GB2516712A

GB2516712A - Railway track crossing

Info

Publication number: GB2516712A
Application number: GB1403674.3A
Authority: GB
Inventors: Samuel David Bemment
Original assignee: Loughborough University
Current assignee: Loughborough University
Priority date: 2014-03-03
Filing date: 2014-03-03
Publication date: 2015-02-04
Anticipated expiration: 2034-03-03
Also published as: GB2516712B; GB201403674D0

Abstract

A railway track crossing (40, fig 2) comprises a fixed crossing nose 42 formed by a pair of diverging rails (44) and a pair of independently movable rails 45 each having a wing rail 46 provided on each side of the crossing nose. Each rail is movable transversely from a closed position, in which the wing rail contacts the crossing nose, to an open position, in which the wing rail is spaced from the crossing nose to form a groove 54 that allows the passage of a wheel flange 56a between the crossing nose and the wing rail. An actuator arrangement (60, fig. 11) is operable to move one of the movable rails from the closed position to the open position and each movable rail is arranged to adopt the closed position in the absence of any force applied to it by the actuator arrangement. Each movable rail includes a mating feature 78 which cooperates with a mating feature 82 to lock the movable rail in the closed position when the movable rail is loaded by the wheels 56 of rolling stock passing through the railway track crossing.

Description

RAILWAY TRACK CROSSING

Technical Field

The present disclosure relates generally to a railway track crossing at which the rails of two diverging railway tracks cross, for example defining a straight route and a turnout route. The diverging tracks are selectable in a conventional manner using a railway points arrangement so that rolling stock can travel along either the straight route or the turnout route.

Technical Background

A conventional railway track] unction 10 which allows rolling stock to follow different routes through the rail network is illustrated in Figure 1. The railway track junction 10 includes a points arrangement 16, also known as a railway track switch, which enables different routes, for example a straight route 12 and a turnout route 14, to be selected through the railway track junction 10 by allowing rolling stock to transfer between different railway tracks. The points arrangement 16 illustrated in Figure 1 comprises a traditional set of railway points in which movable switch rails 18 are located between stock rails 20. The stock rails 20 are securely fixed to prevent movement and the free ends of the stch rails 18, which are linked via stretcher bars (not shown in Figure 1), slide transversely on suitable supports when commanded to move enabling either the straight route 12 or the turnout route 14 to be selected. In an alternative type of railway points, commonly known as a stub switch, the ends of a pair of movable switch rails are moved transversely between different positions into alignment with pairs of fixed stock rails to form a continuation of the main fixed rails on either side of the railway track junction.

The railway track junction 10 includes a railway track crossing 22 where the rails of one track (e.g. the straight track) cross the rails of the other track (e.g. the turnout track).

Also known as a "common crossing" or "frog", the railway track crossing 22 includes a v-section nose 24 which is formed by a pair of fixed diverging rails 26 (one of each track). A pair of wing rails 28 is located on either side of the nose 24 to strengthen the structure (transmit longitudinal stress) and to provide a smooth transfer of load.

In a "fixed" crossing such as that shown in Figure 1, which is the most common type of railway track crossing, the v-section nose 24 and wing rails 28 are fixed in position arid the wing rails 28 are spaced apart from the v-section nose 24 by a small distance to form a groove 30 between each wing rail 28 and the nose 24 through which the wheel flanges of the rolling stock wheels can pass. Check rails 34 are provided to ensure that the wheels follow the correct route through the railway track crossing 22 and to ensure that the rolling stock does not derail. Before a wheel flange can engage in one of the grooves 30, the wheel must first traverse a gap 32 formed by the other groove 30 between the nose 24 arid the other wing rail 28. The wheel is temporarily unsupported as it traverses this gap 32 and the impact between the wheel arid the nose/wing rails results in both noise and an increased rate of wear of the nose 24 and the wing rafls 28.

In an attempt to address these proNems, "swing nose" and "swing wing" crossings have been proposed.

In a swing nose crossing, the v-section nose 24 can move transversely so that it contacts one of the wing rails 28 and closes the gap 32 between the nose 24 and the wing rail 28 to provide a continuous length of rail for the wheels of the rolling stock. It will be appreciated that the position of the nose 24 (and hence which of the wing rails 28 it contacts) will vary according to the setting of the points arrangement 16 and, hence, whether the straight track or the turnout track needs to be selected. Swing nose crossings can either be "passive", meaning that the v-section nose 24 is moved transversely by the wheels of rolling stock, or "active", meaning that the v-section nose 24 is moved by an actuator arangement. It should be noted that in a "passive" swing nose crossing, the v-section nose 24 is only moved transversely by the wheels of rolling stock when the rolling stock passes through the crossing iii (lie trailing-point direction, i.e. the converging direction of the rails forming the v-section nose 24.

lii a swing wing crossing, the v-section nose 24 is fixed and one or both of the wing rails 28 is movable. One example of a "passive" swing wing crossing is described in GB 1587042. In this passive arrangement, one of the wing rails is fixed whilst the other wing rail is flexible and call be moved transversely, from a closed position to an open position, by a passing wheel of rolling stock. In the closed position (set for the straight route), the flexible wing rail contacts the nose to provide a continuous mnning surface along the straight route for the rolling stock wheels. In the open position (set for the turnout route), the movable wing rail is pushed away from the nose by a passing wheel flange so that the rolling stock can travel along the turnout route. When following the turnout route, the wheels still have to traverse a gap between the fixed wing rail aiid the nose but this is not problematic if the turnout speed is quite low, In practice, there is an increasing demand for higher turnout speeds in order to increase network capacity. As a result, "active" swing wing crossings have been proposed in which an actuator arrangement is provided to move the wing rails transversely into and out of contact with the nose so that there are no gaps (i.e. a continuous running surface) when rolling stock travels along either the straight route or the turnout route, Despite the obvious advantages of swing nose and swing wing crossings, including reduced wear of the v-section nose and wing rails, reduced noise and higher possible turnout speeds, they have seen limited use in the UK. This is because the aforementioned advantages are outweighed by disadvantages such as high cost, complexity and poor reliability. In fact, swing nose crossings are no longer fifted on the UK mainline rail network due to performance and reliability issues, There is, therefore, a need for a railway track crossing which overcomes these disadvantages.

Summary of the Disclosure

According to a first aspect of the present disclosure, there is provided a railway track crossing comprising: a fixed crossing nose formed by a pair of diverging rails; a pair of independenily movable rails each having a wing rail section provided on each side of the fixed crossing nose, each rail being movable transversely from a closed position in which the wing rail section contacts the crossing nose to an open position in which the wing rail section is spaced from the crossing nose to form a groove that allows the passage of a wheel flange between the crossing nose and the wing rail section; and an actuator arrangement which is operable to move a selected one of the movable rails from the closed position to the open position, each movable rail being arranged to adopt the closed position in the absence of any force applied to it by the actuator arrangement; wherein each movable rail includes a first mating feature which cooperates with a second mating feature to lock the movable rail in the closed position when the movable rail is loaded by the wheels of rolling stock passing through the railway track crossing.

The actuator arrangement moves a selected one of the movable rails from the closed position to the open position when rolling stock needs to travel along either the straight route or the turnout route. The other movable rail remains in the closed position, with its wing rail section in contact with the fixed crossing nose to provide a continuous running surface for the rolling stock wheels, and is positively locked in the closed position by the weight of passing rolling stock acting on the movable rail. The locking of each movable rail in the closed position is, therefore, achieved entirely passively by virtue of cooperation between the first and second mating features and does not rely on the actuator arrangement or other active locking mechanisms, The railway track crossing is consequently safer and more reliable than existing railway track crossings and can accommodate high turnout speeds because the wheels of passing rolling stock are fully supported throughout the crossing, in contrast to existing fixed crossings as discussed above.

Because the movable rails are arranged to adopt the closed position in the absence of any force applied by the actuator arrangement, the movable rails remain in the closed position at all limes when the railway nack crossing is not iii use (i,e. when rolling stock is not passing through the railway track crossing), Accordingly, there is minimal risk of the movable rails becoming stuck in the open position, for example as a result of a blockage formed by debris becoming lodged in the groove between an open wing rail section and the crossing nose, An additional advantage is that rolling stock can safely pass through the railway track crossing in any direction and along any route, irrespective of the route for which the movable rails are actuafly set. The railway track crossing does not, therefore, present a derailment risk.

Each movable rail may adopt a first position in which its wing rail section is elevated above the crossing nose when the movable rail is not loaded by the wheels of rolling stock and each movable rail may be arranged to move downwardly, to a second position, when loaded by the wheels of rolling stock passing through the railway track junction. The first arid second mating features may be arranged to cooperate when the movable rail is loaded by the wheels of rolling stock and thereby moved to the second position. Accordingly, the simple loading of the movable rail by the passing rolling stock and the consequent downward movement of the movable rail causes the loaded movable rail to be locked in the closed position as a result of the cooperation between the first and second mating features.

A running surface of each wing rail section may be elevated above a running surface of the crossing nose when each movable rail is not loaded by the wheels of rolling stock and in the first position. The running surface of each wing rail section may be substantially level or substantially coplanar with the running surface of the crossing nose when the movable rail is loaded by the wheels of rolling stock and in the second position. This ensures that a continuous running surface is provided for the wheels of rolling stock passing through the railway track crossing.

The railway track crossing may include a plurality of biasing means. The biasing means may be arranged to bias each movable rail into the elevated first position when each movable rail is not loaded by the wheels of rolling stock, The biasing means thus support the movable rails in the longitudinal direction (i.e. along the running direction of the rails) and ensure that the movable rails adopt the elevated first position when they are not loaded by the wheels of passing rolling stock. The biasing means may be arranged to bias each movable rail into the closed position. The biasing means thus ensure that each movable rail adopts the closed position when each movable rail is not loaded by the wheels of rolling stock and when no force is applied by the actuator arrangement. The biasing means thus help to place the movable rails, and hence the railway track crossing, in a neutral, safe, state.

The railway track crossing may include a plurality of dampers. At least one of said dampers may be arranged to retard the movement of each movable rail from the second position to the first position and possibly from the open position to the closed position.

The dampers ensure that each movable rail does not repeatedly spring upwardly from the second position to the elevated first position (under the action of the biasing means) as each wheelset passes through (there could be a few seconds between each wheelset passing). Additionally, should a wheelset pass through with the movable rails, and hence the wing rail sections, set incorrectly for the desired route, the dampers would prevent the unloaded movable rail trying to slam to the closed position immediately after each wheel flange passes through the groove between the wing rail section and the crossing nose, Although this is a somewhat unlikely occurrence, it could potentially prevent a lot of noise, vibration and wear as a large number of wheelsets (e.g. upwards of forty wheelsets) pass through per train.

The first and second mating features may comprise a concave profile section extending longitudinally along the mnning direction of the movable rails and a complementary convex profile section extending longitudinally along the running direction of the movable rails, The convex profile section may extend downwardly from a lower flange of each movable rail, The concave profile section may open upwardly to accommodate the convex profile section when the movable rail is in the second position.

The railway track crossing may include a locking element positioned beneath the movable rail in which the upwardly opening concave profile section may be fonned, In one embodiment, a separate locking element may be positioned beneath each movable rail, In another embodiment, a single locking element may extend transversely between the movable rails and may include transversely spaced concave profile sections positioned beneath each movable rail.

The convex profile section and the concave profile section may each include a bearing surface which may be configured to guide each movable rail downwardly to the second position when the movable rail is loaded by the wheels of rolling stock passing through the railway track crossing The bearing surfaces may be configured to guide each movable rail upwardly from the first position to a third position, elevated above the first position, when the movable nil is moved from the closed position to the open position by the actuator arrangement.

The actuator arrangement may include an actuating member which may be movable transversely to move a selected one of the movable rails from the closed position to the open position. The actuating member may be positioned between the movable rails. In some embodiments, each movable rail includes a converging rail section which converges between a fixed end and a constriction and the wing rail section diverges from the constriction on each side of the fixed crossing nose towards a free end. The actuating member may be positioned between the converging rail sections. The actuating member may be set to a neutral position out of contact with the movable rails, and in particular the converging rail sections, when the movable rails are in the closed position.

The actuating member may include a longitudinally extending contoured upper surface which may have ramp sections at longitudinally opposite ends thereof. The ramp sections advantageously help to guide and may possibly help to re-rail the wheels of rolling stock passing through the railway track junction in the extremely unlikely event that the movable rails, and hence the wing rail sections, are incorrectly set for the desired route.

The actuator arrangement may include a controllable drive mechanism which is selectively operable to transversely move the actuating member. The actuating member does not cooperate with the movable rails when they are in the closed position and can be moved into contact with only one of the movable rails at a time depending on the mute that needs to be selected through the railway track crossing. The controllable drive mechanism may be backdrivable and may include a plurality of independent actuator drives, for example three actuator drives. The use of a plurality of independent actuator drives provides the required degree of redundancy.

Each wing rail section typically includes a flared section at its free end which is spaced from the crossing nose when the movable rail is in the closed position. This ensures that each wing rail section, and hence each movable rail, can be moved transversely by the wheel flanges of rolling stock executing a trailing-point movement in the converging direction of the rails forming the fixed crossing nose. As a result, the railway track crossing does not present a derailment risk to rolling stock executing such a movement even if the position of the movable rails, and hence the wing rail sections, is incorrectly set for the desired route, for example due to failure of the actuator arrangement,

Brief Description of the Drawings

Figure 1 is a plan view of a railway track junction including a set of railway points and a conventional "fixed" railway track crossing; Figure 2 is a plan view of a railway track crossing according to the present disclosure in which each of the movable rails is in a closed position; Figure 3 is a view similar to Figure 2 in which the railway track crossing is set for the straight route shown in Figure 1 with one of the movable rails in an open position; Figure 4 is a view similar to Figures 2 and 3 in which the railway track crossing is set for the turnout route shown in Figure 1 with the other of the movable rails in an open position; Figures 5 and 6 are cross-sectional views respectively along the lines A-A and B-B of Figure 2; Figures 7 and 8 are cross-sectional views respectively along the lines C-C and D-D of Figure 3 showing the movable rail iii the closed position in an unloaded stale; Figures 9 and 10 are cross-sectional views similar to Figures 7 and 8 showing the movable rail loaded by a wheel of passing rolling stock; Figure It is an enlarged plan view of part of an actuator arrangement; and Figure 12 is a perspective view of an actuating member.

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.

Figures 2 to 12 illustrate a railway track crossing 40 according to the present disclosure.

The railway track crossing 40 forms part of a railway track junction 10 such as that shown in Figure in place of the fixed railway track crossing 22.

Referring initially to Figures 2 to 4, the railway track crossing 40 includes a v-section fixed crossing nose 42, formed by a pair of diverging rails 44, and a pair of movable rails 45 each having a wing rail section 46 provided on each side of the fixed crossing nose 42. The diverging rails 44 and movable rails 45 are mounted in a conventional manner on fixed supports 43 in the fonn of sleepers or bearers. The movable rails 45 include converging rail sections 49 which converge from a fixed end 48 towards a constriction 50, The wing rail sections 46, which form a continuation of the converging rail sections 49, diverge from the constriction 50 on each side of the fixed crossing nose 42 towards a free end 52. Each of the movable rails 45 is independently movable between a closed position, shown in Figures 2, 5 and 6, in which its wing rail section 46 contacts the crossing nose 42, and an open position, shown in Figures 3, 4, 7, 8, 9 and 10, in which its wing rail section 46 is spaced from the crossing nose 42. When each movable rail 45 is in the open position, a groove 54 (Figures 3, 4 and 10) is provided between the crossing nose 42 and the wing rail section 46 to allow the passage of a wheel flange 56a. As can be clearly seen in Figure 2, each wing rail section 46 includes a flared section 58 at its free end 52 which is spaced from the crossing nose 42 when the movable rail 45 is in the closed position.

An actuator arrangement 60 (see Figure 1) is provided to move a selected one the movable rails 45 from the closed position to the open position by applying a transverse force to the selected movable rail 45. In the absence of any transverse force being applied to the movable rails 45 by the actuator arrangement 60, the movable rails 45 adopt the closed position shown in Figures 2 and 6 thereby placing the railway track crossing 40 in a neutral state. The actuator arrangement 60 includes an actuating member 62 located between the converging rail sections 49, at a position between the fixed ends 48 and the constriction 50.

The actuator arrangement 60 includes an actuator arm 64 which cooperates at one end with the actuating member 62 by virtue of engagement of an upwardly projecting leg 66 in a recess 68 formed in the actuating member 62. The other end of the actuator arm 64 cooperates with a trackside controllable drive mechanism (not shown), such as an actuator bank including a plurality of backdrivable independent actuator drives. The controllable drive mechanism can be operated in a conventional manner to displace the actuator arm 64, and hence the actuating member 62, transversely. The actuating member 62 can consequently be moved transversely into contact with a selected one of the movable rails 45, and in particular the converging rail sections 49, and can thereby displace the selected movable rail 45 transversely from the closed position to the open position.

When the movable rails 45 are in the closed position, they can move vertically between a first position, shown in Figures 5 and 6, and a second position, shown in Figures 9 md 10 (see the left movable rail 45), When the movable rails 45 are in the first position, the running surface 70 of the wing rail sections 46 is raised slightly above to the running surface 72 of the crossing nose 42. When the movable rails 45 are in the second position, the running surface 70 of the wing rail sections 46 is substantially coplanar with the running surface 72 of the crossing nose 42 thereby providing a continuous running surface for the wheels 56 of passing rolling stock.

The railway track crossing 40 includes a plurality of biasing means 74 in the form of compression springs which are spaced longitudinally along the running direction of each movable rail 45. The primary purpose of the biasing means 74 is to bias the movable rails 45 into the elevated first position shown in Figures 5 and 6 and to thereby prevent the movable rails 45 from moving to the second position under their own weight (i.e. from sagging). Due to the inclination of the biasing means 74 in the illustrated embodiment, it will be appreciated that the biasing means 74 also help to bias the movable rails 45 into the closed position, such that the wing rail sections 46 are in contact with the crossing nose 42. Referring to Figures 9 and 10, it will be seen that when a selected one of the movable rails 45 is in the closed position and is loaded by the wheels 56 of rolling stock passing through the railway track crossing 40 (the left movable rail in Figures 9 and 10), the load applied to the movable rail 45 displaces it from the elevated first position to the second position thereby compressing the biasing means 74. After rolling stock has passed through the railway track crossing 40, the movable rail 45 is biased upwardly to the elevated first position by the biasing means 74.

The railway track crossing includes a plurality of dampers 76 which, like the biasing means 74, are spaced longitudinally along the running direction of each movable rail 45, The dampers 76 retard the movement of the movable rails 45 in the upward direction, from the second position to the first position, and may also retard movement of the movable rails 45 from the open position to the closed position if the movable rails 45, and hence the wing rail sections 46, are incorrectly positioned for the desired route, as will be explained in further detail below.

Each movable rail 45 includes a first mating feature 78 in the form of a convex profile section 80 which extends longitudinally along the running direction of each movable rail 45. The convex profile section 80 projects downwardly from a lower flange 47 of each movable rail 46. The railway track crossing 10 also includes a second mating feature 82 in the form of an upwardly opening concave profile section 84 which extends longitudinally along the running direction of each movable rail 45, In the illustrated embodiment, a longitudinally extending locking element 86 is positioned beneath the movable rails 45 and the concave profile sections 84 are formed at transversely spaced positions in ihe locking elemeni 86, As can be clearly seen iii Figures 9 and 10, when the movable rail 45 which is in the closed position is loaded by the wheels 56 of rolling stock passing through the railway track crossing 40 so that it is moved to the second position, the convex profile section 80 engages the concave profile section 84, This engagement prevents any transverse movement of the movable rail 45, and hence the wing rail section 46, and ensures that the movable rail 45 is locked in the closed position, with the wing rail section 46 in contact with the crossing nose 42, whilst it is loaded by the wheels 56 of passing rolling stock.

Each convex profile section 80 includes a bearing surface 88 having a substantially semi-circular curved surface portion 88a provided by a shoulder 90 and a substantially linear surface portion 88b which is inclined upwardly away from the crossing nose 42 in the transverse direction. Each concave profile section 84 also includes a bearing surface 92 having a correspondingly shaped curved surface portion 92a and an upwardly inclined linear surface portion 92b. As will be clear from Figures 9 and 10, the various surface portions 88a, 88b, 92a, 92b of each bearing surface 88, 92 are in intimate contact when the movable rail 45 is in the second position. It is this intimate contact that locks the movable rail 45 in the closed position. When one of the movable rails 45 is moved from the closed position to the open position (i.e. the position adopted by the right hand movable rail 45 in Figures 7 to 10), the bearing surfaces 88, 92 cooperate to guide the movable rail 45 upwardly, from the first position to a third position which is elevated above the first position. More particularly, the curved surface portion 88a provided by the shoulder 90 contacts the curved surface portion 92a and the linear surface portion 92b thereby guiding the movable rail 45 upwardly.

The operation of the railway track crossing 40 will now be described with reference to the accompanying drawings.

When it is not intended that rolling stock should pass through the railway track crossing and, therefore, when the railway track crossing 40 is not in use, the controllable drive mechanism is set so that the actuating member 62 adopts a neutral transverse position in which it does not apply any Force to eiiher oF ihe movable rails 45, As a resuli both of the movable rails 45 adopt the closed position illustrated in Figures 2, 5 and 6.

Furthermore, in the absence of any load applied to the movable rails 45 by rolling stock, the movable rails 45 are biased into the elevated first position by the biasing means 74 so that the mnning surfaces 70 of the wing rail sections 46 are elevated slightly above the mnning surface 72 of the crossing nose 42 (see Figure 6). -13-

When it is intended that rolling stock should pass through the railway track crossing 40, a points arrangement is operated in a conventional manner to move switch blades to select a desired route for the rolling stock. At the same time, the controllable drive mechanism is operated to displace the actuator arm 64, and hence the actuating member 62, transversely to move the appropriate one of the movable rails 45 from the closed position to the open position. This is best seen in Figures 3, 7 aiid 8 which illustrates the movement of the appropriate movable rail 45 to allow rolling stock to follow the straight route 12 illustrated in Figure 1. The movement of the movable rail 45 opens a groove 54 between the wing rail section 46 and the crossing nose 42 through which the wheel flanges 56a of rolling stock wheels 56 can pass.

As rolling stock approaches the railway track crossing 40, the movable rail 45 that is in the closed position, and along which it is intended that rolling stock should travel, is gradually loaded by the wheels 56 of the approaching rolling stock and is thereby displaced downwardly from the elevated first position shown in Figures 7 and 8 to the second position shown in Figures 9 and 10. As the movable rail 45 is displaced downwardly from the elevated first position to the second position, the convex profile section 80 engages the concave profile section 84 as shown in Figures 9 and 10 and the movable rail 45 is thus locked in the closed position. As the wheelsets of rolling stock pass through the railway track crossing 40, the load applied to the locked movable rail is intermittently reduced, typically for short periods of a few seconds each. During these short periods, the dampers 76 help to prevent the locked movable rail 45 from springing upwardly from the second position to the first position under the action of the biasing means 74.

After the rolling stock has passed ihrough the railway uack crossing 40 and load is no longer applied by the wheels 56 to the locked movable rail 45, the movable rail 45 is biased by the biasing means 74 back to the elevated first position shown in Figures 7 aM 8. The movement of the movable rail 45 from the second position to the elevated first position is retarded by the dampers 76, thereby ensuring a controlled upward movement. Finally, the controllable drive mechanism is operated to displace the actuator arm 64, and hence the actuating member 62, transversely to a neutral position thereby allowing the displaced movable rail 45 to move from the open position shown in Figures 7 to 10 to the closed position shown in Figures 5 and 6 to thereby close the groove 54. The railway track crossing 40 is, thus, returned to the neutral state shown in Figures 2, 5 and 6. Movement of the displaced movable rail 45 from the open position to the closed position may occur due to the inherent stiffness and natural bend of the movable rail 45 and may be assisted by the biasing means 74, The dampers 76 may also help to retard the movement of the movable rail 45 from the open position to the closed position.

In the unlikely event that the railway track crossing 40 should fail when it is in the neutral state with both of the movable rails 45 in the closed position (for example due to failure of some part of the actuator arrangement 60), rolling stock can still safely pass through the crossing 40 without significantly increasing the derailment risk, In this mode of operation, the wing rail sections 46, and hence the movable rails 45, can be displaced transversely by the wheel flanges 56a of passing rolling stock. The railway track crossing 40 thus acts like a conventional "passive" swing wing crossing. The dampers 76 also help to prevent the movement of the movable rail 45 from the open position to the closed position after each wheel flange 56a has passed through the groove 54.

Although extremely unlikely, it is possible that the railway track crossing 40 could fail when set for a particular route but that rolling stock may need to pass through the railway track crossing 40 along the other route. For example, the railway track crossing may be set for the straight route as shown in Figure 3 whereas rolling stock may need to follow the turnout route. As will now be explained, the railway track crossing advaniageously allows rolling siock to Follow ihe correct route without derailment, albeit at much reduced speed, even when the crossing 40 is set for an incorrect route, Referring again to Figure 3, when rolling stock is executing a trailing-point movement along the turnout route in the converging direction of the rails 44 forming the crossing nose 42, the wheel flanges 56a engage the flared section 58 of the closed wing rail section 46 and push it, and hence the movable rail 45, transversely to the open position.

-15 -There wiH, of course, be a gap between the crossing nose 42 and the other wing rail section 46, which has been displaced to the open position by the actuator arrangement 60, that will need to be traversed by the wheels 56. In extreme cases, the wheels 56 may fall to ground or onto a support 43, However, it will be seen from Figure t2 that the upper surface of the actuating member 62 includes ramp sections 63 at longitudinally opposite ends thereof These ramp sections 63 help to re-rail the wheels 56 onto the movable rail 45 that has been displaced to the open position by the actuator arrangement and with which the actuating member 62 is, therefore, in contact.

When rolling stock is travelling in the opposite direction and executing a facing-point movement along the turnout route in the diverging direction of the rails 44 forming the crossing nose 42, the wheels 56 derail and ride down the ramp section 63 of the actuating member 62 before the wheel flanges 56a are captured by the crossing nose 42 and re-lifted to follow the appropriate one of the diverging rails 44.

In all of the scenarios described above in which the railway track crossing 40 is incorrectly set to allow the passage of rolling stock along the desired route, it will be understood that the check rails 34 (see Figure t) ensure that the rolling stock ultimately follows the correct route.

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 replacedby alternative Features serving the same, equivalent or similar purposes, unless expressly stated otherwise.

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 possiNe variations thereof is encompassed by the present invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

Claims 1. A railway track crossing comprising: a fixed crossing nose formed by a pair of diverging rails; a pair of independently movable rails each having a wing rail section provided on each side of the fixed crossing nose, each rail being movable transversely from a closed position in which the wing rail section contacts the crossing nose to an open position in which the wing rail section is spaced from the crossing nose to form a groove that allows the passage of a wheel flange between the crossing nose and the wing rail section; and an actuator arrangement which is operable to move a selected one of the movable rails from the closed position to the open position, each movable rail being arranged to adopt the closed position in the absence of any force applied to it by the actuator arrangement; wherein each movable rail includes a first mating feature which cooperates with a second mating feature to lock the movable rail in the closed position when the movable rail is loaded by the wheels of rolling stock passing through the railway track crossing.
2. A railway track crossing according to claim,wherein each movable rail adopts a first position in which the wing rail section is elevated above the crossing nose when the movable rail is unloaded and each movable rail is arranged to move downwardly to a second position when the movable rail is loaded by the wheels of rolling stock passing through the railway track junction, the first and second mating features being arranged to cooperate when the movable rail is loaded and thereby moved to the second position.
3, A railway track crossing according to claim 2, wherein a running surface of the wing rail section is substantially coplanar with a mnning surface of the crossing nose when the movable rail is loaded and in the second position.
4. A railway track crossing according to any preceding claim, wherein the railway track crossing includes a plurality of biasing means. -18-
5, A railway track crossing according to claim 4 when dependent on claim 2 or claim 3, wherein the biasing means are arranged to bias each movable rail into the elevated first position when each movable rail is not loaded by the wheels of rolling stock.
6. A railway track crossing according to claim 4 or claim 5, wherein the biasing means are aranged to bias each movable rail into the closed position.
7. A railway track crossing according to any of claims 2 to 6, wherein the railway track crossing includes a plurality of dampers, at least one damper being arranged to retard the movement of each movable rail from the second position to the first position.
8. A railway track crossing according to claim 7, wherein the damper is aranged to retard the movement of the movable rail from the open position to the closed position.
9. A railway track crossing according to any preceding claim, wherein the first and second mating features comprise a longitudinally extending concave profile section and a complementary longitudinally extending convex profile section.
10. A railway track crossing according to claim 9, wherein the convex profile section extends downwardly from a lower flange of each movable rail and the concave profile section opens upwardly to accommodate the convex profile section when the movable rail is in the second position.
11. A railway track crossing according to claim 10, wherein the railway track crossing includes a locking element iii which the upwardly opening concave profile section is fonned,
12. A railway track crossing according to according to claim ii, wherein a separate locking element is positioned beneath each movable rail.H, A railway track crossing according to claim 11, wherein a single locking element extends transversely between the movable rails and includes transversely spaced concave profile sections positioned beneath each movable rail.N. A railway track crossing according to any of claims 9 to 13 when dependent on claim 2, wherein the convex profile section arid the concave profile section each include a bearing surface configured to guide each movable rail downwardly to the second position when the movable rail is loaded by the wheels of rolling stock passing through the railway track crossing.15. A railway track crossing according to claim 14, wherein the bearing surface is configured to guide each movable rail upwardly, from the first position to a third position that is elevated above the first position, when the movable rail is moved from the closed position to the open position.16. A railway track crossing according to any preceding claim, wherein the actuator arrangement includes an actuating member positioned between the movable rails, the actuating member being movable transversely to move a selected one of the movable rails from the closed position to the open position.17. A railway track crossing according to claim 16, wherein each movable rail includes a converging rail section which converges between a fixed end and a constriction, the wing rail section diverges from the constriction on each side of the fixed crossing nose towards a free end, and the actuating member is positioned between the converging rail sections.8. A railway track crossing according to claim 16 or claim 17, wherein the actuating member includes a longitudinally extending contoured upper surface having ramp sections at longitudinally opposite ends thereof -20 - 9, A railway track crossing according to any of claims 16 to 8, wherein the actuating member is set to a neutral position out of contact with the movable rails when the movable rails are in the closed position.20. A railway track crossing according to any of claims 16 to 9, wherein the actuator arrangement includes a controllable drive mechanism which is selectively operable to transversely move the actuating member.21. A railway track crossing according to any preceding claim, wherein each wing rail section includes a flared section at its free end which is spaced from the crossing nose when the movable rail is in the closed position.22. A railway track crossing substantially as hereinbefore described and/or as shown in the accompanying drawings.