WO2003016119A1

WO2003016119A1 - Deflector to be mounted adjacent to a trainwheel

Info

Publication number: WO2003016119A1
Application number: PCT/GB2002/003747
Authority: WO
Inventors: Malcolm Higgins; Mike Davis
Original assignee: Laserthor Limited; LEEMING, Catherine; Davis, Andrew
Priority date: 2001-08-14
Filing date: 2002-08-14
Publication date: 2003-02-27

Abstract

The present invention relates to a deflector (20) to be mounted adjacent to a wheel of a train and intended to help prevent the deposition of lightweight objects, and in particular leaves, onto railway tracks. The deflector comprises a trailing portion (40) which is positioned proximal to a contact surface of said wheel and a leading portion positioned distal from said contact surface.

Description

DEFLECTOR TO BE MOUNTED ADJACENT TO A TRAIN HEEL

The present invention relates to an apparatus for a train. More particularly, the present invention relates to a deflector for trains to help prevent the deposition of lightweight objects, and in particular leaves, onto railway tracks.

The problems associated with leaves being deposited onto railway tracks are widespread. The leaves typically fall from trees alongside the railway and as a train passes at speeds upwards of, for example, 65 km/h the vortices created by the train, particularly around the wheel set and track, lift the leaves and draw them into the wheel set. The leaves picked up by the vortices may be forced into the wheel/track nip (hereafter the wheel nip) and become squashed onto the railway track. The squashing of the leaves causes a coating to form on the railway track and, as the coating builds up with the passage of successive wheel sets, it becomes increasingly difficult for the wheels of the train to brake effectively or to find traction when accelerating. Thus, the formation of this coating can present a serious safety problem and can result in delays which are highly undesirable .

The problems outlined above are compounded by the strength of the bond between the track and the coating once it has formed. To remove the coating effectively can necessitate manual scouring of the railway track.

Obviously, this is a highly labour intensive and time consuming process which can itself cause further delays .

Nevertheless, efforts to deal with the problem of leaves on railway tracks have traditionally been directed to looking at different ways of removal. The present inventors have now recognised that the problem may be tackled instead by seeking to prevent or at least reduce the build-up of a coating of leaves and the like on railway tracks.

Viewed from a first aspect there is provided a deflector to be mounted adjacent to a wheel of a train, the deflector comprising a trailing portion which is positioned proximal to a contact surface of said wheel and a leading portion positioned distal from said contact surface. When said train travels in a direction such that said leading portion is in front of said trailing portion, the deflector deflects the airflow away from said contact surface (that is the portion of the outer surface of the wheel which contacts the upper surface of the railway track as the wheel rotates) and, thus, the number of leaves in this critical area is reduced. The airflow off the deflector may also beneficially generate a slight updraft which lifts leaves off of the railway track. The build-up of a coating on the railway track is thereby reduced and the associated problems are ameliorated.

The deflector is preferably arranged substantially to fill the space between the wheel and the railway track adjacent to the wheel nip. Rather than just filling the space adjacent to the wheel nip, it is intended to provide a deflector which actively promotes sideways airflow away from the track.

The trailing portion of the deflector may define a trailing-edge or a trailing surface. The cross-section of the trailing portion of the deflector, viewed in a vertical plane, preferably has a radius of curvature larger than that of the wheel so that a substantially uniform gap is defined therebetween. The gap may be, for example, 5mm, 10mm, 15mm, 20mm, 25mm or 30mm. This gap advantageously allows relative movement between the deflector and the wheel . The leading portion of the deflector may define a leading-edge or a leading surface.

If a leading-edge is defined it preferably has a curved cross-section, viewed in a horizontal plane, to streamline it and to reduce the induced drag.

Streamlining can beneficially accommodate an offset in the oncoming airflow caused, for example, by the train going around a bend or a cross-wind. The leading-edge may have a curved profile, viewed in a vertical plane, but it is preferably rectilinear. Although the leading edge of the deflector may be set at an angle to the railway track, it is preferably substantially perpendicular.

The centre-line of the deflector may be cambered or rectilinear. The deflector has an inner surface and an outer surface and these surfaces may be symmetrical, semi-symmetrical or asymmetric about the centre-line.

The deflector may have a lower edge which is preferably substantially parallel to the railway track to define a uniform gap along the length thereof. The uniform gap between the railway track and the lower edge is, for example, 20mm, 30mm or 40mm.

The deflector may be made of metal or other durable materials, but it is preferably made of a composite material such as polycarbonate with carbon graphite . A composite structure advantageously reduces the weight of the structure and may facilitate more readily the manufacture of more complex shapes. Although it may be pivotally attached to the train, the deflector is preferably rigidly attached thereto.

The deflector is preferably attached at its upper end. Preferably the deflector is attached to the bogie on which the associated wheel is mounted, or an axle box of the associated wheel, to reduce the relative movement between the deflector and the associated wheel . Most preferably, the deflector is mounted on the chassis of the bogie.

If the train has secondary structures, such as side fairings or panels, located in the vicinity of the wheels, the deflector may be attached to these secondary structures or it may be formed integrally therewith.

The deflector may be removably attached so that it may be detached during periods of the year when leaves on the track are unlikely to be a major problem, for example in the Spring and Summer.

Removal of the deflectors also facilitates their maintenance or replacement as required.

An end-plate arranged generally perpendicular to the plane of the deflector may be provided on the lower edge of the deflector. The end-plate may control the airflow around the lower edge of the deflector and/or any vortices shed off the trailing portion thereof. A flange may be provided on the trailing portion of the deflector to extend along a side of the wheel to provide a further mechanical barrier.

In use on a train, a first deflector may be provided in front of a wheel and a second deflector behind the wheel to achieve the same results when the train is travelling in either direction. In the arrangement whereby two wheels are provided as a pair relatively close together on the same side of a train, for example on the same bogie, it may prove sufficient to provide the first and second deflectors in front of and behind the pair of wheels.

In a first arrangement, the deflector preferably has its maximum cross-sectional thickness towards its leading portion. The maximum cross-sectional thickness is preferably 0.25, 0.5 or 0.75 that of the wheel or is substantially the same as that of the wheel. Alternatively, the maximum thickness may be substantially the same as the thickness of the railway track or substantially the same as the contact surface of the wheel . The deflector preferably tapers away from this maximum thickness towards the trailing portion to reduce the induced drag. In this arrangement, the thickness of the deflector is preferably at a minimum at the trailing portion.

In a second arrangement, the cross-sectional thickness of the deflector at the trailing portion is substantially the same as either the thickness of the contact surface, that of the wheel, or of the railway track. The trailing portion of the deflector in this arrangement may match the associated cross-sectional profile of the wheel or contact-surface such that a substantially uniform gap is defined therebetween across the thickness of the trailing portion.

The deflector may be located such that said leading portion and said trailing portion are located in a plane substantially perpendicular to an axis about which said wheel rotates.

Alternatively, the deflector may be inclined about a vertical axis to the plane substantially perpendicular to the axis about which said wheel rotates. Thus, the deflector may have an angle of attack. In this arrangement, a vortex generated off the trailing portion of the deflector so inclined may advantageously transport leaves up from the railway track and away from the area where the contact surface contacts the railway track. The angle of attack of the deflector may be, for example, 3° , 6° , 9° , 12°, 20°, 25°, 30°, 35° or more.

Preferably, the leading portion of the deflector is offset inwardly relative to the trailing portion such that a vortex shed off the deflector extends along the outside of the wheel. Any leaves transported into this vortex may be deflected away from the contact surface. The angle of attack of the deflector, and the relative positions of the trailing and leading portions, may be reversed to reverse the direction in which the vortex extends. The deflector may be twisted along its vertical length to further promote the generation of a vortex.

In the arrangement whereby the deflector is inclined at an angle to the plane perpendicular to the axis of rotation of the wheel, the trailing portion of the deflector may be offset from the contact surface. The gap between the railway track and the lower edge of the deflector may also be increased to, for example, 50mm, 100mm, 150mm, or more. The gap between the trailing portion of the deflector and the contact surface may also be increased to, for example, 50mm, 75mm, 100mm or more. Thus, leaves caught in a vortex generated off the deflector may be transported away from the wheel nip.

More than one deflector may be provided in front of a wheel. For example, two deflectors may be arranged generally in a "V" configuration to deflect leaves and the like to either side of the wheel.

The deflector may be inclined about a horizontal axis parallel to the plane which is perpendicular to the axis of rotation of the associated wheel by, for example, 2° , 4° , 6° , 8° or more.

In an alternative arrangement the deflector comprises an inner surface and an outer surface angularly offset from each other and joined to define the leading portion. The inner surface preferably deflects the airflow along the inside of the wheel and the outer surface preferably deflects the airflow along the outside of the wheel. Thus, the deflector according to this alternative arrangement is generally wedge shaped. The angular offset between the inner surface and the outer surface may be in the range of 0° to 10°, 10° to 20°, 20° to 30°, 30° to 40°, 40° to 50° or greater than 50°. Preferably the inner surface and/or the outer surface are/is concave. By providing a concave surface the transverse component of the resultant airflow is increased and, thus, the deflection of leaves and the like away from the wheel nip may be increased.

The leading portion is preferably arranged to be displaced inwardly of a plane coincident with the inside surface of the associated wheel. Thus, the deflector is preferably arranged to generate a larger transverse airflow from the inside of the track to the outside, than from the outside to the inside. This arrangement advantageously transports leaves and the like away from the other rail and to the outside of the track where there is more space and they are less likely to be re-circulated into the path of following wheels .

Preferably the inner surface is angularly offset from a plane perpendicular to the axis about which the wheel rotates by an angle in the range of 0° to 3°, 3° to 6°, 6° to 9°, 9° to 12°, or greater than 12°. The leading portion is preferably displaced inwardly relative to the trailing edge of the inner surface. Preferably the rear of the outer surface is displaced outwardly of a plane coincident with the outside surface of the associated wheel. By extending the outside surface beyond the plane of the outside of the wheel, leaves and the like deflected outwardly by the deflector are less likely to be drawn back into the wheel nip. Preferably the trailing edge of the outer surface extends beyond the plane of the outside of the wheel by at least one, two, three, four or more times the width of the wheel itself.

Preferably the inner surface extends rearwardly to form the inner surface of a flange which projects alongside at least a portion of the inside surface of the associated wheel . Preferably the deflector has a rear surface joined to the rear of the outer surface. The rear surface provides a mechanical barrier for preventing leaves and the like being drawn in behind the deflector. The rear surface effectively forms the back of the wedge shaped deflector, with the leading portion forming the front . Preferably the rear surface is angularly offset from the outer surface by an angle in the range of 30° to 45°, 45° to 60°, 60° to 75°, 75° to 90°, or greater than 90°. The rear surface may be concave or convex.

Although the rear surface may define the trailing portion of the deflector, preferably a trailing surface is provided between the rear surface and the inner surface to define the trailing portion.

The deflector may comprise an upper region and a lower region. The lower region may have a smaller cross-section than the upper region, when viewed in a horizontal plane, for example, to satisfy Railway Group Standard gauge requirements in the UK.

Preferably, the lower region has a trailing portion having a width substantially equal to the width of the contact surface of the associated wheel . The upper region may not have to meet gauge requirements and may, therefore, have a larger horizontal cross- sectional area than the lower region.

The upper region and lower region may have different cross-sectional shapes, when viewed in respective horizontal planes. For example, the upper region may have a generally triangular or wedge-shaped cross-section, and the lower region may have a trapezoidal cross-section. Preferably the transverse airflow generated by the upper region is greater than that generated by the lower region. The junction between the upper and lower regions is preferably stepped. Preferably, however, the lower region has a lower outer surface which matches a section of the upper outer surface and forms an extension thereof. Preferably the lower region has a lower inner surface which is geometrically similar to the upper outer surface . The lower inner surface preferably deflects the airflow along the inside of the wheel and the lower outer surface preferably deflects the airflow along the outside of the wheel .

Preferably the upper region has a vertical depth of greater than 350mm, 400mm, or 450mm. The vertical depth of the upper region is preferably less than

500mm. Preferably the upper region has a length of greater than 500mm, 600mm or 700mm. The upper region is preferably not longer than 900mm, 1000mm or 1100mm. The width of the upper region is preferably less than 550mm, 500mm, 450mm or 400mm.

Preferably the lower region has a vertical depth of greater than 100mm, 125mm, or 150mm. The vertical depth of the lower region is preferably less than 150mm or 200mm. Preferably the lower region has a length of greater than 500mm, 600mm or 700mm. The lower region is preferably not longer than 900mm, 1000mm or 1100mm. The width of the lower region is preferably less than 200mm, 150mm or 100mm.

Viewed from a further aspect, the present invention also extends to a deflector for mounting adjacent to a wheel of a train to alter the airflow over the wheel to deflect objects away from the wheel. The deflector preferably comprises a trailing portion which is positioned proximal to a contact surface of said wheel and a leading portion positioned distal from said contact surface. The deflector may be inclined at an angle of attack relative to a plane substantially perpendicular to an axis about which said wheel rotates. Viewed from a still further aspect, the present invention extends to a kit of parts comprising a deflector, as described herein, and attachment components to allow the deflector to be retro-fitted to trains.

The arrangements and variations of the deflector outlined above in respect of the first aspect of the present invention may be applied equally to these further aspects of the invention.

References herein to the angular offset of a surface (for example relative to another surface) are with reference to the chord line of a cross-section of the surface, when viewed horizontally. References herein to the inside of the wheel or track refer to the side towards the middle of the track (i.e. between the rails) and vice versa for references to the outside of the wheel or track. Some preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a side view of the deflector according to the present invention mounted on a bogie of a train carriage;

Figure 2 shows a view of the underside of the arrangement of the deflectors shown in Figure 1 ; and Figure 3 shows an end view of the arrangement shown in Figure 1.

Figures 4 shows a side view of the deflector according to a second embodiment of the present invention mounted on a bogie of a train carriage; Figures 5 shows a plan view of the Figure 4 deflector;

Figure 6 shows a front end view of the deflector shown in Figures 4 and 5 ;

Figure 7 shows two deflectors according to the second embodiment mounted on a train carriage; Figures 8 and 9 show side views of the outside and inside respectively of the deflectors according to the second embodiment; Figure 10 shows a front view of one of the deflectors of Figures 4 to 9 in operation; and

Figure 11 shows a front view of two deflectors according to the second embodiment mounted on a train carriage .

A series of leaf deflectors la, lb, lc, Id according to the present invention are shown attached to a bogie 2 of a train carriage 4 (only a portion of which is shown) in Figure 1. The bogie 2 is provided with four wheels, only two of which 6, 8 are shown.

The wheels run on parallel rails 10 (only one of which is shown) having an upper surface 11. The circumferential edge of the wheels which is in running contact with the upper surface 11 is termed a contact surface 6a, 8a herein.

The deflectors la-Id are located in the plane of the wheels 6, 8 and are fixedly attached to the bogie 2 at their upper ends . The deflectors are made of a composite material, such as polycarbonate reinforced with carbon graphite. The shape and mounting of the deflectors la-Id will now be described with reference to the deflector Id on the right hand side of Figure 1.

The deflector Id extends vertically downwardly from the bogie 2 towards the track 10 on which the wheels 6, 8 run. A lower edge 12 of the deflector Id extends parallel to the upper surface 11 of the track 10 such that a uniform gap is provided there between. This gap reduces the likelihood of the deflector Id contacting the track 10, for example due to irregularities in the upper surface 11 thereof, and thus reduces the likelihood of it being damaged. The deflector Id has a rectilinear leading-edge 14 which extends perpendicularly to the upper surface of the track 10. The leading-edge 14 has a curved cross- sectional profile, as shown in Figure 2, to reduce the induced drag. The width of the deflector Id is at a maximum slightly aft of the leading-edge 14 and then tapers to a minimum at a trailing-edge 16. The trailing-edge 16 is profiled such that it follows the associated outer radius of the wheel 8 which the deflector Id is mounted alongside. A uniform gap is provided between the wheel 8 and the trailing-edge 16 to allow for relative movement there between.

The deflector Id is attached to the bogie 2 by a vertically extending bolt 18, although any appropriate mechanical fastening means could be used. A "keyed" locking arrangement (not shown) is provided between the deflector and the bogie to prevent the deflector pivoting about the bolt 18. As shown most clearly in Figure 3, the deflector Id is located vertically above, and in line with, the track 10. The maximum thickness of the deflector also corresponds to the thickness of the upper surface 11 of the railway track 10. In cross section, the deflector Id is symmetrical about its chord C, as shown in Figure 2. This advantageously allows the same deflectors to be reversed for positioning on either side of the train or facing in either direction. If the deflectors are asymmetric they would be handed depending on where they to be mounted and their orientation.

The other deflectors la-lc are generally the same as the deflector Id described above, but the orientation of the deflectors la, lc to be positioned on the other side of the wheels 6, 8 is reversed. The deflectors la-Id are provided on both sides of the wheels, as trains are generally capable of travelling in both directions.

The operation of the deflectors la-Id will now be described in the arrangement whereby the carriage 4 travels along the track 10 in the direction shown by the arrow X in Figure 1. The deflectors lb, Id in front of the wheel 6 and 8 (relative to the direction of motion of the carriage) deflect the airflow around the sides of the lower portion of the wheels 6, 8. Thus, leaves drawn into this region by the vortices generated by the train as it travels along the track are deflected to each side of the upper surface 11 of the track 10. Thus, the leaves are not trapped between the contact surface 9 and the track 10. The deflectors la and lc behind the wheel 6, 8 may advantageously also serve to deflect the leaves away from the railway track for wheels behind them.

In addition to affecting the airflow in the region around the wheels 6 and 8, the deflectors la- Id, and in particular the deflectors lb, Id in front of the wheels 6, 8, provide a physical barrier which prevents leaves and other debris transported from beside the track 10 being introduced ahead of the contact surface 9. Thus, the likelihood of leaves and the like being trapped in the wheel nip is further reduced.

Of course, if the carriage 4 is travelling in the opposite direction to that shown by the arrow X, the deflectors la, lc in front of the wheels 6, 8 relative to the direction of motion of the carriage (i.e. the deflectors on the left hand side of the wheels in Figure 1) deflect the airflow as described above.

A deflector 20 according to a second embodiment of the present invention will now be described with reference to Figures 4 to 11. In describing the second embodiment, like reference numerals will be used for like components referenced in the first embodiment .

As shown in the side view of Figure 4 , the deflector 20 has an upper region 22 and a lower region 24. A step 23 is formed at the junction between the upper region 22 and the lower region 24, as shown in Figure 6. The deflector 20 is attached to the chassis of the bogie 2 at attachment points (not shown) provided on the upper region 22. The total overall dimensions of the deflector 20 are 795mm longitudinally, 442mm transversely, and 605mm vertically.

A plan view of the deflector 20 is shown in Figure 5. The upper region 22 (represented by a continuous line) has a generally triangular, or wedge shaped, profile in cross-section, when viewed in a horizontal plane, with a concave upper outer surface 26 and a concave upper inner surface 28. The upper outer surface 26 and the upper inner surface 28 are angularly offset from each other. An upper leading portion 25 is defined between the upper outer and inner surfaces 26 and 28.

The upper inner surface 28 extends rearwardly to define a flange 32 which lies substantially parallel to the inside surface of the associated wheel 8.

The upper region 22 has an upper rear surface 30 joined to the trailing-edge of the upper outer surface

26. The junction between the upper rear surface 30 and the upper outer surface 26 defines an outside edge 31. An upper trailing surface 27 is provided between the rear surface 30 and the upper inner surface 28. The lower region 24 of the deflector 20

(represented by a dotted line in Figure 5) has a lower concave outer surface 34 and a lower concave inner surface 36 joined to define a lower leading portion 29. The lower outer surface 34 matches a section of the upper outer surface 26 and forms a continuous downward extension thereof (i.e. the step 23 is absent) .

The lower inner surface 36 of the lower region 24 is geometrically similar to the upper inner surface 28, but is inset therefrom (thereby defining the step 23) . The lower region 24 has a lower trailing surface 40 which in cross-section, viewed in a vertical plane, has a radius of curvature greater than that of the wheel 8 to define a substantially uniform gap between the trailing portion and the contact surface of the wheel 8. The arrangement of the installed deflector 20 relative to the associated wheel 8 and the track 10 will now be described. The upper leading portion 25 is displaced inwardly from a plane coincident with the inside surface of the associated wheel 8, and the outside edge 31 is displaced outwardly of a plane coincident with the outer surface of the wheel . The upper and lower inner and outer surfaces 26 and 28, 34 and 36 extend substantially perpendicular to the upper surface 11 of the rails 10. Likewise, the upper leading portion 25, the upper trailing surface 27, the outside edge 31, and the lower leading portion 29 all extend substantially perpendicular to the upper surface 11 of the rails 10.

As the deflector 20 is attached to the chassis of the bogie 2 it may move independently of the wheel 8. A clearance of at least 25mm is provided between the wheel and the deflector 20 in all planes to accommodate any such relative movement .

As shown in Figure 4, a deflector 20 is fitted at the front of the leading wheel 8 and at the rear of the trailing wheel 6 so as to provide the same functionality independently of the direction of travel of the train. The deflectors 20 are handed for fitting to the front and rear of the wheels 6, 8 and to facilitate attachment on the left and right hand sides of the bogie 2.

When the bogie 2 is in motion in the direction represented by arrow X in Figure 4, an airflow is created over the deflector 20. The upper and lower outer surfaces 26 and 34 are arranged such that a transverse airflow is created across the rail head, from the inside to the outside. The transverse airflow deflects leaves and other airborne debris, lifted for example from either side of the railway track by the aerodynamics associated with the train, away from the wheel nip. Thus, the deflector 20 reduces the number of leaves and debris deposited on the railhead.

The curvature of the upper and lower inner surfaces 28 and 36, and the presence of the flange 32, also serves to prevent the introduction of leaves and other debris into the wheel nip. In particular, material initially located between the tracks 10 is deflected down the inside of the wheels 6, 8 and tends to remain in the central region between the tracks, underneath the bogie 2. Tests have been conducted on a train carriage having a set of four deflectors 20 (according to the second embodiment of the present invention) fitted to one of the bogies 2 to determine the effectiveness of the deflectors. The test carriage is shown in Figures 7 to 11.

The tests used pieces of coloured paper to simulate leaves. The simulated leaves were sprayed with water to dampen them prior to each test . The simulated leaves were deposited in batches of 200 between the tracks of the railway, and along the right hand cess of the railway track. The tests were conducted at speeds of 28mph and 40mph, with and without the deflectors 20 fitted for comparative purposes . The movement of the simulated leaves to the left and right cesses and to the central region (the "4 foot" region) were recorded for each of the tests.

The results of these tests showed that the number of the simulated leaves stuck to the railhead when the deflectors 20 were fitted was reduced by approximately 80%. This reduction was primarily due to a lower number of leaves from the central region, between the tracks, moving outwardly and being trapped in the wheel nip. The deflectors also appeared to reduce the number of the simulated leaves caught in an entrained volume of air between the bogie suspension and the wheel . The design of the deflector according to the second embodiment may be modified to change the profile of the deflecting inner and outer surfaces, Changes in the design of the deflector may also be made to improve use of the positive pressure areas as means for deflecting leaves and the like.

Furthermore, the overall size of the deflector may be reduced.

It will be appreciated that the underside of trains in and around the wheels varies considerably for different classes of trains. As such, the components for attaching deflectors according to the present invention may vary considerably for different classes of trains. Furthermore, the size and arrangement of the deflectors themselves may vary for different classes.

Claims

CLAIMS :

1. A deflector to be mounted adjacent to a wheel of a train, the deflector comprising a trailing portion which is positioned proximal to a contact surface of said wheel and a leading portion positioned distal from said contact surface .

2. A deflector as claimed in claim 1, wherein said deflector substantially fills the space between the wheel and the railway track adjacent to the wheel nip.

3. A deflector as claimed in claim 1 or 2 , wherein the leading portion is displaced inwardly of a plane coincident with the inside surface of the associated wheel .

4. A deflector as claimed in claim 1, 2 or 3, wherein the deflector comprises an inner surface and an outer surface angularly offset from each other and joined to define the leading portion.

5. A deflector as claimed in claim 4, wherein the inner surface and/or the outer surface are/is concave.

6. A deflector as claimed in claim 4 or 5, wherein the rear of the outer surface is displaced outwardly of a plane coincident with the outside surface of the associated wheel .

7. A deflector as claimed in claim 4, 5 or 6, wherein the inner surface extends rearwardly to form the inner surface of a flange which projects alongside at least a portion of the inside surface of the associated wheel.

8. A deflector as claimed in any preceding claim, wherein the deflector is generally wedge shaped.

9. A deflector as claimed in any preceding claim, further comprising an upper region and a lower region.

10. A deflector as claimed in claim 9, wherein the upper region and the lower region have different cross-sectional shapes, when viewed in respective horizontal planes.

11. A deflector as claimed in claim 10, wherein, in cross-section, the upper region is wedge-shaped and the lower region is trapezoidal .

12. A deflector as claimed in claim 9, 10 or 11, wherein the junction between the upper and lower regions is stepped.

13. A kit of parts comprising a deflector as claimed in any preceding claim, and attachment components to allow the deflector to be retro-fitted to a train.

14. A train carriage having a deflector as claimed in any of claims 1 to 12 mounted thereon.

15. A train carriage as claimed in claim 14, wherein the deflector is mounted on a bogie of the carriage.

16. A train carriage as claimed in claim 15, wherein the deflector is mounted on the chasis of the bogie.

17. A train carriage as claimed in claim 14, wherein a first deflector is provided in front of the wheels on a bogie and a second deflector is provided behind the wheels on said bogie.

18. A train carriage as claimed in claim 14, 15 or 16, wherein a first deflector is provided in front of an associated wheel and a second deflector is provided behind the associated wheel .