GB2318377A - Tramway - Google Patents

Abstract

A tramway comprises twin rails (8,10) each rail being composite, comprising an inner rail member (8 a ,8 b ;10 a ,10 b ) and a plurality of spacer members (12) secured between the rail members at spaced intervals. The tramway comprises a plurality of spacer members (12) between adjacent pairs of rail members, and tie bar assemblies extending between the rails, operative to hold the two rail members in a desired relationship, and the rails a desired distance apart.

Description

Title: Tramway Description of Invention This invention is concerned with improvements relating to tramways.

Unlike tracks for trains, it is necessary for tracks for trams to be provided with rails having an elongate groove or channel which is bounded on both sides to allow a road surface to be made up to the edge of the track. Thus conventionally a tramway track comprising an elongate rail provided with a channel in its upper surface.

Additionally since the loading of the rail is applied direct to the substrate, as distinct from the use of sleepers, the rail is conventionally provided with a base flange having an extensive lower face, to transmit loading over a relatively wide area.

Further, to improve the stability of the track, it is conventional, particularly on busy thoroughfares, to lay the rails on a bed of concrete.

Thus the laying and repair of tramways is expensive, and constitutes one of the main obstacles to the use of trams in urban areas, and it is one of the various objects of this invention to provide a tramway, and a method of laying down a tramway, which significantly reduces the expense of the utilisation of trams in urban areas.

According to this invention there is provided a tramway comprising a) first and second rails, each rail comprising inner and outer rail members; b) spacer members between said inner and outer rail members; and c) tie bar means extending between the rails which is operative to hold the rail members in a desired relationship, and the rails a desired distance apart.

By the use of two rail members, components of smaller cross section may be utilised providing for a lower manufacturing cost and greater convenience of transportation and handling. Additionally the base loading provided by each rail may be accommodated by base flanges of each rail member.

Preferably the two rail members provide a gap for the flanges of the wheels of the tram, and preferably one only of the rail members provides the running surface.

Preferably the tie bar means holds the two rail members in firm abutment with the spacer members, and preferably in abutting relationship.

Preferably the two rail members are of the same design, further reducing costs and assisting assembly.

Preferably the rail members each comprise elongate channels defined by the head of the rail member, the vertical flange thereof and the base flange, and preferably the spacer members are so shaped as to be a snug fit within said channels between two adjacent rail members.

Preferably the tie bar means is so constructed as to enable the rail members of each rail to be secured firmly together, and to provide a relatively rigid assembly.

Thus preferably the tie bar means comprises a plurality of tie bar assemblies, each comprising at opposite ends screw threaded means operative to secure the two rail members together onto the spacer members, and a spacing member to retain the rails spaced apart by a desired distance.

For example the tie bar assembly may comprise a tie bar extending through apertures in the rail members (conveniently in the vertical flanges thereof) and a sleeve of a length defining the distance between the rails (specifically the desired distance between the inner faces of the vertical flanges of the two inner rail members) and locking means (e.g. nuts) engageable with the screw threaded ends to draw the two rails together onto the sleeve and, to draw each pair of rail members together onto the spacer members.

Alternatively and preferably each tie bar assembly comprises a spacing member into which, from each side thereof, bolts may be screwed to secure the two rails members together from opposite sides of the tramway and to secure the two rails to the spacing member.

In this way a tramway may be assembled and located in position for use relatively easily and relatively quickly.

Further, whilst in practice the wheels of a tram will run on one only of the rail members of each composite rail, since the rail members are identical, when excessive wear has taken place, rather than replacing the tramway, the rail assembly may be disassembled and the rail members inter changed. Further, since wear takes place primarily on one corner edge of the rail, in theory by utilising rail members which are symmetrical in the vertical plane, four combinations of assembly may be utilised to increase the life of the tramway.

Notwithstanding the fact that wear takes place primarily on one rail member only, the rigid construction of the tramway in accordance with this invention causes vertical loading to be transmitted to both rail members, and hence the spreading of the vertical load over a larger horizontal area may be achieved less expensively than has heretofore been practical.

Additionally the rail members may be shallower than has heretofore been practical, which permits the tramway to be laid down on an existing road foundation, without the necessity to cast a separate base.

Thus preferably the rail members have a depth significantly less than has therefore been used for tramway tracks, preferably less than 150mm, and indeed less than 100mm. A rail having a depth of about 90mum may conveniently be used.

In this manner a tramway in accordance with this invention may be laid without such extensive excavation of an existing road, and thtus in accordance with another aspect of this invention there is provided a method of laying a tramway involving a) providing an elongate channel in a road surface; b) providing in the channel a tramway comprising first and second rails secured together by tie bar means; c) securing the tramway to the base surface of the channel at spaced intervals; and d) infilling the area between the area between the rails.

Preferably the channel is cut into the road surface a depth of less than 200mm, preferably about 150mm. In this way the channel may be cut down to the foundation of the road, enabling the foundation to be utilised as a base for the tramway, and obviating the need to cast a separate base. However conveniently a bedding layer is laid down on the foundation, and the tramway rails are laid onto the bedding layer.

Preferably the two rails each comprise inner and outer rail members secured together, preferably with a spacer member therebetween, and preferably the tie bar means is operative to secure the two rails together at a desired distance apart, and simultaneously secure the two rail members of each rail together onto the spacer members.

There will now be given a detailed description, to be read with reference to the accompanying drawings, of a tramway, and a method of laying down a tramway, which are preferred embodiments of this invention, having been selected for the purposes of illustrating the invention by way of example.

In the accompanying drawings: FIGURE 1 is a vertical sectional view of the tramway which is the preferred embodiment of this invention; FIGURE 2 is a horizontal sectional view of the tramway shown in figure 1; FIGURE 3 is an exploded perspective view of part of the tramway, shown on an enlarged scale.

The tramway which is the preferred embodiment of this invention comprises twin rails 8, 10, each rail being composite, and being constituted of an inner rail member 8gL 8b, 103, 10 and a plurality of spacer members 12 secured between the rail members at spaced intervals.

Each rail member is identical, comprising a head 14, providing a running surface 15, a vertical flange 16, and a base flange 18 (see figure 3). Also provided in the vertical flange 16 at spaced intervals are pairs of apertures 20a, 20b The size and spacing of the apertures is similar to the size and spacing of twin bores 13a, 13b provided in each spacer member.

On each side of each rail member an elongate channel 25 is provided, being defined by an underside of the head, a side wall of the flange 16, and an upper face of the flange 18, the spacer members being provided with surface profiles which are complimentary to said channels, whereby the spacer members 12 may be snugly fitted between each pair of rail members 8 8b, 10a, lOb.

The tramway which is the preferred embodiment of this invention also comprises a plurality of tie bar means, each tie bar nieans comprising elongate spacing members 30 having at each opposite end thereof a head 32 provided by threaded bores 32a,32b, spaced apart a distance equal to the spacing between the bores 20a, 20~and 13a, 13b.

Each tie bar assembly also comprises two pair of headed bolts 36a 36b which may be passed through the bores 20a 20h of the outer rail member 8b, through the bores 13a, 13b of the spacer member 12, through the bores 20a 20b of the inner rail member 8 and inter threaded engagement with the bores 32a, 32b of the spacing member 30. By tightening up the bolts 36a 36b from both sides, the inner rail members 8 , 10a may be drawn together onto the spacing member 30, to ensure that the two rails 8 and 10 (specifically the distance between the inside faces of the vertical flanges of the inner rail members) are a desired distance apart, and simultaneously clamp the two rail members of each rail onto the spacer members 12.

In use, a gap 11 between the two rail members accommodates the wheel flange, only one of the running surfaces being operative on each rail.

Particularly by the provision of the convex outer faces of the spacer members 12, which snugly engage the elongate cavities 25 of the rail members, by tightening of the bolts 36a and 36b a rigid rail assembly may be produced by the use of the two rail members, enabling load to be transmitted easily from the running surface 15 through both flanges 18 of the two rail members onto the foundation.

In this manner a tramway may readily be assembled in position and secured for use, conveniently by the use of clamps 40 in conventional manner.

By the use of rail members which are identical, a worn tramway may be disassembled, and the load bearing rail members substituted for non loading rail bearing members, or the rail member may be reversed, enabling the load bearing surface to be provided on the opposite side of the vertical flange.

By the construction described above, a rigid rail may be provided by the use of two rail members, enabling the composite rail to be assembled on site, and enabling load to be transmitted from the bearing surplice 15 to the flanges 18 more easily, providing the capability for transmitting load over a wider area.

This, in addition to the capability of providing rail members which are shallower than has heretofore been found practical enables the tramway to be assembled in position on a existing road more speedily than has heretofore been practical.

In particular, in the preferred embodiment of providing a tramway on an urban road, as a first step a channel 50 is cut into an existing road surface, conveniently through the top course 52 thereof, which may be asphalt, to the concrete foundation 54. Since this depth will in general be greater than the height of the rail members, a suitable bedding material 55 may be laid onto the load bearing course, to obtain the desired depth. The tramway which is the preferred embodiment of the invention may then be assembled for location in the channel 15, as herein above described, allowing the space between the inner rail members 8a, 10a to be infilled by any convenient material, which may be asphalt, or block paving.

Subsequent to infilling, the space between adjacent pairs of cavities 25 provides a convenient drainage channel for surface water.

The features disclosed in the foregoing description, or the following claims, or 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 attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (18)

1 A tramway comprising; a) first and second rails, each rail comprising inner and outer rail members; b) spacer members between the inner and outer rail members; and c) tie bar means extending between the rails which is operative to hold the rail members in a desired relationship, and the rails a desired distance apart.

2 A tramway according to Claim l wherein the two rail members provide a gap for the flanges ofthe wheels of a tram.

3 A tramway according to Claim 2 wherein one only of the rail members provides a running surface.

4 A tramway according to any one of the preceding claims wherein the tie bar means holds the rail members in firm abutrnent with the spacer members.

5 A tramway according to any one of the preceding claims wherein the two rail members are of the same design.

6 A tramway according to any one of the preceding claims wherein the rail members each comprise elongate channels defined by a head of the rail member, the vertical flange thereof and the base member.

7 A tramway according to Claim 6 wherein the spacer members are so shaped as to be a snug fit within said channels between two adjacent rail members.

8 A tramway according to any one of the preceding claims wherein the tie bar means is so constructed as to enable the rail members of each rail to be secured together as a relatively rigid assembly.

9 A tramway according to any one of the preceding claims wherein the tie bar means comprises a plurality of tie bar assemblies, each comprising at opposite ends screw threaded means operative to secure the two rail members together onto the spacer members, and a spacing member to retain the rails spaced apart at a desired distance.

10 A tramway according to Claim 9 wherein the tie bar assembly comprises a tie bar extending through apertures in the rail members and a sleeve of a length defining the distance between the rails and locking means engageable with the screw threaded ends to draw the two rails together onto the sleeve, and to draw each pair of rail members together onto the spacer members.

11 A tramway according to Claim 9 wherein each tie bar assembly comprises a spacing member onto which, from each side thereof, bolts may be screwed to secure the two rail members together from opposite sides of the tramway and to secure the two rails to the spacing member.

12 A tramway according to any one of the preceding claims wherein the rail members have a depth of less than 150mm, preferably less than 100mm.

13 A method of laying a tramway involving the steps; a) providing an elongate channel in a road surface; b) providing in the channel a tramway comprising first and second rails secured together by tie bar means; c) securing the tramway to the base surface of the channel at spaced intervals; and d) infilling the area between the rails.

14 A method according to Claim 13 wherein the channel is cut into the road surface to a depth of less than 200mm, preferably about 150mum.

15 A method according to one of Claims 13 and 14 wherein the two rails each comprise inner and outer rail members secured together.

16 A tramway constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

17 A method of laying a tramway when carried out substantially as hereinbefore described with reference to the accompanying drawings.

18 Any novel feature or any combination of features hereinbefore described and/or shown in the accompanying drawings.