GB2495763A - Railway sleeper having a channel - Google Patents

Abstract

A railway sleeper comprises an elongate member 1, preferably of plastics material, having two side faces. Along at least one side face there is provided an outwardly facing open channel 19 extending longitudinally of the elongate member from adjacent one end to adjacent the other end. A cable 25, 26 can be placed laterally into the channel. A removable cover plate 20 can be secured over the channel to cover the cable. The cover plate may be secured by a snap fit mechanism or fixing screws. A plastics liner insert may be located in the channel. Also claimed is: A track installation comprising a pair of rails, a plurality of sleepers and clips securing the rails to the sleepers, at least one of the sleepers being a sleeper as described; and a method of installing such a track installation.

Description

Railway Sleeper This invention relates to a railway sleeper, sometimes referred to as a "crosstie" or "tie" for short.

S

A railway sleeper extends transversely underneath a pair of rails, which are held to the sleeper by appropriate rail clips. The sleeper rests on a bed of ballast.

Traditionally, railway sleepers have been of timber but more recently sleepers have been constructed from reinforced concrete, steel and plastic materials. It has been proposed that a conduit may be provided inside a sleeper, extending one end of the sleeper to the other. Cables can then be passed through the conduit, extending across the track. An example of such an arrangement is disclosed in United States Patent 6,604,689 which discloses a steel sleeper with a conduit through which a communications cable can be passed.

GB 2473729 A discloses a railway sleeper in the form of an elongate member of plastics material having two ends, two side faces, a top surface and a bottom surface. The reinforced plastics material in the sleepers disclosed may be reinforced, for example with glass fibre or carbon fibre, and may include a filler.

Viewed from one aspect the present invention provides a railway sleeper, wherein along at least one side face there is provided an outwardly facing open channel extending longitudinally of the sleeper from adjacent one end to adjacent the other end.

The channel can be used to accommodate cables, such as communications, signalling or power cables, which need to extend across the track, underneath the rails. This allows the cables to be safely encased in the sleeper and avoid damage from ballast tamping machines.

In some embodiments a channel is provided on both side faces of the sleeper.

The channel may be provided with a removable cover plate to provide further protection to the cable or cables located within the channel. The cover plate may be held in place by a snap fit mechanism, and optionally with fixing screws also.

Alternatively, there may be provided longitudinally extending upper and lower grooves, into which a cover plate can be slid from one end of the sleeper.

Because the cover plate is removable to reveal the channel, a cable can be S inserted laterally into the channel and the cover plate replaced. It is unnecessary to disconnect the cable so that a free end can be fed through a tubular conduit of the type disclosed in United States Patent 6,604,689.

The cover plate may be of a plastics material.

A snap fit may be provided by engagement of one or more portions of the cover plate with corresponding portion(s) formed on the elongate member, which is of plastics material. Alternatively, a longitudinally extending plastics insert may be located in the channel and the snap I it may be provided by engagement of one or more portions of the cover plate with corresponding portion(s) formed on the liner.

A track installation may include a plurality of sleepers which do not have the channel in a side face, in which case a sleeper with a channel is used when desired to deal with cables. Alternatively, all of the sleepers are provided with a channel in a side face; and a cover plate -or a liner and a cover plate -are used on those sleepers which are to be used with one or more cables. If cover plates are fitted directly on to the body of a sleeper, they may be provided separately for use when desired. If an insert is provided in a channel, the insert may be inserted before supply of a sleeper to be used the accept cables, or may be inserted on site when needed. A cover plate would also be supplied.

The body of the sleeper may be constructed from recycled plastics material. It may be a composite plastic material, which may include fibres, filaments, wires or the like. The composite plastic material may be made from mixtures of materials, such as plastic, rubber from used tyres, waste fibreglass and the like. The plastic material forming the body of the sleeper is preferably insulating.

The use of electrically insulating plastic or plastic composite material for constructing the main body of a sleeper is advantageous for a number of reasons.

The use of electrically insulating material has advantages when used with signalling track circuits. In some cases these circuits rely on the two running rails being electrically isolated from each other. Steel is a conductor so for this to be achieved additional insulators have to be fitted -which is not the case with an insulating plastic sleeper. Secondly, in some railway configurations a third rail is used to S provide electricity for motive power. Again this needs to be isolated from the running rail so a plastic sleeper, being an insuiator, provides an advantage.

Additionally, steel is prone to corrosion and in particular electrolytic corrosion.

Electrolytic corrosion is caused by electrical current, often a leaked, stray or induced current, in the steel component. Corrosion is accelerated by the creation of electrochemical cells in which the steel acts as an anode and is attacked. This type of corrosion is known to be a problem on railways, particularly those using DC (direct current) traction systems. The plastic material used to form the body of the sleeper is not susceptible to corrosion and in particular, as it is an insulator, is not susceptible to electrolytic corrosion.

The invention also extends to a track installation comprising a pair of rails; a plurality of sleepers extending transversely underneath, and supporting, the rails; clips securing the rails to the sleepers; and at least one of the sleepers being in the form of an elongate member of plastics material having two ends, two side faces, a top surface and a bottom surface, wherein along at least one side face there is provided an outwardly facing open channel extending longitudinally of the sleeper from adjacent one end to adjacent the other end. This sleeper may have all of the features of the sleeper described above, such as a removable cover plate or an insert and a removable cover plate. A cable may extend through the channel.

The invention also extends to a method of installing a railway sleeper comprising the steps of placing a placing a plurality of sleepers on a support, and attaching the sleepers to the track, wherein and at least one of the sleepers is in the form of an elongate member of plastics material having two ends, two side faces, a top surface and a bottom surface, wherein along at least one side face there is provided an outwardly facing open channel extending longitudinally of the sleeper from adjacent one end to adjacent the other end. This sleeper may have all of the features of the sleeper described above, such as a removable cover plate or an insert and a removable cover plate. A cable may extend through the channel.

Some embodiments of the invention with now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a plan view of a portion of railway track; Figure 2 is a perspective view of a sleeper in accordance with the invention; Figure 3 is a section through one side of the sleeper; Figure 4 is an enlarged view of the area A on figure 3; FigureS is a section through one side of an alternative embodiment of sleeper; Figure 6 is an enlarged view of the area B on figure 5; and Figure 7 is a section through one side of a further alternative embodiment of sleeper.

Referring now to Figure 1 there is a portion of railway track comprising a number of sleepers 1 to which are attached rails 2 by clips (not shown). The sleepers are made of a moulded composite plastics material, for example made from recycled materials. As shown in Figure 2 one of the sleepers 1 has a recess 3 along one edge, to receive cables, which is open at both ends. The recess is open laterally but is covered by a removable cover plate 4 of moulded plastics.

With reference to Figures 3 and 4, in this embodiment the recess 3 is provided with an extruded plastics insert 5, into which the cover plate 4 forms a snap fit. The upper part of the insert is formed with a grooves 6 into which a portion 7 forms a snap fit. Portion 7 is at the end of and arm 8 projecting inwardly from the front of the cover plate. A corresponding structure is provided at the lower part of the extrusion, with groove 6' receiving snap fit portion 7' at the end of arm 8'. There is also the option of using screws to improve the security of the snap fit, there being a recessed area of the sleeper and the insert and portions 9 and 9' provided with V grooves to locate the screw position. By was of example only, in this embodiment the recess 3 can receive two 37 mm diameter cables.

Figures 5 and 6 show an alternative embodiment of a sleeper 20, of moulded composite plastics material. This is provided with a longitudinally extending recess 11 along one side face, which is open at both ends. The recess is open laterally but S is provided with a cover plate 12 of moulded plastics. However, in this embodiment there is no insert in the recess and the cover plate forms a snap fit directly with the basic material of the sleeper. At the upper end of the recess 11, there is provided a groove 13 which receives a snap fit portion 14 at the end of an arm 15 projecting inwardly from the front of the cover plate. Above this, the sleeper is provided with a further groove 16 which receives a safe return of the cover plate. At the lower end the construction corresponds, with groove 23' receiving snap fit portion 14', which is at the end of arm 15'. There is an additional groove 17' receiving safe return 17'.

Whilst this embodiment is intended to rely on the snap fit only, it would be possible to adapt it use screws also.

Figure 7 shows an alternative embodiment of a sleeper 18, of moulded composite plastics material. This is provided with a longitudinally extending recess 19 along one side face, which is open at both ends. This recess 19 is open laterally but is provided with a moulded plastics cover plate 12. Along its upper edge, the cover plate 20 is provided with an inwardly recessed flange 21, which is received in a groove 22 in the body of the sleeper 18. Along its lower edge, the cover plate 20 is provided with an inwardly recessed flange 23, which is received in a groove 24 in the body of the sleeper 18. The cover plate can thus be slid into place, and removed from, from either end of the sleeper 18. One end of each groove 22 and 24 may be blanked off so that the cover plate 20 can only be inserted and removed from one end. Inside the recess 19 are shown two cables 25 and 26. Instead of the cover plate shown, which has inwardly recessed flanges 21 and 23, there could be aa cover plate which is simply a flat plate of plastic, slid into grooves 22 and 24. In that the cover plate will be recessed somewhat from the side face of the sleeper.

Claims (1)

1. <claim-text>CLAIMS1. A railway sleeper comprising an elongate member having two side faces, wherein along at least one side face there is provided an outwardly facing open channel extending longitudinally of the elongate member from adjacent one end to adjacent the other end.</claim-text> <claim-text>2. A railway sleeper as claimed in claim 1, wherein the channel is provided with a removable cover plate.</claim-text> <claim-text>3. A railway sleeper as claimed in claim 2, wherein the cover plate is held in place by a snap fit mechanism.</claim-text> <claim-text>4. A railway sleeper as claimed in claim 3, wherein the snap fit is provided by (\J 15 engagement of one or more portions of the cover plate with one or more corresponding portions formed on the elongate member.</claim-text> <claim-text>5. A railway sleeper as claimed in claim 3, wherein a longitudinally extending plastics liner insert is located in the channel and the snap fit is provided by engagement of one or more portions of the cover plate with one or more corresponding portions formed on the liner insert.</claim-text> <claim-text>6. A railway sleeper as claimed in claim 2, wherein there are provided longitudinally extending upper and lower grooves, into which the cover plate can be slid from one end of the sleeper.7. A railway sleeper as claimed in any of claims 2 to 6, wherein the cover plate is held in place with fixing screws.6. A railway sleeper as claimed in any of claims 2 to 7, wherein the cover plate is of a plastics material.</claim-text> <claim-text>7. A railway sleeper as claimed in any preceding claim, wherein a channel is provided on both side faces of the sleeper.9. A sleeper as claimed in any preceding claim, wherein the elongate member is made from plastics material.10. A sleeper as claimed in claim 9, wherein the elongate member is made from S recycled plastics material.11. A sleeper as claimed in claim 9 or 10, wherein the elongate member is made from a composite plastics material.12. A sleeper as claimed in claim 9, 10 or 11, wherein the elongate member is made from an electrically insulating plastics material.13. A track installation comprising a pair of rails; a plurality of sleepers extending transversely underneath, and supporting, the rails; and clips securing the (\J 15 rails to the sleepers; wherein at least one of the sleepers is a sleeper as claimed in any of claims ito 12.14. A track installation as claimed in claim 13, wherein a cable extends through the channel of at least one of the sleepers which is as claimed in any of claims 1 to 12.15. A track installation as claimed in claim 13 or 14, wherein the sleepers which are not as claimed in any of claims 1 to 12 are of plastics material.16. A track installation as claimed in claim 15, wherein the sleepers which are not as claimed in any of claims 1 to 12 are of recycled plastics material.17. A track installation as claimed in claim 15 or 16, wherein the sleepers which are not as claimed in any of claims 1 to 12 are of a composite plastics material.18. A method of installing a track installation comprising the steps of placing a placing a plurality of sleepers on a support, and attaching a pair of rails to the sleepers, wherein at least one of the sleepers is a sleeper as claimed in any of claims ito 12.19. A method as claimed in claim 18, comprising the step of placing a cable laterally into the channel of at least one of the sleepers which is as claimed in any of claims ito 12.20. A method as claimed in claim 18 or 19, wherein the sleepers which are not as claimed in any of claims 1 to 12 are of plastics material. (4 r 0)</claim-text>