WO2023037095A1

WO2023037095A1 - Conductor rail

Info

Publication number: WO2023037095A1
Application number: PCT/GB2022/052233
Authority: WO
Inventors: Steve DARE; Lee BRUN
Original assignee: Brecknell Willis and Co Ltd
Current assignee: Brecknell Willis and Co Ltd
Priority date: 2021-09-10
Filing date: 2022-09-01
Publication date: 2023-03-16
Anticipated expiration: 2024-03-10
Also published as: GB2610603A; GB202112904D0; GB2610603B

Abstract

The present invention relates to a method for manufacturing a conductor rail. The method involves the steps of providing a main body of the conductor rail, providing a cap to be received onto the main body, performing a first forming operation in which the cap is plastically deformed to obtain a desired pre-form shape, placing the cap onto the main body and performing a second forming operation in which the cap is plastically deformed about the main body to create a mechanical bond between the main body and the cap. Advantageously, it has been found that by performing an initial forming operation wherein the cap is deformed to obtain a desired pre-form shape helps to reduce material "spring-back" and hence a closer contact-to-contact bond between the main body and the cap can be achieved.

Description

CONDUCTOR RAIL

FIELD OF THE INVENTION

The present invention relates to a method and a kit of parts for manufacturing a conductor rail, and to a rail installation comprising the same.

BACKGROUND OF THE INVENTION

Conductor rails are commonly used in modern electric railway systems. One kind of conductor rail that is commonly used in the rail industry is the so called “composite conductor rail” as is described in UK Patent GB2231544.

Conductor rails of this kind typically comprise a main body section and a contact face. The main body section and contact face are provided as separate components and therefore require a joining operation in order to produce the finished conductor rail part.

One method commonly used for joining the main body to the contact face involves crimping the contact face around the main body. However, this method tends to suffer from issues with material “spring-back” and hence products created using this method tend not to exhibit the desired dimensional accuracy, resulting in a sub-optimal bond between the main body and the contact face.

Another method used for joining the main body to the contact face involves providing the contact face in two section before welding the two components together. However, this method can lead to issues with distortion and hence the dimensional accuracy of the finished product is again less than optimal.

It is therefore an aim of the present invention to address at least one of the aforementioned problems.

SUMMARY OF THE INVENTION

A first aspect of the invention provides a method of manufacturing a conductor rail comprising the steps of providing a main body of the conductor rail, providing a cap to be received onto the main body, performing a first forming operation in which the cap is plastically deformed to obtain a desired pre-form shape, placing the cap onto the main body and performing a second forming operation in which the cap is plastically deformed about the main body to create a mechanical bond between the main body and the cap.

Advantageously, performing a first forming operation wherein the cap is deformed to obtain a desired pre-form shape helps to reduce material “spring-back” and hence a closer contact-to- contact bond between the main body and the cap can be achieved, which subsequently helps to improve the conductivity of the final conductor rail product.

Furthermore, since the method of the first aspect of the invention is a non-fusion process, the conductor rail does not suffer from issues with distortion and is able to achieve an improved surface finish when compared with fusion processes, without the need for any subsequent surface finishing treatments.

In some embodiments, the method may comprise deforming the cap to obtain a pre-formed shape substantially corresponding to the shape of the main body.

Advantageously, forming the cap to obtain a pre-formed shape substantially corresponding to the shape of the main body further helps to reduce “spring-back” of the cap, and hence a closer contact-to-contact bond between the main body and the cap can be achieved.

In some embodiments, the method may comprise deforming the cap to obtain a substantially C-shaped pre-form, the C-shaped pre-form comprising a base portion, configured to interface with an upper surface of the main body, and a pair of legs configured to be plastically deformed around a head portion of the main body.

Advantageously, forming the cap to obtain a substantially C-shaped pre-form further helps to reduce “spring-back” of the cap, and hence a closer bond between the main body and the cap can be achieved.

In some embodiments, the legs of the cap may be angled relative to the base portion.

Preferably, the respective angles formed between the base portion of the cap and each leg respectively may be in the range of 80° to 90°.

Advantageously, this feature helps provide for more easy application of the cap onto the main body. In some embodiments, the base portion of the cap may comprise a pair of angled surfaces.

Preferably, the surfaces of the base portion may be angled in the range of 1 ° to 5°.

More preferably, the surfaces of the base portion may be angled in the range of 1 ° to 2°.

In some embodiments, the method may comprise roll forming the cap to achieve the desired pre-form shape.

Advantageously, the use of a roll forming process to produce the cap pre-form allows the cap to be elastically deformed more rapidly than is obtainable using other methods, and therefore processing efficiency is improved.

In some embodiments, the method may comprise roll forming the cap about the main body of the conductor rail.

Advantageously, the use of a roll forming process helps to provide a mechanical bond between the main body and the contact face exhibiting improved contact resistance.

In some embodiments, the method may comprise applying a force to the cap and to the main body, wherein the applied force is greater than a yield strength of the cap and wherein the applied force is less than a yield strength of the main body.

Advantageously, using such a force helps to ensure that sufficient plastic deformation is achieved at the cap without causing damage to the main body of the conductor rail during the manufacturing process.

In some embodiments, the first forming operation may comprise a multi-pass forming operation.

In some embodiments, the second forming operation may comprise a multi-pass forming operation.

Advantageously, performing the first and/or second forming operations as multi-pass forming operations helps to further reduce “spring-back” of the material. In each pass the force applied may be variable and sufficient to plastically deform the cap without deforming the main body when the cap is placed on the main body.

In some embodiments, the step of creating a mechanical bond between the main body and the cap may comprise the second forming operation only.

Advantageously, this method enables the formation of a mechanical bond between the main body and the cap in a single step, thereby helping to improve processing efficiency.

In some embodiments, the second forming operation may comprise bending the legs of the cap such that the respective angles formed between the base portion of the cap and each leg respectively, after the second forming operation, may be in the range of 40° to 50°.

In some embodiments, the cap may comprise a first material and the main body may comprise a second material, different to the first material.

In some embodiments, the material of the main body may be softer than the material of the cap.

In some embodiments, the main body may have a resistance in the range of 1 to 20 mQ/km.

In some embodiments, the main body may have a resistance in the range of 4 to 18 mQ/km.

In some embodiments, the main body may have a resistance in the range of 7 to 10 mQ/km.

In some embodiments, the main body may have a resistance of approximately 7 mQ/km.

In some embodiments, the conductor rail may comprise an interface between the main body and the cap.

In some embodiments, a resistance at said interface may be in the range of 5 to 60 pQ.

In some embodiments, a resistance at said interface may be in the range of 5 to 15 pQ.

In some embodiments, a resistance at said interface may be in the range of 10 to 15 pQ. Advantageously, lower interface resistances help to reduce the amount of electrical wear experienced by the conductor rail.

In some embodiments the cap may have a tensile strength of at least 400 MPa.

In some embodiments, the cap may have a tensile strength in the range of 400 and 600 MPa.

In some embodiments, the cap may be metallic.

In some embodiments, the cap may comprise steel.

In some embodiments, the main body may be metallic.

In some embodiments, the main body may comprise aluminium.

In some embodiments, the cap may be provided as a single piece.

In some embodiments, the method steps a) to e) are performed sequentially.

In some embodiments, step d) is performed prior to steps c) and e).

In other words, the cap may be placed on the main body prior to undergoing the first and second forming operations.

A second aspect of the invention provides a body for a conductor rail comprising a base portion, an intermediate stem portion, extending substantially perpendicularly from the base and a head portion, located on top of the intermediate stem portion, wherein the head portion comprises a substantially flat upper surface, such that no recesses are present at the upper surface of the head portion, and a pair of lateral edges, the lateral edges being arranged so as to overhang the intermediate stem portion such that, upon receiving a pre-formed cap, the head portion allows the pre-formed cap to be plastically deformed about the lateral edges of the head portion so as to create a mechanical bond between the body and the pre-formed cap.

Advantageously, the body of the second aspect allows a pre-formed cap to be applied to the main body which helps to reduce material “spring-back” and hence helps to achieve a closer bond between the main body and the cap. In some embodiments, the intermediate stem portion may further comprise a pair of laterally extending projections.

Advantageously, the projections increase the cross-sectional area of the body thereby improving its conductivity.

In some embodiments, the upper surface of the head portion may comprise a pair of angled surfaces.

Advantageously, the angled surfaces allow successive rails to be joined (e.g. bolted), without requiring welding.

Preferably, the upper surface of the head portion may comprise a pair of angled surfaces angled in the range of 1 ° to 5°.

Most preferably the upper surface of the head portion may comprise a pair of angled surfaces angled in the range of 1 ° to 2°.

In some embodiments, the lateral edges of the head portion may be a pair of rounded edges.

Advantageously, the provision of rounded edges helps to further allow a pre-formed cap to be applied to the main body which helps to reduce material “spring-back” and hence helps to achieve a closer bond between the main body and the cap can be achieved.

In some embodiments, the main body may be metallic.

In some embodiments, the main body may comprise aluminium. A third aspect of the invention provides a kit of parts for manufacturing a conductor rail comprising a main body of the conductor rail and a pre-formed cap having a shape substantially corresponding to a shape of the main body, and wherein the cap is configured to be plastically deformed about the main body so as to create a mechanical bond between the main body and the cap.

Advantageously, the provision of a kit comprising a main body and a pre-formed cap helps to reduce material “spring-back” during application and hence a closer contact-to-contact bond between the main body and the cap can be achieved in the finished product.

In some embodiments, the pre-formed cap may be substantially C-shaped in cross section, comprising a base portion configured to interface with an upper surface of the main body, and a pair of legs configured to be plastically deformed around a head portion of the main body.

Advantageously, the provision of a substantially C-shaped pre-form further helps to reduce “spring-back” of the cap, and hence a closer bond between the main body and the cap can be achieved in the finished product.

In some embodiments, the legs may be angled relative to the base portion.

Preferably, the respective angles between the base portion and each leg respectively may be in the range of 80° to 90°.

Advantageously, this feature helps provide for more easy application of the cap onto the main body.

In some embodiments, the base portion may comprise a pair of angled surfaces.

Preferably, the base portion may comprise a pair of angled surfaces angled in the range of 1° to 5°.

Most preferably, the base portion may comprise a pair of angled surfaces angled in the range of 1 ° to 2°. In some embodiments, an upper surface of the main body may comprise a pair of angled surfaces.

Preferably, an upper surface of the main body may comprise a pair of angled surfaces angled in the range of 1 ° to 5°.

Most preferably, an upper surface of the main body may comprise a pair of angled surfaces angled in the range of 1 ° to 2°.

In some embodiments the cap may have a tensile strength of at least 400 MPa.

In some embodiments, the cap may be metallic.

In some embodiments, the cap may comprise steel.

In some embodiments, the main body may be metallic.

In some embodiments, the main body may comprise aluminium. In some embodiments, the cap may be provided as a single piece.

A fourth aspect of the invention provides a rail installation comprising the kit according to the third aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 A illustrates a front, cross-sectional view of a main body of a conductor rail according to an embodiment of the present invention;

Figure 1 B illustrates a perspective view of the main body illustrated in Figure 1 A;

Figure 2 illustrates a front, cross-sectional view of a pre-formed cap suitable for application to the main body illustrated in Figures 1A and 1 B;

Figure 3 illustrates a perspective view of a conductor rail comprising the main body and cap illustrated in Figures 1 and 2 respectively;

Figure 4 illustrates a front, cross-sectional view of the cap of Figure 3 in isolation;

Figure 5 illustrates a front-view of a rail installation comprising the conductor rail illustrated in Figure 3;

Figure 6 illustrates a schematic flow chart depicting a method of manufacturing the conductor rail illustrated in Figure 3; and

Figures 7A-7P illustrate a front, cross-sectional views of a variety of alternative conductor rail main body configurations suitable for use in the conductor rail according to embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

A method for manufacturing a conductor rail, according to an embodiment of the present invention, shall now be described with reference to the appended figures. A depiction of the aforementioned method is provided in Figure 6.

At a first step 101 of the method, a main body 10, which forms part of the conductor rail, is provided.

The main body 10 of the conductor rail is shown in Figures 1A and 1 B. The main body 10 is typically formed from a conductive, metallic material, such as aluminium, and is made up of a base portion 12, an intermediate stem portion 14 and a head portion 16. The resistance of the main body is generally in the range of at least 1 to 20 mQ/km. For example, in the illustrated embodiment, the main body features a resistance of approximately 7 mQ/km.

The base portion 12 is provided at a bottom end of the main body 10 and is configured to provide stability to the constituent parts of the main body 10 supported thereon.

The intermediate stem portion 14 extends upwardly from the base portion 12, substantially perpendicularly thereto, and connects the base portion 12 and the head portion 16, which is also supported at the distal end of the intermediate stem portion 14.

The intermediate stem portion 14 further comprises a pair of laterally extending projections 18, which are located towards the distal end of the intermediate stem portion 16. These projections increase the cross-sectional area of the body thereby improving its conductivity. However, it shall be appreciated that, in other embodiments, said projections may be located at any point along the intermediate stem portion or, in further alternatives, may be omitted altogether.

The head portion 16 is located on top of the intermediate stem portion 14 and comprises a substantially flat upper surface 16a. In other words, no recesses are present at the upper surface of the head portion 16, as can be seen in Figure 1 B.

The head portion 16 also comprises a pair of rounded, lateral edges 16b, 16c that are arranged so as to overhang the intermediate stem portion 14. As shall be described in greater detail at later sections of this application, the overhanging edges 16b, 16c allow a pre-formed cap 20 of the conductor rail 1 to be plastically deformed about the lateral edges 16b, 16c of the head portion 16 so as to create a mechanical bond between the main body 10 and the pre-formed cap 20.

However, whilst the main body of the illustrated embodiment is described as having rounded edges, in other embodiments it shall be appreciated that main bodies having more angular edges may alternatively be provided. The upper surface 16a of the head portion 16 further comprises a pair of shallowly angled surfaces 16d, 16e which diverge outwardly from an apex, located proximal to an axial centreline of the upper surface 16a of the head portion 16, towards the lateral edges 16b, 16c.

Typically the angled surfaces have a very shallow angle in the range of 1 ° to 5°. However, in some embodiments, the angled surfaces exhibit an even shallower angle in the range of 1 ° to 2°. It shall also be appreciated that in further alternatives, a completely flat upper surface may be provided.

Following step 101 , in which the main body 10 of the conductor rail is provided, at step 102 a corresponding cap 20 is also provided.

The cap 20 is typically provided as a single piece and is typically formed from a metallic material which is harder than that of the main body 10. For example, in the illustrated embodiment, the cap 20 comprises steel having a tensile strength of at least 400 MPa, and typically between 400 and 600 MPa, whereas the main body 10 comprises a softer material, such as aluminium.

Once the cap 20 has been provided, in step 103 the cap undergoes a first forming operation in which the cap 20 is plastically deformed to obtain a desired pre-form shape for fitting onto the main body 10 of the conductor rail.

The first forming operation is typically performed as a multi-pass operation. In other words, the cap undergoes multiple forming “runs” which incrementally deform the cap into the desired pre-form shape.

In the illustrated embodiment, the first forming operation is typically performed via a roll forming operation, so as to deform the cap 20 to a desired pre-form shape. However, in other embodiments, it shall be appreciated that other suitable methods may alternatively be used.

The pre-formed cap 20 of the conductor rail is shown in Figure 2.

As can be seen in Figure 2, the cap 20 is deformed to a pre-formed shape which substantially corresponds to the shape of the main body 10 of the conductor rail, illustrated in Figure 1A and 1 B. As such, the cap 20 of the illustrated embodiment is substantially C-shaped and comprises a base portion 22 and a pair of legs 24a, 24b extending upwardly therefrom, substantially perpendicularly to the base portion 22, and configured to be plastically deformed around the head portion 16 of the main body, as shall be described in greater detail at a later stage of this application.

As shown in Figure 2, similarly to the main body 10 shown in Figures 1A and 1 B, the base portion 22 of the cap 20 further comprises a pair of shallowly angled surfaces 22a, 22b which diverge outwardly from an apex located proximal to an axial centre-line of the base portion 22.

Typically, the angled surfaces 22a, 22b have a very shallow angle Oi, a₂ in the range of 1 ° to 5°. However, in some embodiments, the angled surfaces 22a, 22b exhibit an even shallower angle ai, a₂ in the range of 1 ° to 2°. It shall also be appreciated that in further alternatives, the base portion 22 may be completely flat.

Furthermore, as shown in the illustrated embodiment, the legs 24a, 24b of the cap 20 are typically angled relative to the base portion 22. As shown in Figure 2, the respective angles Pi, p₂, formed between the base portion 22 and each leg 24a, 24b respectively are typically in the range of 80° to 90°. This enables the pre-formed cap 20 to be more easily inserted onto the main body 10 during manufacture.

Furthermore, by forming the cap to obtain a substantially C-shaped pre-form, the illustrated embodiment is advantageously able to help reduce “spring-back” of the cap, and hence a closer bond between the main body and the cap can be achieved

Once a cap 20 having the desired pre-formed shape has been obtained, the cap 20 is applied onto the main body 10 to form the conductor rail 1 at step 104.

Then, at step 105, a second forming operation is performed in which the cap 20 is plastically deformed about the main body 10 to create a mechanical bond between the main body 10 and the cap 20.

In this manner, a conductor rail 1 can be obtained, as shown in Figure 3.

As with the first forming operation, in the illustrated embodiment, the second forming operation is also typically performed via a roll forming operation. However, in other embodiments, it shall be appreciated that other suitable methods may be used. The second forming operation may be a multi-pass operation. In other words, the cap undergoes multiple forming “runs” which incrementally form the cap into the desired shape. In each pass the force applied may be variable and sufficient to plastically deform the cap 20 without deforming the main body 10. This process is called “plastic grading”.

Advantageously, performing the forming operation as a multi-pass operation helps to reduce material “spring-back” since, when using multiple forming “runs”, the elastic memory of the cap can be more effectively overcome, which results in a more “permanently” deformed cap. This also results in a closer contact to contact surface bond between the body and the cap in the final conductor rail part obtained via the process, thereby providing improved conductivity at the interface between the body and the cap in the finished part even when the cap and the main body are of different materials.

During the second forming operation, a force is applied to the cap 20 and to the main body 10 which causes the legs 24a, 24b of the cap 20 to become plastically deformed around a head portion 16 of the main body 10, as shown in Figure 4.

The configuration of the lateral edges 16b, 16c, which overhang the intermediate stem portion 14, allows the pre-formed cap 20 to be plastically deformed about the lateral edges of the head portion so as to create a mechanical bond between the main body 10 and the pre-formed cap 20.

Furthermore, as can be seen in Figure 4, after the second forming operation, the respective angles Oi, o₂ formed between the base portion 22 and each leg 24a, 24b of the cap 20 respectively are typically in the range of 40° to 50°.

In the illustrated embodiment, the force applied during step 105 is greater than a yield strength of the cap but is less than a yield strength of the main body.

Advantageously, using a force within this range helps to ensure that sufficient plastic deformation is achieved at the cap without causing damage to the main body of the conductor rail during the manufacturing process.

Furthermore, since the method of the present invention is a non-fusion process, the present invention does not suffer from issues with distortion and is able to achieve an improved surface finish when compared with fusion processes, without the need for any subsequent surface finishing treatments. However, it shall also be appreciated that whilst in the illustrated embodiment the first forming operation is performed prior to the cap being fitted to the main body, in other embodiments, the cap may be placed on the main body prior to undergoing the first and second forming operations.

As such, in such embodiments, it shall also be appreciated the force applied to the cap during the first forming operation may also be controlled such that the force applied to the cap is greater than a yield strength of the cap but is less than a yield strength of the main body.

Once the conductor rail 1 has been manufactured, via the method described above, the conductor rail 1 can then be implemented into various rail installations.

An example of one such installation is illustrated in Figure 5.

Figure 5 shows an example of an “under running” rail installation 200 made up of a support 210 for supporting a conductor rail 1 according to the illustrated embodiment, and a negative return rail 230.

The conductor rail 1 is connected to the support 210 via an insulator 220 which is configured to isolate the support 210 from any currents that may be running through the conductor rail 1 during operation.

Whilst the rail installation illustrated in Figure 5 depicts an “under running” rail installation, it shall be appreciated that this is merely an example of a type of installation that may utilise the conductor rail of the illustrated embodiment. As such, it shall be appreciated that the conductor rail may be used in any other suitable type of rail installation, such as “top running” or “side running” rail installations.

Furthermore, it shall also be appreciated that the method and cap described above may also be used in conjunction with a variety of different main body types.

A variety of different conductor rails, utilising different main body types are illustrated in Figures 7 A to 7P. Each of the different conductor main rail body types described below features a base portion, an intermediate stem portion and a head portion and so, for the sake of conciseness, only the differences between each of the various conductor rail types shall be described below.

The conductor rail 300 illustrated in Figure 7A exhibits a relatively narrow base portion 301 , having a width of only 45mm, which is substantially narrower than the corresponding width of the head portion 303 (90.8mm). The conductor rail 300 of Figure 7A also exhibits a height of 70mm. It shall also be appreciated that the intermediate stem portion 302 of conductor rail 300 does not exhibit any laterally extending projections.

The conductor rail 310, illustrated in Figure 7B, exhibits a base portion 311 having a width of 80mm, which more closely corresponds to the width of the head portion 313 (90.8mm). The conductor rail 310 of Figure 7B is also taller than that of Figure 7A exhibiting a height of 105mm. The intermediate stem portion 312 of conductor rail 310 also does not exhibit any laterally extending projections. The conductor rail 310 of Figure 7B also features a stepped portion 314 between the intermediate stem portion 312 and the head portion 313.

The conductor rail 320, illustrated in Figure 7C, also exhibits a base portion 321 having a width of 82.5mm which also closely corresponds to the width of the head portion 323 (90.8mm). The conductor rail 320 of Figure 7C is also a similar height to that of Figure 7B, exhibiting a height of 93.4mm. The intermediate stem portion 322 of conductor rail 320 also exhibits laterally extending projections 322a, as shown in Figure 7C. The conductor rail 320 of Figure 7C also features a stepped portion 324 between the intermediate stem portion 322 and the head portion 323.

The conductor rail 330, illustrated in Figure 7D, exhibits a base portion 331 , having a width of 74.2mm, which is thinner than those of Figure 7B and 7C, but still corresponds to the width of the head portion 333 (90.8mm) more closely than that of Figure 7A. The conductor rail 330 of Figure 7D is also taller than those of Figures 7A-C exhibiting a height of 108mm. The intermediate stem portion 332 of conductor rail 330 does not exhibit any laterally extending projections. The conductor rail 330 of Figure 7D also features a stepped portion 334 between the intermediate stem portion 332 and the head portion 333.

The conductor rail 340, illustrated in Figure 7E, exhibits a base portion 341 having a width of 124mm, which is wider than that of the head portion 343 (105.5mm). The conductor rail 340 of Figure 7E exhibits a height of 103.5mm and, as with Figure 7D, the intermediate stem portion 342 of conductor rail 340 also exhibits a pair of laterally extending projections 342a located proximal to the head portion 343 at a distal end of the intermediate stem portion 342.

The conductor rail 350 illustrated in Figure 7F, similarly to Figure 7A, exhibits a base portion 351 having a width of 45mm, which is substantially narrower than the corresponding width of the head portion 353 (90.8mm). The conductor rail 350 of Figure 7F also has a similar height 70mm to that of Figure 7A and does not exhibit any laterally extending projections. The conductor rail 350 of Figure 7F also features a stepped portion 354 between the intermediate stem portion 352 and the head portion 353.

The conductor rail 360 described in Figure 7G exhibits a base portion 361 having a width of 80mm, which substantially corresponds to the width of the head portion 363 (90.8mm). The conductor rail 360 of Figure 7G exhibits a height of 105mm and, as with Figure 7D, the intermediate stem portion 362 of conductor rail 360 also exhibits a pair of laterally extending projections 362a located proximal to the head portion 363 at a distal end of the intermediate stem portion 362.

The conductor rail 370 of Figure 7H is substantially the same as that of Figure 7G. However, conductor rail 370 exhibits a slightly greater height (105.3mm) and the head portion 373 exhibits a slightly lesser width (90.4mm) than those of conductor rail 360.

Similarly, the conductor rail 380 of Figure 7I is substantially the same as that of Figure 7C. However, conductor rail 380 exhibits a slightly lesser height (92.7mm) and the head portion 383 exhibits a slightly greater width (91 ,8mm) than those of conductor rail 320.

Similarly to the conductor rail 340 of Figure 7E, the conductor rail 390 illustrated in Figure 7J exhibits a base portion 391 having a width of 124mm, which is wider than that of the head portion 393 (90.4mm). The conductor rail 390 of Figure 7J also exhibits a height of 105.2mm and, as with Figure 7E, the intermediate stem portion 392 of conductor rail 340 also exhibits a pair of laterally extending projections 392a located proximal to the head portion 393 at a distal end of the intermediate stem portion 342.

The conductor rail 400, illustrated in Figure 7K, exhibits a base portion 401 , having a width of 80mm, which closely corresponds to the width of the head portion 313 (90.8mm). The conductor rail 400 of Figure 7K is also exhibits a similar height (105mm) to that of Figure 7B, and also the intermediate stem portion 402 of conductor rail 400 also does not exhibit any laterally extending projections. The base portion 401 of conductor rail 400 also further exhibits a central notch 401 a located at a point on the base portion 401 that is co-axial with the intermediate stem portion 402.

The conductor rail 410, illustrated in Figure 7L, exhibits a base portion 411 having a width of 80mm, which closely corresponds to the width of the head portion 413 (90.4mm). The conductor rail 410 of Figure 7L exhibits a height of 104.5mm and also features a pair of laterally extending projections 412a at a distal end of the intermediate stem portion 412, proximal to the head portion 413. The laterally extending projections 412a also exhibit a tapered portion 412b that extends from the laterally extending projections 412a to the head portion 413.

The conductor rail 420 described in Figure 7M is substantially similar to that described in Figure 7G. However, conductor rail 420 exhibits a slightly greater height (105.7mm) and a slightly lesser head portion width (90.4mm) when compared to that of conductor rail 360.

Similarly to the conductor rails of Figures 7E and 7J, the conductor rail 430, illustrated in Figure 7N, exhibits a base portion 431 having a width (139.7mm) which is wider than that of the head portion 433 (90.8mm). The conductor rail 430 of Figure 7N also exhibits a height of 138.1 mm and, as with Figures 7E and 7J, the intermediate stem portion 432 of conductor rail 430 also exhibits a pair of laterally extending projections 432a located proximal to the head portion 433 at a distal end of the intermediate stem portion 432.

The conductor rail 440, illustrated in Figure 70, exhibits a base portion 441 having a width of 66.7mm, which is substantially narrower than the corresponding width of the head portion 443 (90.8mm). The conductor rail 440 of Figure 70 also exhibits a height of 101.6mm and the intermediate stem portion 442 of conductor rail 440 does not exhibit any laterally extending projections. The conductor rail 440 of Figure 70 also features a pair of stepped portions 441 a and 443a located between the intermediate stem portion 442 and the base portion 441 , and between the intermediate stem portion 442 and the head portion 443 respectively.

Finally, similarly to Figure 7N, the conductor rail of Figure 7P exhibits a base portion 451 having a width (131.6mm) which is wider than that of the head portion 453 (90.8mm). The conductor rail 450 of Figure 7P also exhibits a height of 131 ,7mm and, as with Figure 7N, the intermediate stem portion 452 of conductor rail 450 also exhibits a pair of laterally extending projections 452a located proximal to the head portion 453 at a distal end of the intermediate stem portion 452. The conductor rail 450 of Figure 7P also features a stepped portion 451 a located between the intermediate stem portion 452 and the base portion 451 . Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1 . A method of manufacturing a conductor rail comprising the steps of: a) providing a main body of the conductor rail; b) providing a cap to be received onto the main body; c) performing a first forming operation in which the cap is plastically deformed to obtain a desired pre-form shape; d) placing the cap onto the main body; and e) performing a second forming operation in which the cap is plastically deformed about the main body to create a mechanical bond between the main body and the cap.

2. The method according to claim 1 , wherein step c) comprises deforming the cap to obtain a pre-formed shape substantially corresponding to the shape of the main body.

3. The method according to claim 1 or 2, wherein step c) comprises deforming the cap to obtain a substantially C-shaped pre-form, the C-shaped pre-form comprising a base portion configured to interface with an upper surface of the main body during step d), and a pair of legs configured to be plastically deformed around a head portion of the main body during step e).

4. The method according to claim 3, wherein the legs are angled relative to the base portion, and preferably wherein the respective angles formed between the base portion and each leg respectively are in the range of 80° to 90°.

5. The method according to claim 3 or 4, wherein the base portion comprises a pair of angled surfaces, preferably wherein the surfaces of the base portion are angled in the range of 1° to 5°, and most preferably wherein the surfaces of the base portion are angled in the range of 1° to 2°.

6. The method according to any preceding claim, wherein step c) comprises roll forming the cap to achieved the desired pre-form shape, and/or wherein step e) comprises roll forming the cap about the main body of the conductor rail.

7. The method according to any preceding claim, wherein step c) and/or e) comprises applying a force to the cap and to the main body, wherein the applied force is greater than a yield strength of the cap and wherein the applied force is less than a yield strength of the main body.

8. The method according to any preceding claim, wherein the first and/or second forming operations comprises a multi-pass forming operation, preferably wherein in each pass the force applied is variable and sufficient to plastically deform the cap without deforming the main body.

9. The method according to any preceding claim, wherein the step e) of creating a mechanical bond between the main body and the cap comprises the second forming operation only.

10. The method according to any preceding claim, wherein an interface is provided between the main body and the cap, and wherein a resistance at said interface is in the range of 5 to 15 pQ.

11. A body for a conductor rail comprising: a base portion; an intermediate stem portion, extending substantially perpendicularly from the base; and a head portion, located on top of the intermediate stem portion, wherein the head portion comprises a substantially flat upper surface, such that no recesses are present at the upper surface of the head portion, and a pair of lateral edges, the lateral edges being arranged so as to overhang the intermediate stem portion such that, upon receiving a pre-formed cap, the head portion allows the pre-formed cap to be plastically deformed about the lateral edges of the head portion so as to create a mechanical bond between the body and the pre-formed cap.

12. The body according to claim 1 1 , wherein the intermediate stem portion further comprises a pair of laterally extending projections.

13. The body according to claim 11 or 12, wherein the upper surface of the head portion comprises a pair of angled surfaces, preferably wherein the surfaces of the head portion are angled in the range of 1° to 5°, and most preferably wherein the surfaces of the head portion are angled in the range of 1 ° to 2°.

14. The body according to any of claims 11 to 13, wherein the lateral edges of the head portion are a pair of rounded edges.

15. A kit of parts for manufacturing a conductor rail comprising: a main body of the conductor rail; and a pre-formed cap having a shape substantially corresponding to a shape of the main body, and wherein the cap is configured to be plastically deformed about the main body so as to create a mechanical bond between the main body and the cap.

16. The kit according to claim 15, wherein the pre-formed cap is substantially C- shaped in cross section, comprising a base portion configured to interface with an upper surface of the main body, and a pair of legs configured to be plastically deformed around a head portion of the main body.

17. The kit according to claim 16, wherein the legs are angled relative to the base portion, and preferably wherein the respective angles between the base portion and each leg respectively are in the range of 80° to 90°.

18. The kit according to claim 16 or 17, wherein the base portion comprises a pair of angled surfaces, preferably wherein the surfaces of the base portion are angled in the range of 1° to 5°, and most preferably wherein the surfaces of the base portion are angled in the range of 1 ° to 2°.

19. The kit according to claim 18, wherein an upper surface of the main body comprises a pair of angled surfaces, preferably wherein the surfaces of the main body are angled in the range of 1° to 5°, and most preferably wherein the surfaces of the main body are angled in the range of 1° to 2°.

20. The kit according to any of claims 15 to 19, wherein the material of the main body is softer than the material of the cap, and preferably wherein the cap and the main body are metallic. 22

21. The kit according to any of claims 15 to 20, wherein the main body has a resistance in the range of 7 to 10 mQ/km, and preferably wherein the main body has a resistance of approximately 7 mQ/km.

22. The kit according to any of claims 15 to 21 , wherein the cap has a tensile strength of at least 400 Mpa, and preferably in the range of 400 to 600 Mpa.

23. The kit according to any of claims 15 to 22, wherein the cap comprises a first material and wherein the main body comprises a second material, different to the first material, and preferably wherein the main body comprises aluminium and the cap comprises steel.

24. The kit according to any of claims 15 to 23, wherein the cap is provided as a single piece.

25. A rail installation comprising the kit according to any of claims 15 to 24.