beam 21 and the ballast track bed 3, and sufficiently reduces the force transmitted to the ballast.

[0034] Second embodiment 3 is a plan view of the ladder sleeper of the second embodiment. The ladder sleeper 10 of the second embodiment differs from the first embodiment in that the intermediate beam 20 is an intermediate protrusion 22. Description of the second embodiment in the same parts as the first embodiment may be omitted.

[0035] The intermediate beam 20 in the second embodiment is an intermediate protrusion 22. The intermediate protrusion 22 is a cantilever beam fixed to only one of the pair of longitudinal beams 12. The intermediate protrusion 22 is disposed only on the inner side of the inner and outer sides in the Y direction of the pair of longitudinal beams 12. The intermediate protrusion 22 protrudes to the inner side of the pair of longitudinal beams 12 in the Y direction. The intermediate protrusion 22 protrudes from each of the pair of longitudinal beams 12 to form a pair of intermediate protrusions 22.

[0036] The intermediate protrusion 22 protrudes from the vertical beam 12 in the Y direction by a protrusion amount 22y. Although the intermediate protrusion 22 is a cantilever beam, cracks are unlikely to occur because the protrusion amount 22y is small. While the end closure beam 18 is prestressed, the intermediate protrusion 22 is a general reinforced concrete (RC) structure. The manufacturing process of the intermediate protrusion 22 does not require the work of primary and secondary tensioning of the PC steel. Therefore, the productivity of the ladder sleeper 10 is improved.

[0037] The width 22x in the X direction of the intermediate protrusion 22 is larger than the width in the X direction of the intermediate closure beam 21 of the first embodiment. The product of the protrusion amount 22y and the width 22x is the contact area between the intermediate protrusion 22 and the ballast track bed 3. The sum of the contact areas of the pair of intermediate protrusions 22 is equivalent to the contact area of ​​the intermediate closure beam 21 of the first embodiment.

[0038] The intermediate protrusion 22 is disposed at the position of the first mounting portion 16a in the X direction. The first mounting portion 16a and the intermediate protrusion 22 of the ladder sleeper 10 are disposed at the position of the joint S. That is, the ladder sleeper 10 of the second embodiment is used for a support joint. When a railway vehicle travels over the joint S of the rail 5, an impact load acts on the first mounting portion 16a of the ladder sleeper 10. The impact load is sufficiently dispersed by the intermediate protrusion 22 and transmitted to the ballast. This satisfactorily reduces the force transmitted to the ballast.

[0039] The intermediate protrusions 22 are disposed only on the inner side of the inner and outer sides in the Y direction of the pair of vertical beams 12. Since the intermediate protrusions 22 are not disposed on the outer sides in the Y direction of the pair of vertical beams 12, the ladder sleeper 10 does not expand in the Y direction.

[0040] 4 is a plan view of a ladder sleeper according to a first modified example of the second embodiment. The ladder sleeper 10 according to the first modified example differs from the second embodiment in that the intermediate projections 23 are arranged only on the outer sides of the pair of longitudinal beams 12. Descriptions of the first modified example that are the same as those of the second embodiment may be omitted.

[0041] The intermediate protrusion 23 protrudes outward in the Y direction of the pair of vertical beams 12. The amount of protrusion in the Y direction and the width in the X direction of the intermediate protrusion 23 are similar to those of the intermediate protrusion 22 in the second embodiment. The intermediate protrusion 23 is a general reinforced concrete (RC) structure. The intermediate protrusion 23 is disposed at the position of the first mounting portion 16a in the X direction. The ladder sleeper 10 of the first modified example is used for a support joint. The intermediate protrusion 23 sufficiently distributes the impact load and transmits it to the ballast. Therefore, the force transmitted to the ballast is sufficiently alleviated.

[0042] The intermediate projection 23 of the first modified example is disposed only on the outer side of the inner and outer sides in the Y direction of the pair of longitudinal beams 12. This makes it easier to tamping the ballast on the inner side of the pair of longitudinal beams 12 in the Y direction.

[0043] 5 is a plan view of a ladder sleeper according to a second modified example of the second embodiment. The ladder sleeper 10 according to the second modified example differs from the second embodiment in that the intermediate projections 22, 23 are disposed on both the inside and outside of the pair of longitudinal beams 12. Description of the second modified example in the parts similar to the second embodiment or its first modified example may be omitted.

[0044] The intermediate protrusion 22 protrudes inward in the Y direction of the pair of longitudinal beams 12. The intermediate protrusion 23 protrudes outward in the Y direction of the pair of longitudinal beams 12. The protrusion amount in the Y direction and the width in the X direction of the intermediate protrusions 22, 23 are similar to those of the second embodiment and the first modified example. The sum of the contact areas between the intermediate protrusions 22, 23 and the ballast track bed 3 is larger than the contact area between the intermediate closure beam 21 and the ballast track bed 3 in the first embodiment.

[0045] The intermediate protrusions 22, 23 of the second modified example are disposed on both the inside and outside of the pair of longitudinal beams 12 in the Y direction. This increases the contact area between the intermediate protrusions 22, 23 and the ballast track bed 3. Impact loads are sufficiently distributed and transmitted to the ballast. Therefore, the force transmitted to the ballast is sufficiently mitigated.

[0046] Third embodiment Fig. 6 is a perspective view of a ballast ladder track using the ladder sleeper of the third embodiment. Fig. 7 is a plan view of the ladder sleeper of the third embodiment. The ladder sleeper 10 of the third embodiment differs from the first embodiment in that it is used at a hanging joint. The explanation of the third embodiment in the parts similar to the first embodiment may be omitted.

[0047] 7, the intermediate beam 20 is disposed in a position closer to the center C of the pair of vertical beams 12 in the X direction than the end closure beams 18. The intermediate beam 20 extends in the Y direction. The intermediate beam 20 in the third embodiment is a concrete intermediate closure beam 21 similar to that in the first embodiment.

[0048] The multiple mounting portions 16 include a pair of second mounting portions 16b. The pair of second mounting portions 16b are located on both sides of the center portion C of the pair of vertical beams 12 in the X direction. The intermediate closure beam 21 is disposed at the position of the pair of second mounting portions 16b in the X direction. The intermediate closure beam 21 is disposed at each position of the pair of second mounting portions 16b to form the pair of intermediate closure beams 21.

[0049] As shown in Fig. 6, the rail 5 has a joint S. A joint plate 7 is attached to the side surface of the rail 5 in the Y direction, straddling the joint S. In the X direction, the center of the ladder sleeper 10 is disposed at the position of the joint S. As shown in Fig. 7, the pair of second mounting portions 16b of the ladder sleeper 10 and the center portions C of the pair of intermediate closure beams 21 are disposed at the position of the joint S in the X direction.

[0050] The fastening device 6 attached to the second mounting portion 16b fixes the rail 5 to the ladder sleeper 10 at a position away from the joint S in the X direction. For that reason, the second mounting portion 16b, like the other mounting portions 16, has one mounting hole on each side of the rail 5 in the Y direction.

[0051] The intermediate closure beams 21 support the joint S at the positions of the fastening devices 6 on both sides of the joint S in the X direction. The joint S is a lap joint supported by a so-called lap joint method. The ladder sleeper 10 of the third embodiment is used for a lap joint.

[0052] In the X direction, the center of the ladder sleeper 10 is disposed at the position of the joint S of the rail 5. When a railway vehicle travels over the joint S of the rail 5, an impact load acts on the center C of the ladder sleeper 10. The intermediate closure beam 21, which is the intermediate beam 20, is disposed closer to the center C of the pair of longitudinal beams 12 than the end closure beams 18 in the X direction. The impact load is dispersed by the intermediate closure beam 21 and transmitted to the ballast. This reduces the force transmitted to the ballast.

[0053] In the X direction, the center C of the pair of second mounting portions 16b of the ladder sleeper 10 is disposed at the position of the joint S. When a railway vehicle travels on the joint S of the rail 5, an impact load acts on the pair of second mounting portions 16b of the ladder sleeper 10. The intermediate closure beam 21 is disposed at the position of the pair of second mounting portions 16b in the X direction. The impact load is sufficiently dispersed by the intermediate closure beam 21 and transmitted to the ballast. This sufficiently reduces the force transmitted to the ballast. As a result, deterioration such as wear and settlement of the ballast can be suppressed.

[0054] (Fourth embodiment) 8 is a plan view of the ladder sleeper of the fourth embodiment. The ladder sleeper 10 of the fourth embodiment differs from the third embodiment in that the intermediate beam 20 is an intermediate protrusion 22. Description of the fourth embodiment in the same parts as the third embodiment may be omitted.

[0055] The intermediate beam 20 of the fourth embodiment is an intermediate protrusion 22 similar to that of the second embodiment. The intermediate protrusion 22 is disposed at the position of the pair of second mounting portions 16b in the X direction. In the X direction, the center of the pair of second mounting portions 16b of the ladder sleeper 10 is disposed at the position of the joint S. That is, the ladder sleeper 10 of the fourth embodiment is used for a hanging joint. When a railway vehicle travels over the joint S of the rail 5, an impact load acts on the pair of second mounting portions 16b of the ladder sleeper 10. The impact load is sufficiently dispersed by the intermediate protrusion 22 and transmitted to the ballast. This satisfactorily reduces the force transmitted to the ballast.

[0056] The intermediate protrusion 22 in the fourth embodiment is disposed only on the inner side of the inner and outer sides in the Y direction of the pair of longitudinal beams 12, as in the second embodiment. Instead of the intermediate protrusion 22, an intermediate protrusion 23 similar to the first modified example of the second embodiment may be adopted. The intermediate protrusion 23 is disposed only on the outer side of the inner and outer sides in the Y direction of the pair of longitudinal beams 12. As in the second modified example of the second embodiment, the intermediate protrusion 22 and the intermediate protrusion 23 may be adopted simultaneously.

[0057] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and modifications, combinations, deletions, etc. of the configurations are also included within the scope that does not deviate from the gist of the present invention.

[0058] The intermediate beam 20 in the embodiment is disposed at the position of the first mounting portion 16a or the pair of second mounting portions 16b in the X direction. Alternatively, the intermediate beam 20 may be disposed between adjacent mounting portions 16. Even in this case, the intermediate beam 20 is disposed closer to the center C of the pair of vertical beams 12 than the end closure beam 18 in the X direction. This reduces the force transmitted to the ballast.

[0059] The end beam in the embodiment is an end closure beam 18, which is a beam fixed at both ends and fixed to both of the pair of longitudinal beams 12. In contrast, the end beam may be an end protrusion similar to the intermediate protrusions 22, 23. The end protrusion is a cantilever beam fixed to only one of the pair of longitudinal beams 12. The end protrusion is a general reinforced concrete structure. This improves the productivity of ladder sleepers. [Explanation of symbols]

[0060] C...center portion, S...joint, 5...rail, 6...fastening device, 10...ladder sleeper, 12...longitudinal beam, 16...mounting portion, 16a...first mounting portion, 16b...second mounting portion, 18...end closure beam (end beam), 20...intermediate beam, 21...intermediate closure beam (intermediate beam), 22...intermediate protrusion (intermediate beam), 23...intermediate protrusion (intermediate beam).

Claims

1. A pair of longitudinal beams extending in a first direction and capable of being disposed below a pair of rails extending in the first direction; an end beam disposed near the ends of the pair of vertical beams in the first direction and extending in a second direction intersecting the up-down direction and the first direction; An intermediate beam made of concrete arranged at a position closer to the center of the pair of vertical beams than the end beams in the first direction and extending in the second direction; a plurality of mounting portions formed on the pair of longitudinal beams aligned in the first direction and used for mounting a fastening device of the rail; The plurality of mounting portions include a first mounting portion that is not formed in a central portion of the pair of longitudinal beams in the first direction and is located adjacent to the central portion of the pair of longitudinal beams in the first direction, The first mounting portion has mounting holes on both sides in the first direction at a position corresponding to the joint of the rail in the first direction, for mounting the ends of the rail on both sides of the joint in the first direction to the pair of vertical beams, The intermediate beam is disposed at a position of the first mounting portion in the first direction. Ladder sleepers.

2. A pair of longitudinal beams that can be disposed below a pair of rails extending in a first direction and extend in the first direction; an end beam disposed near the ends of the pair of vertical beams in the first direction and extending in a second direction intersecting the up-down direction and the first direction; An intermediate beam made of concrete arranged at a position closer to the center of the pair of vertical beams than the end beams in the first direction and extending in the second direction; a plurality of mounting portions formed on the pair of longitudinal beams aligned in the first direction and used for fastening the rail; The plurality of mounting portions include a pair of second mounting portions that are not formed in the central portions of the pair of vertical beams in the first direction and are located adjacent to both sides of the central portions of the pair of vertical beams in the first direction, the pair of second mounting portions have mounting holes for mounting the rail to the pair of vertical beams at positions spaced in the first direction from central portions of the pair of vertical beams where joints of the rail are located in the first direction, The intermediate beam is disposed at a position of the pair of second mounting portions in the first direction. Ladder sleepers.

3. The intermediate beam is a double-fixed beam fixed to both of the pair of vertical beams.

3. A ladder sleeper as claimed in claim 1 or 2.

4. The intermediate beam is a cantilever beam fixed to only one of the pair of vertical beams, and is disposed on only one of the inner side and the outer side of the pair of vertical beams in the second direction.

3. A ladder sleeper as claimed in claim 1 or 2.

5. The intermediate beam is a cantilever beam fixed to only one of the pair of longitudinal beams, and is disposed on both the inside and the outside of the pair of longitudinal beams in the second direction.

3. A ladder sleeper as claimed in claim 1 or 2.

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