Rail system

Abstract

A rail system comprising an elongate ducting trough (22) located, for example, generally centrally along a swept path (20). The ducting trough (22) comprises a plurality of trough sections, each defining a pair of channels (24, 26) for housing electrical cables (not shown). The system further comprises a pair of rails (34) positioned, for example, on either side of the ducting trough (22) and running substantially parallel thereto. The rails (34) and the ducting trough (22) are substantially in the same plane and/or at substantially the same level.

Description

This invention relates to a rail system and, more particularly, a method and apparatus for providing a rail system, such as (but not exclusive) a street-running tram or light rail system.

FIG. 1 shows the prior art. Traditionally, in order to provide a trackform for rails 34, it is necessary to excavate street 10 (between footpaths 12 having kerb 14) to provide an envelope to contain the sub structure for the trackform and the required High and Low voltage duct banks (often referred to as conduits). The width of this envelope is a function of the width of the rail vehicle whilst moving (Developed Kinematic Envelope), the track geometry (vertical, horizontal and cant) and the High and Low voltage duct bank configurations. The excavation depth is typically around 1200 mm to 1500 mm (vertically) below existing road level.

At around the above-mentioned depth (typically 1200 mm to 1500 mm below existing road level) the High and Low voltage duct banks, 24, 26 are provided, typically either side and outside the trackform. Historically, these duct banks are at greater vertical depth than the rails 34 and would come no closer than 600 mm (vertically) to the finished top of rail level. The High and Low voltage duct banks 24, 26 are required to ensure the rail system can operate.

A suitable sub-grade material 20 (to comply with Highways agency or local government specifications for example) is then placed between the ducts 24, 26 if required and a flush surface is provided typically around 500-600 mm below the finished top of rail level.

In accordance with a first aspect of the present invention, there is provided a rail system, comprising an elongate ducting trough located along a swept path, said ducting trough being for housing electrical cables, and at least one rail on which a train or tram runs, said rail being positioned alongside and generally parallel to said ducting trough.

Also in accordance with the first aspect of the present invention, there is provided a method of providing a rail system, comprising the steps of providing an elongate ducting trough along a swept path, said ducting trough being for housing electrical cables, and providing at least one rail alongside and generally parallel to said ducting trough.

Beneficially, the ducting trough and the at least one rail are in substantially the same plane and/or at substantially the same level, in use.

The ducting trough may, for example, be positioned substantially centrally (with one or more rails being positioned to the side thereof) or it may be positioned at or adjacent the side of the swept path.

In accordance with a second aspect of the present invention, there is provided a trough section for use in constructing a rail system, said trough section defining at least one channel for housing electrical cables and being adapted to be positioned generally centrally within a swept path alongside and generally parallel to said at least one rail.

Preferably, the trough section has a built-in radius at one or more ends such that two or more trough sections may be positioned adjacent to each other and fit snugly together, even if they are being placed around a curve or bend. The or each trough preferably defines at least two channels, one for housing low voltage cables and the other for housing high voltage cables.

The swept path of the rail system can be relatively shallow, say around 500 mm, or so, such that the number of utilities affected by the excavation can be minimised, if not eliminated altogether. Means, such as a cantilevered structure, may be provided to carry a feeder pole, such that the need for deep excavation for this purpose is also eliminated.

The ducting trough, or each trough section, is beneficially formed of reinforced concrete. Some sections may comprise unitary structures, whereas one or more others may be provided with an opening at the top having a removable cover, thereby to allow access to the electrical cables housed within the channels. In one embodiment of the present invention, a trough having a removable cover is placed at spaced-apart intervals (say every 100m or so) along the length of the rail system.

An exemplary embodiment of the present invention provides a simplified construction method by providing conduits at a high level, which also provide temporary lateral support to the rails during the construction process.

According to another aspect of this invention, there is provided a rail system comprising a ducting trough or support member and at least one rail; the rail being positioned along side the ducting trough or support member.

Preferably the rail and ducting trough or support member are positioned at substantially the same depth. Beneficially, the rail and the ducting trough or support member are of substantially the same height and/or in substantially the same plane, in use.

Also according to this invention there is provided a trough or support section for use in constructing a rail system, the trough or support section having either securing means (or allowing securing means to be attached to it) or defining at least one channel for housing electrical and mechanical cables and equipment and being adapted to be positioned generally along side at least one rail.

Preferably the securing means is a thread, although this is not essential.

It is also preferable that the trough or support section has built in radii at one or more ends such that two or more trough sections may be positioned adjacent to each other and fit snugly together in both the horizontal and vertical planes. (This depends on the construction method, the above is more relevant to pre-cast or “off-site” manufacture, however, cast “in-situ” solutions are equally applicable).

More preferably the trough or support section defines at least two channels, one for housing low voltage cables and the other for housing high voltage cables.

Even more preferably the trough or support section is at least partially formed of reinforced concrete, composites, resin, or polymer. And it may comprise a substantially unitary structure or a substantially solid structure.

Preferably the trough or support section includes electrical cables housed within the channels.

Preferably the trough or support section comprises at least one bar extending outward from the section.

Preferably the rail system has a ducting trough or support member comprising one or more trough or support sections.

Preferably the rail system comprises a depth of construction which is relatively shallow.

Preferably the rail system includes means for carrying electrical or mechanical equipment.

One means of carrying electrical and mechanical equipment is a cantilever structure.

Preferably the rail system has ducting trough or support member comprising a combination of trough or support sections.

Preferably the rail system has ducting trough or support member having one or more removable covers.

More preferably the rail system has one or more removable covers which are spaced apart at intervals along the length of the ducting trough or support member.

Also according to the invention there is provided a method of constructing a rail system, comprising the steps or providing an elongated ducting trough or support member substantially positioned along side at least one rail.

Preferably the method of constructing a rail system comprises the steps of laying an elongated ducting trough or support member, then laying a sub-base, positioning at least one rail substantially along side the ducting trough and then pouring a concrete slab.

More preferably the at least one rail and ducting trough or support member are positioned at substantially the same depth. Beneficially, the rail and the ducting trough or support member are of substantially the same height and/or in substantially the same plane, in use.

Preferably the method of constructing a rail system comprises the additional step of securing a gauge support frame to the ducting trough in order to position at least one rail.

These and other aspects of the present invention will be apparent from, and elucidated with reference to the embodiment described herein.

An embodiment of the present invention will now be described by way of example only, and with reference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of a rail system according to the prior art;

FIGS. 2A-2F are schematic cross-sectional views of the various stages involved in providing a rail system according to an exemplary embodiment of the present invention;

FIG. 3 is a schematic plan view of a rail system according to an exemplary embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a rail system according to an exemplary embodiment of the present invention;

FIG. 5 is a perspective view of a trough section according to an exemplary embodiment of the present invention;

FIG. 6 is a side view of the trough section of FIG. 5;

FIG. 7 is a side view of an alternative trough section;

FIG. 8 is a schematic cross-sectional view of the trough of FIG. 5;

FIG. 9 is schematic plan view of a plurality of trough sections fitted together along a bend;

FIG. 10 is a schematic cross-sectional view of the trough section of FIG. 5, illustrating the reinforcement features thereof;

FIG. 11 is a schematic cross-sectional view of a rail system according to an exemplary embodiment of the present invention;

FIG. 12 is a schematic side view of a stray current isolation joint;

FIG. 13 is a perspective view of part of a drainage box for use in the system of FIG. 11;

FIG. 14 is a schematic cross-sectional view of a rail system according to an exemplary embodiment of the invention, illustrating a trough section having a removable cover;

FIG. 14A is a schematic perspective view illustrating the cover of the trough section of FIG. 14;

FIG. 15 is a schematic plan view of the rail system of FIG. 14;

FIG. 16 is a schematic perspective view illustrating the cantilevered structure of a feeder pole base, provided off the track of a rail system according to an exemplary embodiment of the present invention; and

FIG. 17 is a schematic cross-sectional view of a rail system according to an exemplary embodiment of the invention, illustrating the connection of the high voltage cables to a feeder pole.

Referring to FIGS. 2A to 2I inclusive of the drawings, an overview of a preferred method of constructing a rail system according to an exemplary embodiment of the invention will now be given.

The trackform design is based on a single poured Continuously Reinforced Concrete Pavement (CRCP) design conforming with the Highways Agency Design Manual for Roads and Bridges (DMRB). However, other trackform construction methods can equally be used, for example, Jointed Concrete Pavements (JCP), Continuously Reinforced Concrete Roads (CRCR), un-reinforced trackforms, concrete bearers cast into a trackform, glass fibre (or other fibre) reinforced, or ballasted track.

As shown in FIG. 2A, a typical street comprises a road section 10 and footpaths 12 running either side of the road section 10. Each footpath 12 is generally defined by a kerb 14. Drainage gulleys 16 are provided at the interface between the road section 10 and the kerb 14. The drainage gulleys 16 normally connect into respective carrier drains 18 running longitudinally with the street.

With reference to FIG. 2B, the first step of the method would generally involve excavating a section of the road 10. This excavation depth would typically be 500 mm deep and uniform across the width of the trackform only. The width is a function of the type of rail vehicle, track geometry and other constraints depending upon uniquenesses of the particular location. However, for the “plain line” case, 500 mm is a typical figure.

The 500 mm depth would be “saw cut” vertically into the existing highway surface and material to this depth is excavated between the vertical “saw cuts”.

It will be appreciated that historically, in order to provide sufficient formation stiffness, the Californian Bearing Ratio (CBR) percentage, as outlined in the Highways Agency DMRB publications of 15% or higher should be attained. If CBR of 15% or higher is not attained, then capping layers shall be provided complying with the DMRB as described above.

If CBR's of 15% or higher are attained the bottom of formation will be compacted with suitable construction plant.

It should be noted that this invention does not rely on CBR of 15% being achieved; CBR's can be lower, say minimum 5% due to the load path created by a concrete trackform, or other trackforms outlined earlier.

Once the material has been excavated, a ducting trough 22 is positioned along the centreline of the excavation, see FIG. 2C. It should be noted however, that the ducting trough 22 may also be placed to either side of the excavation.

The structure, formation and features of the ducting trough 22 will be described in more detail below. However, it will be noted, that for this example, the ducting trough 22 defines two parallel channels 24, 26, one for the Low voltage cables and the other for the High voltage cables. Other cables can also be carried by these apertures.

Referring to FIG. 2D of the drawings, the next step of the process involves the placing of a layer of sub base material 27 (of say 150 mm depth, fitting flush up to the “saw cut” highway on one side and the trough 22 on the other). This material will comply with the DMRB requirements, and will normally be a Cement Treated Basecourse. This material will be well compacted. Other material types may be used.

As illustrated in FIG. 2E, a first layer (the bottom layer) of steel reinforcing mesh 28 is placed on top of the sub base material 27, and welded as required for stray current collection purposes.

The rail 34 is then placed in the excavation and welded to form a continuous length to suit the site conditions. Alternatively, two channels can be formed by formwork. The channels are dimensioned to take a rail of desired section. The rail can be placed into these channels at a later time.

A top trackform reinforcement, preferably a mesh 32, rail support reinforcement 30 and any other ducting requirements for signalling, stray current collection, drainage products and pipes etc. is put in place.

Referring to FIG. 2F of the drawings, each pair of rails 34, forming a track is supported in this example by the “top down” rail construction method by using Gauge Support Frames (GSF's) 36 which are stabilised laterally by fixing the GSF to a thread (see FIG. 8) cast into the troughs 22 at nominal centres (say every 500 mm for maximum flexibility).

All of the mesh 28, 30, 32 is welded together and is also used as the primary stray current collection system. At this time the mesh is spaced 28, 30, 32 as required, to provide reinforcement cover. It will be appreciated that the rails (or formed channels for the rails) will be checked for line and level at this time.

As can be seen, the GSF's 36 each have a pair of prongs 40 which extend into the and co-operate with the mesh layers, whilst the rails are suspended by the GSF's. As previously mentioned all products, ducting, drainage 3tc. will be set to position at this time, prior to pouring the trackform concrete.

This construction method (i.e. GSF) is state of the art, but a conventional process for trackwork specialists, and will therefore not be described in any more detail.

The drainage boxes 31 will be linked to the existing drainage system provided by the drainage gulleys 16 and associated carrier drains 18 (as illustrated in FIG. 4).

Referring to FIG. 2G, structural concrete is then poured into the excavation up to a level 35-100 mm say below the final top of rail level, for this particular example. When the concrete has reached a required strength, usually after two to three days, the GSF's are removed and the holes left by the GSF legs 40 are filled with a non shrink grout or similar material.

Concrete shoulders 44 can then be cast level with the top of the rails. These are not essential, and could be replaced by a full width concrete finish, Pre-Cast Modular Block finish, or a bituminous surface laid adjacent to the rail.

It is often advisable to expose the aggregate contained within the concrete to attain as high a skid resistance value as is possible. It is further advisable to colour the concrete to match aesthetically the surrounding road surface, or alternatively make the rails “stand out”.

PSV values must satisfy the requirements stipulated by the DMRB and due care and attention must be given to ensure that the PSV of the different materials is as close to each other as possible, thus mitigating possible highway vehicle differential skid resistance issues.

Finally, highway “tie in” details are constructed. The reader shall note that the trackform/highway interface was “saw cut”, the highway “tie-in” details shall be kept as simple as possible, while also satisfying the requirements of the DMRB. See FIG. 2I and FIG. 4 showing an example of this detail.

The finished rail system can be seen in more detail in FIGS. 3, 4, 14, 15 and 17 of the drawings.

In the second embodiment of the invention ducting trough 22 need not provide housing of the electrical cables but utilised for construction purposes. In this embodiment the trough 22 may be a support member providing formwork or support for the GSF's as described above.

Referring to FIGS. 5 to 10 of the drawings, the ducting trough 22 will now be described in more detail. As shown, an exemplary embodiment of the ducting trough 22 according to the invention is made up of a plurality of ducting sections 50, each defining channels 24, 26 running therethrough. Each section 50 has a built-in radius at opposing ends thereof, for example, as illustrated in FIG. 6 or alternatively FIG. 7, such that the sections fit together snugly, even around bends (in both the horizontal and vertical planes), and can, therefore, be articulated as illustrated in FIG. 9.

Each trough section 50 is made of concrete, reinforced by steel mesh 52 as shown in FIG. 10. Metal bars 54 may be embedded in, and extend outward of, each section 50. Bars 54 can be used as fixities for convenient lifting or craning of each section 50 into position. A pair of threads 56, as shown in FIG. 8, may be cast into the top of each section 50 for use in stabilising the gauge support frame (as explained above). It will be appreciated that the configuration of each trough section 50 according to this exemplary embodiment of the invention provides no water paths or construction joints, such that it acts as a Faraday cage to prevent, or at least minimise, stray current.

Referring to FIGS. 14, 14A and 15, at spaced-apart intervals (say every 100 m) the trough section 50 having a removable cover 60 (or “manhole”) may be provided to enable convenient placing of, sight of and access to the cables in the channels 24, 26. In addition, this provides, for example, a convenient way for maintenance workers to measure stray current at specific points along the track. The cover 60 may comprise a reinforced concrete slab housed within a steel tray 62 which is bolted on the top of the trough section 50. The cover may be removably held in place by a number of anti-vandal bolts 64.

Referring now to FIGS. 16 and 17, the high voltage cables housed in channels 26 of the ducting trough 22 are connected to feeder poles 70 for carrying current back to the sub-station. The feeder poles 70 are provided at spaced apart intervals along the train line. A cantilevered structure 72 provided to the side of the track may be provided to carry each feeder pole 70. This eliminates the need for deep excavation for this purpose.

Referring to FIG. 3F, each pair of rails 34 is supported top down by a gauge support frame (GSF) 36 which is stabilised by a respective thread cast into the top of the trough 22. A pair of GSF's 36 are provided at spaced apart intervals along the length of track path. All of the mesh is then welded together and spaced as required. It will be appreciated that the position of the rails 34 may be needed to be checked at this stage before they are permanently fixed. As can be seen, the GSF's 36 each have a pair of prongs 40 which extend into and co-operate with the mesh layers 28,32, while the rails 34 are suspended above the bottom of the draining boxes 30 by the bracket-like members 42 at each end of the GSF 36. This is a conventional process and will not be described in any more detail.

Thus the present invention relates to a design and construction method for providing a trackform encompassing a holistic design and associated construction method, taking into consideration ease of construction, operation, maintenance and demolition.

The design and associated construction method, is a fully integrated multi-disciplinary engineering solution concerning, civil, rail, electrical and mechanical and signalling resulting in a safe, easily maintainable operational rail system.

The rail system example given here within rates to a street running (or flush paved) trackform. This is just one embodiment of the proposed rail system, and to the experienced reader skilled in the art of engineering, adaptions on this theme will become immediately evident.

The rail system is however equally applicable to all other forms of rail design and construction. These include without excluding others; segregated running, tram, metro, light rail, heavy rail, high-speed rail and freight rail system. This rail system can be applied to all aspects of rail design and construction; for example, at grade, within a tunnel, running with a highway or elevated etc.

All technical phrases referred to are well known in the United Kingdom Rail Industry, e.g. Her Majesty's Railway Inspectorate Railway Safety Principles & Guidance documentation.

An embodiment of the present invention has been described above by way of example only, and it will be appreciated by a person skilled in the art that modifications and variations may be made to the described embodiments without departing from the scope of the invention as defined by the appended claims.

Claims

1. A rail system comprising an elongate ducting trough located along a swept path, said ducting trough being for housing electrical cables, the system further comprising at least one rail on which a train or tram runs, said rail being positioned alongside and generally parallel to said ducting trough.

2. A rail system according to claim 1, wherein said ducting trough and said at least one rail are in substantially the same plane and/or at substantially the same level, in use.

3. A trough section for use in constructing a rail system according to claim 1, said trough section defining at least one channel for housing electrical cables and being adapted to be positioned within a swept path, alongside and generally parallel to said at least one rail.

4. A trough section according to claim 3, having a built-in radius at one or more ends such that two or more trough sections may be positioned adjacent to each other and fit snugly together.

5. A trough section according to claim 3, which defines at least two channels, one for housing low voltage cables and the other for housing high voltage cables.

6. A trough section according to claim 3, at least partially formed of reinforced concrete.

7. A trough section according to claim 3, comprising a substantially unitary structure.

8. A trough section according to claim 3, including electrical cables housed within the channels.

9. (canceled)

10. A rail system according to claim 1, wherein the swept path is relatively shallow.

11. A rail system according to claim 1, wherein said ducting trough is positioned generally centrally within said swept path.

12. A rail system according to claim 1, wherein said ducting trough is positioned at or adjacent the side of said swept path.

13. A rail system according to claim 1, further comprising a cantilevered structure for carrying a feeder pole.

14. A rail system according to claim 9, wherein said ducting trough comprises a combination of trough sections according to claim 7 and claim 8, respectively.

15. A rail system according to claim 14, wherein a trough section having a removable cover is placed at spaced-apart intervals along the length of the ducting trough.

16. A method of providing a rail system, comprising the steps of providing an elongate ducting trough along a swept path, said ducting trough being for housing electrical cables, and providing at least one rail alongside and generally parallel to said ducting trough.

17. A method according to claim 16, wherein said ducting trough and said at least one rail are in substantially the same plane and/or at substantially the same level.

18. A method according to claim 17, wherein said ducting trough is positioned substantially centrally within said swept path.

19. A method according to claim 17, wherein said ducting trough is positioned at or adjacent a side of said swept path.

20. A rail system comprising a ducting trough or a support member and at least one rail; the rail being positioned along side the ducting trough or support member.

21. A rail system according to claim 20, where the rail and ducting trough or support member are positioned at substantially the same depth.

22. A rail system according to claim 21, wherein said rail and ducting trough or support members are of substantially the same height and/or in substantially the same plane, in use.

23. A trough or support section for use in constructing a rail system, said trough or support section having securing means and defining at least one channel for housing electrical and mechanical cables and equipment and being adapted to be positioned generally along side at least one rail.

24. A trough or support section according to claim 23, where the securing means is a thread.

25. A trough or support section according to claim 23, having built in radii at one or more ends such that two or more trough sections may be positioned adjacent to each other and fit snugly together in both the horizontal and vertical planes.

26. A trough or support section according to claim 23 which is cast “in situ”.

27. A trough or support section according to claim 23, defining at least two channels, one for housing low voltage cables and the other for housing high voltage cables.

28. A trough or support section according to claim 23, at least partially formed of reinforced concrete, composites, resin, or polymer.

29. A trough or support section according to claim 23, comprising a substantially unitary structure.

30. A trough or support section according to claim 23, comprising a substantially solid structure.

31. A trough or support section according to claim 23, including electrical cables housed within the channels.

32. A trough or support section according to claim 23, comprising at least one bar extending outward from the section.

33. A rail system according to claim 20, wherein said ducting trough or support member comprises one or more trough or support sections according to claim 19.

34. A rail system according to claim 33, comprising a depth of construction which is relatively shallow.

35. A rail system according to claim 20, including means for carrying electrical or mechanical equipment.

36. A rail system according to claim 35, wherein the carrying means is a cantilever structure.

37. A rail system according to claim 36, wherein said ducting trough or support member comprises a combination of trough or support sections.

38. A rail system according to claim 37, wherein said ducting trough or support member has one or more removable covers.

39. A rail system according to claim 38, wherein more than one removable covers are spaced apart at intervals along the length of the ducting trough or support member.

40. A method of constructing a rail system, comprising the steps of providing an elongated ducting trough or support member substantially positioned along side at least one rail.

41. A method of constructing a rail system according to claim 40, comprising the steps of laying an elongated ducting through or support member, then laying a sub-base, positioning at least one rail substantially along side the ducting trough and then pouring a reinforced concrete slab.

42. A method of constructing a rail system according to claim 40, where the at least one rail and ducting trough or support member are positioned at substantially the same depth.

43. A method of constructing a rail system according to claim 40, further comprising the additional step of securing a gauge support frame to the ducting trough in order to position the at least one rail.