GB2516706A

GB2516706A - Railway Points

Info

Publication number: GB2516706A
Application number: GB1322641.0A
Authority: GB
Inventors: Samuel David Bemment; Roger Dixon; Roger Morgan Goodall
Original assignee: Loughborough University
Current assignee: Loughborough University
Priority date: 2013-12-20
Filing date: 2013-12-20
Publication date: 2015-02-04
Anticipated expiration: 2033-12-20
Also published as: GB2516706B; GB201322641D0

Abstract

Railway points 10, based on a stub switch design, comprise pairs of parallel static stock rails 12, 14, and a pair of parallel switch rails 16 movable between first and second positions aligning respectively with stock rail pairs 12, 14. At least one switch rail 16 cooperates with a stock rail 12, 14 when switch rails 16 are in the first and second positions, with a mating profile 50 aligning a switch rail 16 and a stock rail 12, 14 and preventing a switch rail 16 from moving transversely relative to a stock rail 12, 14. Mating profile (50, Figure 4) may be a U-section or V-section; suitably a convex profile (26, Figure 4) extends upwardly from stock rails 12, 14 and a concave profile (32, Figure 4) is formed in switch rails 16, allowing switch rails 16 to move vertically to engage stock rails 12, 14. Switch rails 16 and stock rails 12, 14 may taper, forming a mitred connection allowing movement between them.

Description

RAILWAY POINTS

Technical Field

The present disclosure relates generally to railway points and more particularly to a railway points arangement for a railway track junction.

Technical Background

Railway points, also known as railway track switches, are a necessary part of all railway networks as they enable different routes through the network to be selected. They are a critical part of the network as a points failure often leads to delays, re-routing and cancellations. Even when fully operational, railway points represent a significant capacity constraint because they have to be operated in such a way to ensure that a route has been correctly set before rolling stock is allowed to pass the railway track junction, lii a traditional set of railway points, movable switch rails are located between stock rails. The stock rails are securely fixed to prevent movement and the free ends of the switch rails, which are linked together via stretcher bars, slide on suitable supports when commanded to move enabling either a straight route or a turnout route to be selected.

Upon request from the signalling system, an actuator, which forms part of the lineside points operating equipment, moves the two switch rails via a linkage before locking the switch rails in position and communicating the detected position of the rails and the lock back to the signalling system. It is only once this process is complete that a train can be authorised to safely pass the track junction because during the transition' state, when the switch rails are not properly set to select either the straight route or the turnout route, the points present a derailment risk.

In an alternative type of railway points, commonly known as a stub switch, the ends of a pair of movable switch rails are moved between different positions into alignment with pairs of static stock rails to form a continuation of the main fixed rails on either side of the railway track junction. Stub switches have never achieved widespread usage for a number of reasons. One reason is difficulty aligning the free rail ends. If not correctly aligned, the loads on the free rail ends imparted by rolling stock can lead to premature wear of the rail ends and hence failure of the stub switch. Severe misalignment can, of course, also present a derailment risk. Another reason is that, as the rails expand during hot weather, the clearance between the free rail ends decreases and in extreme cases they can becomejammed preventing movement of the switch rails and hence failure of the stub switch. Nevertheless, stub switches arguably offer significant advantages over the traditional railway points discussed above, including a reduced likelihood of blockages, the possibility of multiple routes from a single set of points, and cheaper modular constmction using standard components.

The present disclosure seeks to provide a railway points arrangement, based on the stub switch design, which overcomes the drawbacks outlined above that are associated with railway points based on the traditional and stub switch designs.

Summary of the Disclosure

According to a first aspect of the present disclosure, there is provided a railway points arrangement for a railway track junction, the railway points arrangement comprising: at least first and second pairs of longitudinally-extending, parallel-spaced static stock rails defining respectively a first route and a second route; a pair of longitudinally-extending, parallel-spaced switch rails movable between a first position in alignment with the first pair of stock rails to select the first route and a second position in alignment with the second pair of stock rails to select the second route; wherein at least one of the movable switch rails cooperates with at least one stock rail of each of the first and second pairs of stock rails when the movable switch rails are in the first and second positions, said at least one switch rail and said at least one stock rail being shaped lo define a mating profile which aligns the switch rail and stock rail and prevents transverse movement of the switch rail relative to the stock rail.

The mating profile between the switch rail and stock rail ensures that the switch rail and stock rail are correctly aligned when the switch rails are in the first and second positions and further ensures that the switch rails cannot move from either the first or second position in a transverse horizontal direction unless specifically commanded to do so. The railway points do not, therefore, rely exclusively on lineside points operating apparatus to accurately align the switch rails with the stock rails and to lock the switch rails in the selected position.

It is possible, in one embodiment, that only one of the movable switch rails cooperates with a corresponding stock rail of each of the first and second pairs of stock rails when the movable stch rails are in the first and second positions. In this embodiment, only one of the switch rails and one of the stock rails of each of the first and second pairs of stock rails are shaped to define a mating profile. The other switch rail and stock rail of each pair can have a conventional stub switch design in which the facing ends of the rails are longitudinally separated. Such an arrangement typically requires that the switch rails are secured together, for example by a stretcher bar, to ensure proper alignment between both switch rails and both stock rails of each of the first and second pairs and to ensure that both switch rails are constrained against transverse horizontal movement relative to the stock rails.

In preferred embodiments, both of the movable switch rails cooperate with both stock rails of each of the first and second pairs of stock rails when the movable switch rails are in the first and second positions, and both switch rails and both stocks rails in each of the first and second pairs are shaped to define a mating profile which aligns the switch rails and stock rails and prevents transverse movement of the switch rails relative to the stock rails, This arrangement may be preferred because each switch rail is independently aligned with a corresponding stock rail and independently transversely constrained.

The mating proflle may be arranged lo peiniii the switch rail to be moved vertically relative to the stock rail to engage and disengage the mating profile. The vertical motion may be about an arcuate path. The switch rails can, thus, be moved transversely and vertically, possibly simultaneously transversely and vertically, about said arcuate path between the first and second positions so that either the first or second route can be selected. Because the switch rail must be raised, for example by an actuator arrangement, to disengage the mating profile to permit movement of the switch rails between the first and second positions, there is no risk of unintended movement of the switch rails between the first and second positions in a transverse horizontal direction.

The mating profile may be arranged to permit relative longitudinal movement between the switch rail and the stock rail with which it cooperates when the switch rails are in the first and second positions. By arranging the mating profile to permit relative longitudinal movement, thermal expansion and contraction can take place at the interface between the switch rail and the stock rail without the switch rails and stock rails becomingjammed together. The running surfaces of the switch rail and stock rail remain coplanar in the event of any relative longitudinal movement.

The mating profile may comprise a convex profile section and a complementary shaped concave profile section. The convex profile section may extend upwardly from the stock rail and the concave profile section may be formed in the switch rail, for example in a lower surface thereof This arrangement is advantageous because the concave profile section is inverted and cannot become blocked with debris which could prevent the convex profile section from properly locating in the concave profile section.

Nevertheless, it is possible that the convex profile section could extend downwardly from the switch rail, for example from a lower surface thereof and that the concave profile section could be formed in the stock rail, for example in an upper surface thereof The mating profile could comprise a plurality of cooperating mating surfaces, For example, the stock rail could include a plurality of mating surfaces which cooperate with corresponding mating surfaces on the switch rail.

Generally, a relatively simple geometry is preferred to facilitate manufacture of the rails. Accordingly, the mating profile may comprise a generally V-section profile. Thus, the switch rail and the stock rail may each include two cooperating mating surfaces.

The V-section profile may be inverted which provides an arrangement in which the convex profile section advantageously extends upwardly from the stock rail and the concave profile section is advantageously formed in the switch rail.

In an alternative embodiment, the mating profile may be a generally U-section profile and the U-section proffle may be inverted.

lii typical embodiments, a recess or expansion gap may be defined between facing end surfaces of the switch rail and the stock rail with which it cooperates when the switch rails are in the first and second positions. The recess or gap ensures that any longitudinal movement due to thermal expansion can be readily accommodated without the switch rails and stock rails becomingjammed together.

The switch rail and the stock rail may be tapered in the longitudinal direction to define a mitred connection between the switch rail and the stock rail. The mitred connection advantageously permits relative longitudinal movement between the switch rail and the stock rail. Again, this ensures that any longitudinal movement due to thermal expansion can be readily accommodated without any resultant discontinuity in the mnning surface at the interface between the switch rail and the stock rail.

Brief Description of the Drawings

Figure t is a diagrammatic perspective view of a railway points arrangement according to the present disclosure comprising switch rails and stock rails; Figure 2 is an enlarged diagrammatic perspective view of one of the stock rails shown in Figure 1; Figure 3 is an enlarged diagrammatic perspective view of one of the switch rails shown in Figure 1; and Figure 4 is a diagrammatic cross-sectional view of the regional labelled A' in Figure 1 showing one possible form of mating profile between the switch rail and the stock rail,

Detailed Description of Embodiments

Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings.

Figure 1 iHustrates a railway points arrangement 10 for a railway track junction which enables different routes to be selected through the junction. The points arrangement 10 comprises first and second pairs of longitudinally-extending, parallel-spaced static stock rails 12, 14 mounted on fixed supports 15 in the form of sleepers or bearers. The stock rails 12, 14 have running surfaces I 2c, I 4c. The first pair of stock rails 12 defines a first route, for example a straight route. The second pair of stock rails 14 defines a second route, for example a turnout route.

The points arrangement 10 also includes a pair of longitudinally-extending, parallel-spaced switch rails 16 having running surfaces ióc. In Figure 1, the switch rails 16 are shown in a first position in which they are aligned with the first pair of stock rails 12 and have coplanar running surfaces 16c, 12c thus enabling rolling stock to follow the first route through the railway track junction. As will be explained in further detail below, the switch rails 16 can be moved between the illustrated first position and a second position in which they are aligned with the second pair of stock rails 14 and have coplanar running surfaces 1 6c, 14c thus enabling rolling stock to follow the second route through the railway trackjunction.

Although not illustrated in Figure,it will be appreciated that the stock rails 12, 14 and the switch rails 16 are secured to plain line rails which define the respective route either side of the railway track junction, for example the straight route and the turnout route.

The stock rails U, 14 and switch rails 6 could, for example, be secured to the plain line rails by suitable fastenings which are passed through openings 18 provided in a web section of each rail 12, 14, 16 and which engage in corresponding openings in a fish plate arrangement that is also secured to the plain line rails. Alternatively, the stock rails 12, 14 and switch rails 16 could be secured lo the plain line rails by welding, in which case openings 18 do not need to be provided in the web section.

Referring now to Figures 1 to 4, the switch rails 16 cooperate with the stock rails 12, N when the switch rails 16 are in the first position (shown in Figure 1) and the second position (not shown). In particular, the switch rails 16 and stock rails 12, 14 are shaped to define a mating profile 50 (see Figure 4) which aligns the switch rails 16 with the stock rails U, 14 and prevents the switch rails 16 from moving transversely, in the horizontal direction, relative to the stock rails 12, 14. The particular arrangement and geometry of the mating profile 50, a preferred embodiment of which will be explained in further detail below with respect to one of the switch rails 16 and stock rails 12, acts as a self-alignment feature which ensures that the switch rails 16 and the stock rails 2, 14 are always accurately aligned when the switch rails 16 are in either the first position or the second position.

The stock rail 12, 14 includes a base portion 20 having upwardly sloped converging surfaces 22, 24 which define an upwardly extending convex profile section 26 extending longitudinally along at least part of the stock rail 12. Similarly, the switch rail 16 includes a concave profile section 32 defined by upwardly sloped converging surfaces 28, 30. The convex profile section 26 is accommodated in the concave profile section 32 when the switch rails 16 are in the first and second positions and the switch rail t6 is thus constrained against movement in the transverse horizontal direction, In the illustrated embodiment, the convex profile section 26 and the concave profile section 32 form an inverted generally V-section profile 50. Other configurations, such as an inverted generally U-section profile, are however possible.

In order to move the switch rails 16 between the first and second positions, an actuator arrangement (not shown) is used to raise the switch rails 16 by at least a distance which is sufficient to disengage the convex profile section 26 from the concave profile section 32. The actuator arrangement transversely and vertically moves the switch rails 16 to a position in which they are transversely and vertically aligned with either the first pair of stock rails 12 or the second pair of stock rails 14 depending on the desired route, the switch rails 16 being lowered to engage the convex profile section 26 in the concave profile section 32. Any suitable actuator arrangement can be used to raise/lower and move the switch rails 16 transversely between the first and second positions. A particularly suitable actuator arrangement is described in a related co-pending patent application filed by the applicant on the same date as the present application and entitled "Railway Points Operating Apparatus".

In accordance with aspects of the present disclosure, when the switch rails 16 are moved between the first and second positions, the actuator arrangement does not need to move the switch rails 16 to a position in which they are perfectly transversely aligned with the stock rails t2, 14. This is because the cooperation between the sloped mating surfaces 22, 28 and 24, 30 guides the switch rails 16 transversely and downwardly, for example about an arcuate path, into a position in which the running surfaces t6c, 12c, and 16c, Nc are coplanar and the switch rails 16 and stock rails 12, 14 are transversely aligned. The mating surfaces 22, 28 and 24, 30 thus ensure that the switch rails 16 are always in proper alignment with the stock rails 12, 14 when the switch rails 16 are in the first or second position.

In order to allow a gradual transfer of rolling forces between the mnning surface l6c (in particular the running edges I 6b) of the switch rails 16 and the running surfaces 2c, 14c (in particular the running edges 12b, 14b) of the stock rails 12, 14, the switch rails 16 and stock rails 12, 14 are shaped to provide a mitred connection 38. As can be clearly seen in Figure 1, the mitred connection 38 provides a continuous and smooth running edge surface for rolling stock passing the railway track junction.

In the illustrated embodiment, the mitred connection 38 is defined by cooperating pairs of substantially vertical faces 40a, 40b, 42a, 42b and 44a, 44b which may also help to transversely align the switch rails 16 and the stock rails 12, 14. Any suitable geometry can, however, be adopted to form the mitred connection.

The stock rails 12, 14 and the switch rails 6 have pairs of facing end surfaces 48a, 48b and SOa, Sob. The respective pairs of facing end surfaces 48a, 48b and SOa, SOb are spaced from each oiher when the switch rails 16 are in the first and second positions to define expansion gaps 52 which are best seen in Figure 1. These gaps 52 ensure that if there is longitudinal thermal expansion of the stock rails 12, 14 and/or the switch rails 16, the ends of the switch rails 16 do not become jammed or fouled against the ends of the stock rails 12, N. Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to those embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments.

Each feature disclosed in the specification, including the claims and drawings, may be replaced by alternative features serving the same, equivalent or similar purposes, unless expressly stated otherwise.

For example, although the illustrated embodiment has only first and second pairs of stock rails 12, 14 which enable the points arrangement 10 to select between first and second routes through the railway track junction, further pairs of stock rails could be provided with which the switch rails 16 can cooperate thereby enabling more than two routes to be selected.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

Any combination of the above-described features in all possible variations thereof is encompassed by the present invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

Claims 1. A railway points arrangement for a railway track junction, the railway points arrangement comprising: at least first and second pairs of longitudinally-extending, parallel-spaced static stock rails defining respectively a first route and a second route; a pair of longitudinally-extending, parallel-spaced switch rails movable between a first position in alignment with the first pair of stock rails to select the first route and a second position in alignment with the second pair of stock rails to select the second route; wherein at least one of the movable switch rails cooperates with at least one stock rail of each of the first and second pairs of stock rails when the movable switch rails are in the first and second positions, said at least one switch rail and said at least one stock rail being shaped to define a mating profile which aligns the switch rail and stock rail and prevents transverse movement of the switch rail relative to the stock rail.
2. A points arrangement according to claim 1, wherein the mating profile is arranged to permit said at least one switch rail to be moved in a vertical direction relative to said at least one stock rail to engage and disengage the mating profile and thereby permit transverse movement of the switch rails between the first and second positions.
3, A points arrangement according to claim I or claim 2, wherein the mating profile is arranged to permit relative longitudinal movement between said at least one switch rail and said at least one stock rail when the switch rails are in the first and second positions.
4. A points arrangement according to any preceding claim, wherein the mating profile comprises a convex profile section and a complementary concave profile section.
5, A points arrangement according to claim 4, wherein the convex profile section extends upwardly from said at least one stock rail and the concave profile section is formed in said at east one switch rail.
6. A points an-angement according to any preceding claim, wherein the mating profile comprises a plurality of cooperating mating surfaces.
7. A points arrangement according to any preceding claim, wherein the mating profile is a generally V-section profile.

8, A points arrangement according to claim 7, wherein the V-section profile is inverted, 9. A points arrangement according to any of claims 1 to 5, wherein the mating profile is a U-section profile.10. A points arrangement according to claim 9, wherein the U-section profile is inverted, 11. A points arrangement according to any preceding claim, wherein an expansion gap is defined between the facing end surfaces of said at least one switch rail and said at least one stock rail when the switch rails are in the first and second positions.U, A points arrangement according to any preceding claim, wherein said at least one switch rail and said at least one stock rail are tapered in the longitudinal direction to define a mi tred connection that permi Is i'd alive longitudinal movement between said at least one switch rail and said at least one stock rail.13, A points arrangement according to any preceding claim, wherein both of the movable switch rails cooperate with both stock rails of each ofthe first and second pairs of stock rails when the movable switch rails are in the first and second positions, and both switch rails and both stocks rails of each of the first and second pairs are shaped to define a mating profile which independently aligns each switch rail with a corresponding stock rail and prevents transverse movement of the switch rails relative to the stock rails.N, A railway points arrangement for a railway track junction substantially as hereinbefore described 2md/or as shown in the accompanying drawings.