Side beam of a bogie frame for a railway vehicle

Abstract

A side beam (20) of a railway vehicle bogie frame (10) in which two such side beams define respective lateral sides of the bogie frame in relation to a longitudinal direction (L) of the railway vehicle (1) and a crossbeam (11) extends over a transverse direction (T) of the railway vehicle to join the side beams, the bogie frame being configured to carry, in use, front and rear wheelsets (3). The side beam is formed of discrete structural members comprising an elongate centre plate (21) which extends between first and second end portions (21a) thereof in the longitudinal direction between positions occupied, in use, by the wheelsets, a thickness direction of the centre plate being parallel to the transverse direction, and first and second suspension mounts (22) configured for mounting wheelset suspension elements thereto. The first and second suspension mounts are cantilevered from respectively the first and second end portions of the centre plate such that each suspension mount extends upwardly and longitudinally away from a respective junction with its end portion of the centre plate to define a space below the suspension mount for joining the suspension elements to the respective wheelset. At the respective junction each suspension mount has a greater width in the transverse direction than the thickness of the centre plate such that the suspension mounts protrude outwardly in the transverse direction from the centre plate. The discrete structural members are joined together by respective bolt connections (30).

Description

Field of the Invention

[0001] The present invention relates to a side beam of a bogie frame for a railway vehicle.Background

[0002] Due to increasing societal and political demands for decarbonisation, lightweight construction is a constant concern in transport structures. Although railway vehicles already provide significant environmental benefits compared to other modes of vehicular transport, structural weight reduction remains an important issue. Lightweight, welded, aluminium alloy bogie frames have been proposed to reduce the weight of railway vehicles. However, from viewpoints of strength, reliability and maintainability there is still scope for improvement in the welded joints of such frames.

[0003] Bogie frames have structural components for transmitting various loads between bodies of railway vehicles supported by the frames and wheelsets carried by the frames. In addition to such structural components, bogie frames typically also provide mounting positions for equipment used in train operation, such as motors, suspension items, bearings, brake units etc. Such equipment occupies space, and there is also scope for improvement in how such space is provided around bogie frames.

[0004] The present invention has been devised in light of the above considerations.Summary of the Invention

[0005] According to a first aspect of the present invention, there is provided a side beam of a railway vehicle bogie frame in which two such side beams define respective lateral sides of the bogie frame in relation to a longitudinal direction of the railway vehicle and a crossbeam extends over a transverse direction of the railway vehicle to join the side beams, the bogie frame being configured to carry, in use, front and rear wheelsets. The side beam is formed of discrete structural members comprising: an elongate centre plate which extends between first and second end portions thereof in the longitudinal direction between positions occupied, in use, by the wheelsets, a thickness direction of the centre plate being parallel to the transverse direction, and first and second suspension mounts configured for mounting wheelset suspension elements thereto, the first and second suspension mounts being cantilevered from respectively the first and second end portions of the centre plate such that each suspension mount extends upwardly and longitudinally away from a respective junction with its end portion of the centre plate to define a space below the suspension mount for joining the suspension elements to the respective wheelset, at the respective junction each suspension mount having a greater width in the transverse direction than the thickness of the centre plate such that the suspension mounts protrude outwardly in the transverse direction from the centre plate; and wherein the discrete structural members are joined together by respective bolt connections.

[0006] The use of bolt connections in the side beam provides several advantages compared to e.g. welded joints. For example, a bolted joint formed by a bolt connection avoids subjecting the side beams to residual stresses that may be caused by a welded joint, and also avoids the possibility of heat affected zones adjacent the weld in the aluminium alloy. Also, a bolt connection can be easily installed, repaired or replaced, particularly when it is accessibly located on the outside of the bogie frame. Therefore, the reliability and repairability of the side beam can be improved.

[0007] Moreover, by extending the suspension mounts in the transverse direction relative to the centre plate at the junctions, the side beam of the present invention can provide an additional space outward of the centre plate and longitudinally bounded at the end portions of the plate by the suspension mounts. This space may be used to house additional components and modules such as devices involved in the operation of the railway vehicle. For example, the space may house a yawning damper and / or an anti-rolling system. These devices are conventionally attached on the outside of the bogie frame, increasing the width of the bogie in the transverse direction. However, by housing the devices in the additional space, bogie frames using the side beam of the present invention can have a reduced width.

[0008] The respective bolt connections may transfer substantially all the load between the discrete structural members of the side beam. In this way these bolt connections may reduce or altogether eliminate the need for other connection methods, for example welded connections, between the discrete structural members.

[0009] The structural members may be formed of aluminium alloy. Such alloy enables lightweight structures having good mechanical properties.

[0010] Preferably, the centre plate of the side beam is formed of wrought aluminium alloy. For example, the centre plate may be forged, extruded, or otherwise worked into shape. The centre plate may then be subjected to further processes such as machining to achieve a finished shape. Advantageously, wrought aluminium alloy is generally stronger and tougher than cast alloy, which allows the thickness of the centre plate to be reduced while maintaining its mechanical properties.

[0011] In contrast, the suspension mounts are preferably formed of cast aluminium alloy. For example, the suspension mounts may be sand cast, die cast, continuously cast, pressure die cast or one-shot cast. The suspension mounts may be machined post-casting to achieve a finished state. Advantageously, casting the aluminium alloy enables the formation of intricate three-dimensional shapes.

[0012] The discrete structural members of the side beam may further comprise one or more reinforcing components at each of the junctions for supporting the greater width of the respective suspension mount relative to the thickness of the centre plate. In particular, the reinforcing members may increase the side beam's resistance to bending and / or torsional stresses. The reinforcing components may be formed of wrought aluminium alloy. For example, the reinforcing components may be forged, extruded, or otherwise worked into shape. They may then be machined into final shape.

[0013] Each of the side beam's suspension mounts may have a base portion that forms the junction with the respective end portion of the centre plate, an inner side of the base portion being joined onto a top surface of the respective end portion by one or more bolt connections which extend through the base portion and the end portion, and wherein the one or more reinforcing components of each junction may include a subsidiary plate which extends parallel to the centre plate, an outer side of the base portion being joined onto a top surface of the subsidiary plate by one or more bolt connections which extend through the base portion and the subsidiary plate. In other words, each suspension mount may be supported on an inner side (by the centre plate) and an outer side (by the subsidiary plate). This configuration extends the junction in the transverse direction, which helps the junction to resist bending and torsional forces. The subsidiary plate may be spaced in the transverse direction from the centre plate to further help resist these forces.

[0014] The one or more reinforcing components of each junction may further include an angle brace having first and second walls for bracing the subsidiary plate to the centre plate, the first wall being joined, or joinable in use, to an outer surface of the centre plate by one or more bolt connections which extend through the first wall and the centre plate, and the second wall being joined to a side surface of the subsidiary plate by one or more bolt connections which extend through the second wall and the subsidiary plate. The angle brace therefore connects the subsidiary plate to the centre plate, and may help the side beam to better resist bending and torsional forces. Preferably the angle brace includes one or more strengthening webs extending between the first and second walls.

[0015] One or more steel reinforcement plates may extend across each junction between the respective end portion of the centre plate and the respective suspension mount. This can be particularly advantageous when the structural members of the side beam are formed of aluminium alloy. Steel is denser than aluminium alloy, but it also stronger and stiffer. Therefore the use of some steel reinforcement across each junction may significantly strengthen and stiffen the junction against bending and torsional forces for only a relatively small increase in overall weight. In addition, the steel reinforcement plates can help to prevent separation of the structural members at the junction under loading from the vehicle body. Inner and outer steel reinforcement plates may extend across respectively inner and outer sides of a given junction.

[0016] At each junction the transverse width of the suspension mount may be greater than the transverse thickness of the centre plate by a factor of at least 2, and preferably at least 3.

[0017] The centre plate may taper at its end portions such that the vertical height of the centre plate is greater at its centre than at its ends. This can also help to increase the spaces below the suspension mounts for joining the suspension elements to the respective wheelset.

[0018] Each bolt connection joining the discrete structural members of the side beam may be formed by a bolt that penetrates a through-hole in at least one of the structural members and is received in a threaded receiving hole in another of the structural members or, in use, the crossbeam. Providing the threaded receiving hole allows the bolt connection to be completed without using a nut. Helical, e.g. steel, inserts may reinforce the threads of the receiving holes. This can be particularly beneficial for holes formed in aluminium alloy structural members.

[0019] The bolt connections joining the discrete structural members of the side beam may further comprise sensors to measure an axial strain in the bolts of the bolt connections. The sensors may be embedded in the bolts of the bolt connections. The sensors may be strain gauges such as piezoelectric strain sensors.

[0020] According to a second aspect of the present invention, there is provided a bogie frame for a railway vehicle comprising: two of the side beams according to the first aspect of the present invention defining respective lateral sides of the bogie frame in relation to a longitudinal direction of the railway vehicle, and a crossbeam extending over a transverse direction of the railway vehicle to join the side beams, wherein the crossbeam is joined to the centre plate of each side beam by respective bolt connections. The use of bolt connections to join the crossbeam to each side beam provides advantages compared to e.g. welded joints, as discussed above under the first aspect.

[0021] The bolt connections joining the crossbeam to the centre plates may transfer substantially all the load between the crossbeam and the centre plates. In this way these bolt connections may reduce or altogether eliminate the need for other connection methods between the crossbeam and the centre plates.

[0022] The crossbeam may be formed of aluminium alloy. Again, this enables a lightweight structure having good mechanical properties.

[0023] The crossbeam may be formed of cast aluminium alloy. For example, the cross beam can be formed from plural cast sub-components. The crossbeam or its sub-components may be sand cast, die cast, continuously cast, pressure die cast or one-shot cast. The crossbeam or its sub-components may be machined to achieve a finished shape.

[0024] Each bolt connection joining the crossbeam to one of the centre plates may be formed by a bolt that penetrates a through-hole in the centre plate and is received in a threaded receiving hole in the crossbeam. Providing the threaded receiving hole allows the bolt connection to be completed without using a nut. Helical, e.g. steel, inserts may reinforce the threads of the receiving holes.

[0025] The bolt connections joining the crossbeam to the centre plates may further comprise sensors to measure axial strain in the bolts of the bolt connections. The sensors may be embedded in the bolts of the bolt connections. The sensors may be strain gauges such as piezoelectric strain sensors.

[0026] The bolt connections joining the crossbeam and the centre plates may further comprise shims, which are located at the interfaces between the crossbeam and the centre plates. The shims can thereby fill any gaps between the crossbeam and the centre plates to control the transverse spacing of the centre plates. The shims may be surface treated, e.g. grinded and / or coated (e.g. painted), to increase their frictional interaction with the crossbeam and the centre plates, and thereby transfer shear loads between the crossbeam and the centre plates. In this way, the shims can help to reduce bending loads on the bolt connections, which could otherwise lead to premature bolt failure.

[0027] According to a third aspect of the present invention, there is provided a bogie for a railway vehicle comprising the bogie frame according to the second aspect of the present invention and front and rear wheelsets carried by the bogie frame.

[0028] According to a fourth aspect of the present invention, there is provided a railway vehicle comprising one or more of the bogies according to the third aspect of the present invention.

[0029] The invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.Summary of the Figures

[0030] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which: Figure 1 shows a schematic side-view of an end of a railway vehicle including a bogie; Figure 2 shows a bogie frame in a perspective view; Figure 3 shows a side beam of the bogie frame depicted in Figure 2 in a perspective view; Figure 4 shows the side beam depicted in Figure 3 in a top-down view; Figure 5 shows the side beam depicted in Figure 3 in an exploded view; Figure 6 shows a close up view of the centre plate of the side beam depicted in Figure 3; Figure 7 shows a close up view of a subsidiary plate of the side beam depicted in Figure 3; Figure 8 shows a close up view of an angle brace of the side beam depicted in Figure 3; Figure 9 shows the bogie frame depicted in Figure 2 in an exploded view; Figure 10 shows a portion of a variant bogie frame in an exploded view; Figure 11 shows a variant side beam in a perspective view; and Figure 12 shows a bogie frame including the side beam of Figure 11 in a perspective view. Detailed Description of the Invention

[0031] Further background to the present invention, and aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

[0032] Figure 1 shows a schematic side-view of an end of a railway vehicle 1 including a bogie 5. The bogie 5 is positioned underneath the railway vehicle 1 over the track 4. The bogie 5 comprises a bogie frame 10 which supports the floor of the railway vehicle 1 and carries two wheelsets 3. A further similar bogie (not shown) is provided at the other end of the vehicle. The bogies 5 provide stability, absorb vibrations, and reduce the impact of centrifugal forces on curved sections of the track 4.

[0033] Figure 2 shows a bogie frame 10 in a perspective view. The bogie frame 10 comprises two side beams 20 and a crossbeam 11. The two side beams define respective lateral sides of the bogie frame in relation to a longitudinal direction L of the railway vehicle 1 and the crossbeam extends over a transverse direction T of the railway vehicle to join the side beams.

[0034] The side beams 20 are formed from discrete structural members, as discussed in more detail below, made from aluminium alloy(s). The crossbeam may also be made from aluminium alloy. The crossbeam may be a single cast component or it may be formed of cast sub-components. For example, in Figure 2 the crossbeam 11 comprises four cast sub-components 11a to 11d.

[0035] Figures 3 and 4 show an example of the side beam 20 in perspective and top-down views respectively. Figure 5 shows an exploded view of the side beam. Figures 6 to 8 show close up views of different discrete structural members of the side beam. Figure 9 shows an exploded view of the bogie frame 10.

[0036] The discrete structural members of the side beam 20 include: an elongate centre plate 21 extending in the longitudinal direction L with the thickness direction of the plate in the transverse direction T, suspension mounts 22 at opposite ends of the centre plate, and additional reinforcing components 23, 24 at junctions between the centre plate and the suspension mounts. Most of the structural members of each side beam are joined together with smaller bolt connections 30, while each side beam is joined at its centre plate to a respective end of the crossbeam 11 with larger bolt connections 14. However, as discussed below, some of these larger bolt connections 14 have a further function of also joining side beam structural members together.

[0037] Each suspension mount 22 includes a base portion 22a that forms the junction with a respective end portion 21a of the centre plate and an arcuate main body portion 22b on which wheelset suspension elements (not shown) are mounted. The suspension mounts 22 are formed of cast aluminium alloy, the casting process being suitable for forming the relatively complex shape of the mounts, and aluminium alloy allowing low weight to be combined with good mechanical properties.

[0038] The suspension mounts 22 are cantilevered from the centre plate 21. In particular, the arcuate main body portions 22b rise upwardly and longitudinally away from the end portions 21a of the centre plate 21 to provide a space below the suspension mounts in which the wheelset suspension elements are situated.

[0039] The base portions 22a of the suspension mounts 22 have a greater transverse width relative to the thickness of the centre plate 21. This causes the suspension mounts to protrude outwardly in the transverse direction at their junctions with the centre plate, with only an inboard strip of each base portion 22a being in direct physical contact with the top surface of the centre plate. Outward of this strip, each suspension mount is supported by the additional reinforcing components in the form of a subsidiary plate 23 and an angle brace 24. At each junction the transverse width of the suspension mount may be greater than the transverse thickness of the centre plate by a factor of at least 2, and preferably at least 3. As shown best in Figure 4, the relative overall dimensions of the suspension mounts and the centre plate cause the side beam 20 to narrow to a waist at the middle of the centre plate, leaving a protected space 25 outboard of the middle of the plate for mounting equipment to the bogie frame 10. This space is particularly useful for mounting devices that are required to be or are preferably mounted on the outside of the bogie frame (e.g. a yawing damper and / or an anti-rolling system). In addition, the relatively thinness of the centre plate 21 helps to reduce the structural weight of the side beam 20.

[0040] Each bolt connection 14, 30 typically comprises a respective fastening bolt 14a, 30a which is inserted into a through-hole in one component and screwed into a threaded hole in another component (thereby avoiding a need for separate tightening nuts to complete the bolt connections). In general, several bolt connections connect each pair of joined components to provide redundancy and reduce the load on individual connections. Threaded holes in aluminium alloy components may be reinforced by helical steel inserts, e.g. Helicoils ™< .

[0041] The centre plate 21 of the side beam 20 is formed of wrought and machined aluminium alloy for enhanced strength and toughness. Referring to the close up view of Figure 6, the plate has through-holes 21e and threaded receiving holes 21b for its bolt connections 30, and larger diameter through-holes 21d for receiving the larger fastening bolts 14a. The centre plate may have one or more voids 21f to reduce the weight of the plate. Additional through-holes 21c may be incorporated into the centre plate to attach additional items to the side beam 20, as discussed below with respect to Figures 11 and 12. The centre plate tapers at its end portions 21a such that the vertical height of the centre plate is greater at its centre than at its ends. This increases the space below the suspension mounts 22 for joining the suspension elements to the respective wheelset.

[0042] The subsidiary plates 23 and angle braces 24 are also formed of wrought and machined aluminium alloy for enhanced strength and toughness. Each subsidiary plate 23 is positioned parallel to, but spaced in the transverse direction from, the respective end portion 21a of the centre plate 21, and is joined by bolt connections 30 to the base portion of the suspension mount 22 such that an outboard strip of the base portion is in direct physical contact with the top surface of the subsidiary plate. The respective angle brace 24 then has: a first wall 24a which is joined by bolt connections 14 to the centre plate, and a 90° second wall 24b which is joined by bolt connections 30 to a side surface of the subsidiary plate.

[0043] Referring to the close up view of Figure 7, each subsidiary plate 23 has through-holes 23b and threaded receiving holes 23a, 23c for its bolt connections 30. Like the centre plate 21, the subsidiary plate may also have one or more weight-saving voids 23e. Additional holes 23d may be incorporated into the subsidiary plate to attach additional items to the side beam 20, as discussed below with respect to Figures 11 and 12.

[0044] Referring to the close up view of Figure 8, the first wall 24a and the second wall 24b of each angle brace 24 are strengthened and rigidified by one or more strengthening webs 24c which extend between the two walls. The brace comprises through-holes 24f for its bolt connections 30 to the subsidiary plate 23, and through-holes 24d for its bolt connections 14 to the centre plate 21. The fastening bolts 14a of these bolt connections 14 penetrate the through-holes 24d, as well as aligned through-holes 21d in the centre plate, before screwing into threaded holes 11e in the crossbeam 11. They thus serve dual functions of joining the angle brace to the centre plate, and joining the side beam as a whole to the crossbeam. Additional holes 24e may be incorporated into the angle brace to attach additional items to the side beam 20, as discussed below with respect to Figures 11 and 12.

[0045] The spacing of the subsidiary plate 23 from the centre plate 21, and its bracing by the angle brace 24 increases the side beam's resistance to bending and torsional forces.

[0046] The use of the bolt connections 14, 30 can simplify the assembly of the bogie frame 10, particularly when the heads of the fastening bolts 14a, 30a are accessibly positioned on the outside of the frame where they are tightenable with conventional tools such as torque wrenches. The structural members of the side beam can then also be easily replaced if they are damaged. This applies particularly to the subsidiary plates 23 which are most prone to damage from ballast strikes. In addition, the bolt connections can be readily accessible for safety inspection.

[0047] The bolt connections 14 may additionally comprise shims at the interfaces between the crossbeam 11 and the side beams 20. For example, as shown in Figure 9, shims 14b are located on the inner face of the centre plate 21. The shims may be used to fill any gaps between the crossbeam and the side beams and thereby regulate the transverse spacing between the centre plates 21. Conveniently, each shim may be a washer through which the respective fastening bolt 14a is inserted. This ensures that the shims stay in location as long as the bolts are not removed. Advantageously, the shims may be surface treated to increase their frictional interaction with the crossbeam and the centre plates, and thereby promote the transfer of shear loads between the crossbeam and the centre plates and thereby reduce bending loads on the bolts 14a.

[0048] Figure 10 shows a portion of a variant of the bogie frame 10 in an exploded view. In the variant, the bolt connections 14 additionally comprise sensors 14c to measure axial strain in the fastening bolts 14a. In this way the condition of the bolt connections can be monitored. For example, the fastening bolts 14a may have a central cavity housing a strain gauge (such as piezoelectric strain sensor) with connection wires to power and interrogate the gauge extending therefrom.

[0049] Figure 11 shows a variant of the side beam in a perspective view, and Figure 12 shows a bogie frame including the side beam of Figure 11 in a perspective view. In this variant, the side beam 20 additionally comprises steel reinforcement plates 25 to further strengthen the side beam against bending and torsional forces, and to help prevent separation of the side beam structural members under loading from the vehicle body. In particular, steel reinforcement plates 25 can be attached to the inner and outer sides of the side beam to extend across the junctions between the end portions 21a of the centre plate 21 and the suspension mounts 22.

[0050] Further bolt connections 25a can be used to join the reinforcement plates 25 to the side beam 20. In particular, the bolt connections may have fastening bolts which are inserted through through-holes in the reinforcement plates. On one side of each junction these bolts then screw into threaded holes 22c (see Figure 5) formed in the suspension mounts 22. On the other side of the junction, the bolts screw into threaded holes 23d (see Figure 7) formed in the subsidiary plate 23 if the plate is on the outer side of the side beam, or into threaded holes 24e (see Figure 8) formed in the angle brace 24 if the plate is on the inner side of the side beam (in this case the bolts having also penetrated the through-holes 21c formed in the centre plate 21 - see Figure 6).

[0051] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0052] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0053] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0054] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0055] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word "comprise" and "include", and variations such as "comprises", "comprising", and "including" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0056] It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional and means for example + / - 10%.

Claims

1. A side beam (20) of a railway vehicle bogie frame (10) in which two such side beams define respective lateral sides of the bogie frame in relation to a longitudinal direction (L) of the railway vehicle (1) and a crossbeam (11) extends over a transverse direction (T) of the railway vehicle to join the side beams, the bogie frame being configured to carry, in use, front and rear wheelsets (3); wherein the side beam (20) is formed of discrete structural members comprising: an elongate centre plate (21) which extends between first and second end portions (21a) thereof in the longitudinal direction (L) between positions occupied, in use, by the wheelsets (3), a thickness direction of the centre plate (21) being parallel to the transverse direction (T), and first and second suspension mounts (22) configured for mounting wheelset suspension elements thereto, the first and second suspension mounts being cantilevered from respectively the first and second end portions (21a) of the centre plate (21) such that each suspension mount extends upwardly and longitudinally away from a respective junction with its end portion of the centre plate to define a space below the suspension mount (22) for joining the suspension elements to the respective wheelset (3), at the respective junction each suspension mount having a greater width in the transverse direction (T) than the thickness of the centre plate (21) such that the suspension mounts protrude outwardly in the transverse direction (T) from the centre plate; and wherein the discrete structural members are joined together by respective bolt connections (30).

2. The side beam (20) according to claim 1, wherein the respective bolt connections (30) transfer substantially all the load between the discrete structural members.

3. The side beam (20) according to claim 1 or 2, wherein the centre plate (21) is formed of wrought aluminium alloy, and the suspension mounts (22) are formed of cast aluminium alloy.

4. The side beam (20) according to any preceding claim, wherein the discrete structural members further comprise one or more reinforcing components (23, 24) at each of the junctions for supporting the greater width of the respective suspension mount (22) relative to the thickness of the centre plate (21).

5. The side beam (20) according to claim 4, wherein each suspension mount (22) has a base portion (22a) that forms the junction with the respective end portion (21a) of the centre plate, an inner side of the base portion (22a) being joined onto a top surface of the respective end portion (21a) by one or more bolt connections (30) which extend through the base portion and the end portion, and wherein the one or more reinforcing components of each junction include a subsidiary plate (23) which extends parallel to the centre plate (21), an outer side of the base portion (22a) being joined onto a top surface of the subsidiary plate (23) by one or more bolt connections (30) which extend through the base portion and the subsidiary plate.

6. The side beam (20) according to claim 5, wherein the one or more reinforcing components of each junction further include an angle brace (24) having first and second walls (24a, 24b) for bracing the subsidiary plate (23) to the centre plate (21), the first wall (24a) being joined. or joinable in use. to an outer surface of the centre plate (21) by one or more bolt connections (30) which extend through the first wall and the centre plate, and the second wall (24b) being joined to a side surface of the subsidiary plate (23) by one or more bolt connections (30) which extend through the second wall and the subsidiary plate.

7. The side beam (20) according to any preceding claim, wherein at each junction the transverse width of the suspension mount (22) is greater than the transverse thickness of the centre plate (21) by a factor of at least 2.

8. The side beam (20) according to any preceding claim, wherein the centre plate (21) tapers at its end portions (21a) such that the vertical height of the centre plate is greater at its centre than at its ends.

9. The side beam (20) according to any preceding claim, wherein each bolt connection (30) is formed by a bolt (30a) that penetrates a through-hole in at least one of the structural members and is received in a threaded receiving hole in another of the structural members or, in use, the crossbeam.

10. A bogie frame (10) for a railway vehicle (1) comprising: two of the side beams (20) according to any preceding claim defining respective lateral sides of the bogie frame (10) in relation to a longitudinal direction (L) of the railway vehicle (1), and a crossbeam (11) extending over a transverse direction (T) of the railway vehicle (1) to join the side beams (20), wherein the crossbeam (11) is joined to the centre plate (21) of each side beam (20) by respective bolt connections (14).

11. The bogie frame (10) according to claim 10, wherein the bolt connections (14) joining the crossbeam (11) to the centre plates (21) transfer substantially all the load between the crossbeam and the centre plates.

12. The bogie frame (10) according to claim 10 or 11, wherein each bolt connection (14) joining the crossbeam (11) to one of the centre plates (21) is formed by a bolt (14a) that penetrates a through-hole (21d) in the centre plate and is received in a threaded receiving hole (11e) in the crossbeam (11).

13. The bogie frame (10) according to any of claims 10 to 12, wherein the bolt connections (14) joining the crossbeam (11) to the centre plates (21) further comprise sensors (14c) to measure axial strain in the bolts (14a) of the bolt connections (14).

14. The bogie frame (10) according to any of claims 10 to 13, wherein the bolt connections (14) joining the crossbeam (11) and the centre plates (21) further comprise shims (14b), which are located at the interfaces between the crossbeam and the centre plates.

15. A railway vehicle (1) comprising one or more bogies (5), wherein the or each bogie comprises the bogie frame (10) according to any of claims 10 to 14 and front and rear wheelsets (3) carried by the bogie frame.

Images