Method of installing a railway sleeper

Abstract

An existing railway line is mounted to a fresh concrete sleeper by drilling a hole through a base plate which is attached to the line. A threaded sleeve with a large head is inserted into the hole from below and a threaded shank is passed through the base plate and into the hole from above and is then engaged with the sleeve.

Description

BACKGROUND OF THE INVENTION

This invention relates to the installation of a railway sleeper particularly at a railway line turnout or crossing.

At a turnout single railway lines are split into two. At a crossing a facility is provided whereby two lines cross each other. Due to the varying effective width over which the railway lines extend a need exists for railway sleepers of variable lengths.

In a new turnout or crossing it is possible to prefabricate sleepers to the appropriate lengths. At an existing turnout which is to be refurbished it is necessary to fabricate sleepers to replace existing sleepers taking into account the geometrical requirements of the existing installation.

Concrete sleepers are in widespread use in new installations and in refurbishing existing installations. As concrete sleepers are manufactured using moulds of precise dimensions under factory conditions it is not always economically feasible to cast a concrete sleeper, using customary techniques, to produce a product which can be substituted for an existing sleeper in an installed location.

SUMMARY OF INVENTION

The invention provides a method of installing a railway sleeper which include the steps of marking an elongate cast cementitious member at a plurality of locations, forming a plurality of holes through the member, each hole being at a respective location, placing at least a first element of a respective fastener in each respective hole, positioning the member below a railway line and engaging a second element of the respective fastener, with the first element, thereby to secure the railway line to the member.

The member may be marked at the plurality of locations by placing the member in a position, below the railway line, at which the member is to be secured to the railway line.

The positions of the holes, which are formed in the member, may be determined by reference to holes in at least one base plate to which the railway line is attached. By using the method of the invention the base plate is attached to the sleeper and the railway line, which is secured to the base plate, is thereby attached to the sleeper.

The holes in the member may be formed by drilling the member in situ.

Each hole may be drilled from what in use is an upper side of the member to what in use is a lower side of the member.

The first element may vary according to requirement but typically is a nut. The nut may be engaged with the member so that it does not protrude from a lower surface of the member. The nut may be fixed to the member in any appropriate way and for example may be adhesively secured to the member or grouted in position. Alternatively the nut may be mounted in a insulating holder such as a plastics sleeve or cup or the like which is frictionally or adhesively secured to the member.

In a variation of the invention the first element of a fastener is inserted into a respective hole in the cementitious member, from a lower side and a second element is inserted into the hole, from an upper side and then engaged, preferably threadedly, with the first element.

The first element may be a nut, with a head which bears on a surface of the lower side, and the second element may be an elongate bolt. An insulating sleeve or spacer may be used to prevent direct metal-to-metal contact between the fastener and a base plate to which the railway line is attached.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of examples with reference to the accompanying drawings in which:

FIG. 1 schematically illustrates a turnout in which a plurality of sleepers according to the invention can be used;

FIG. 2 is a plan view of a timber railway sleeper used in the turnout of FIG. 1 which is to be replaced using the method of the invention;

FIG. 3 is a plan view of a precast concrete sleeper;

FIG. 4 shows a fastener for use in the invention;

FIG. 5 illustrates the use of the fastener shown in FIG. 4; and

FIG. 6 shows a different type of fastener.

DESCRIPTION OF PREFERRED EMBODIMENT

FIG. 1 of the accompanying drawings illustrates in plan a turnout 10 in a railway line which is of known construction. The turnout illustrates a pair of railway tracks 12 which split into two pairs of railway tracks 14 and 16 respectively which diverge from each other. The tracks are supported on a plurality of sleepers 18. It can be seen that the sleepers are of variable lengths. Sleepers 18A, which support only the tracks 12, 14 or 16, have a conventional or standard length. Sleepers which serve both sets of tracks 14 and 16 are designated 18B and are longer than the sleepers 18A. The lengths of the sleepers vary significantly from one another.

Sleepers, historically, have been made from timber. This has given rise to problems when existing timber sleepers have to be replaced for there is a sortage of suitable timber, which is a valuable natural resource. Although concrete sleepers can be fabricated to replace the existing wooden sleepers this can normally only be done at a substantial cost. A difficulty in this connection is that the tracks 12, 14 and 16 are already in place and the concrete sleepers must then be fabricated with fastening holes or formations so that they can directly be used with the tracks without any on-site adjustment being required.

FIG. 2 illustrates a timber sleeper 18B which is engaged with lines 14A and 14B respectively of the tracks 14, and with lines 16A and 16B of the tracks 16. Each line rests on a respective base plate 22 and is secured to the base plate using conventional rail clips or fasteners which are known in the art and which, for this reason, are not further described herein. Each base plate has four holes 26 and coach bolts or similar fasteners, not shown in detail, are passed through the holes and threaded into the timber sleeper 18B to fix the base plates to the sleeper.

The method of the invention is concerned, inter alia, with the replacement of a wooden sleeper 18B of the type shown in FIG. 2 installed, as has been indicated, in a turnout or crossing as depicted in FIG. 1.

FIG. 3 illustrates an elongate cementitious member 30 of rectangular cross section which is cast under factory conditions using conventional techniques. The member has a length 32 which is chosen according to requirement and which may be one of a number of standardised lengths. The length 32 is generally equal to or slightly greater than the length of a selected sleeper 18B shown in FIG. 2, which is to be replaced.

The member 30, which has a standard cross section, is prefabricated and is reinforced using conventional prestressing techniques.

The member 30 is stored at an appropriate location and is drawn from stock, according to requirement, for use in refurbishing a rail turnout.

When a turnout is to be upgraded measurements are taken on site of the existing sleeper arrangement. A precast member 30 which, as stated, is more or less the same length as the sleeper 18B which is to be replaced, is drawn from stock. At the installation site the fasteners which secure the base plates 22 to the selected sleeper 18B are loosened. The base plates are however kept engaged with the lines 14A, 14B, 16A and 16B.

Once the sleeper 18B has been loosened from the base plates it is withdrawn from its position below the lines and the concrete sleeper 30 is pushed into position below the lines. The member 30 may be cut so that it has the same length as the wooden sleeper 18B using any appropriate technique, for example using a diamond-tip saw blade.

When the member 30 is correctly positioned below the base plates it is clamped in position and holes 34, see FIG. 5, are drilled through the member using the holes 26 in the base plates 22 as templates. Each hole is drilled through the member from what in use is its upper side 36 to its lower side 38. Fasteners of the kind shown in FIG. 4 are then used to fix the rails to the sleeper.

FIG. 4 shows a fastener 80 with a first element 82 which comprises an internally threaded metallic sleeve 84 with an open mouth 86 and an enlarged hexagonal head 88, and a second element 90 which comprises a shank 92 which is threaded over one end 94 and which has a hexagonal head 96.

An insulating sleeve 98 of a suitable plastics material is engaged with the shank 92, abuts the head 96 and, when installed, acts on an upper surface 36 of a concrete sleeper member 30, via a base plate 22 through the medium of washers 100.

The head 88 abuts the lower surface of the sleeper and thus can readily be accessed by a spanner (not shown).

The bolts are tightened so that they are firmly engaged with the nuts and the base plates are thereby secured in position. The railway lines which at all times remain secured to the base plates are thereby secured to the member 30.

It is therefore possible to fix the railway line to the member 30, via the intermediate base plate 22 directly, after the holes 34 have been drilled, in the manner shown, provided sufficient ballast underlying the member 30 has been cleared for the first element 82 to be inserted into the hole with the member 30 in situ.

The insulating sleeve 98 prevents direct metal-to-metal contact between the head 96 and the shank 92 on the one hand, and the base plate 22 on the other hand. This preserves the integrity of communication signals which are propagated through wheels and other structure of tracked vehicles on the railway lines. If this insulating action is not required then a modified fastener 80A of the type shown in FIG. 6 can be used. This fastener has an enlarged shank region 92A which effectively compensates for the removal of the insulating sleeve (i.e. increases the diameter of the shank accordingly). Another feature, which can be adopted for both fasteners, is the provision of friction enhancing formations such as splines or knurling 102 on the sleeve 84, and protrusions 106 on an inner surface of the head 88, to help the sleeve engage with the concrete sleeper so that, as the shank is tightened, there is a reduced tendency of the element 82 to rotate.

Through the use of the method of the invention the respective members 30 are accurately drilled, on site, as required so that they can directly replace wooden or other sleepers which have to be refurbished. All that is necessary in this regard is to ensure that the precast members 30 are of suitable lengths so that they can be cut to size on site to match the tracks with which they are to be used.

Claims

1. A method of installing a railway sleeper comprising the steps of: marking an elongate cast cementitious member at a plurality of locations; forming a plurality of holes through the member, each hole being at a respective location; placing at least a first element of a respective fastener in each respective hole; positioning the member below a railway line; and engaging a second element of the respective fastener, with the first element, thereby securing the railway line to the member.

2. A method according to claim 1 wherein the member is marked at the plurality of locations by placing the member in a position, below the railway line, at which the member is to be secured to the railway line.

3. A method according to claim 1 which includes the step of determining the positions of the holes, which are formed in the member, by reference to holes in at least one base plate to which the railway line is attached.

4. A method according to claim 1 wherein the holes are formed by drilling the member in situ.

5. A method according to claim 1 wherein the first element is fixed in position using a grout or an adhesive.

6. A method according to claim 1 wherein the first element is mounted in an insulating holder.

7. A method according to claim 1 wherein the first element of a fastener is inserted into a respective hole in the cementitious member, from a lower side and a second element is inserted into the hole, from an upper side, and then engaged with the first element.

8. A method according to claim 1 wherein the first element has a head which bears on a surface of the lower side, and the second element is an elongate bolt.

9. A railway sleeper which comprising: an elongate cementitious body with an upper side and a lower side; at least two base plates which are at spaced apart locations on the upper side and, for each base plate; at least two fasteners securing the base plate to the body, each fastener extending through respective registering holes in the body and in the base plate and including an internally threaded sleeve with a first head which bears against one of an upper side of the base plate and the lower side of the body; and a shank which is threadedly engaged with the sleeve and which has a second head which bears against the other of the upper side of the base plate and the lower side of the body.

10. A railway line fastener comprising: an internally threaded metallic sleeve having an open mouth and an enlarged first head, and a shank having a second head and being threaded over one end and which is threadedly engageable with the metallic sleeve.

11. A fastener according to claim 10 which includes an insulating sleeve which is engaged with the shank.

12. A fastener according to claim 10 wherein the sleeve has a plurality of friction enhancing formations on an outer surface.