During the leaf fall season in the United Kingdom, and a number of other countries in northern Europe, difficulties are experienced on railway tracks in locations where deciduous trees grow. In particular, vast quantities of fallen leaves settle on or about the railway line, becoming crushed between the rails and the wheels of passing trains and thereby contaminating the rail head with a thin leaf film, similar in slipperiness to Teflon@. Such rail head contamination results in low adhesion between the rails and the wheels of the train, causing poor train acceleration and braking, and also indirectly wheel and rail head damage. Many schemes have been proposed with a view to alleviating the problem, most of which addressed the amelioration of the effects of leaf film on the rail head once this has started to build up, for example using removal solutions and abrasive compounds, but with little success.

Accordingly, it is desirable to provide a device whereby the severity of such problems can be reduced.

According to a first aspect of the present invention there is provided a device for use on railway track, which device comprises at least one air flow deflecting member for mounting alongside a railway rail so as to extend substantially parallel thereto.

According to a second aspect of the present invention there is provided a clip for use in a device embodying the first aspect of the present invention which clip comprises securing means for securing the clip to a railway rail and at least one arm having means for retaining an air flow deflecting member.

According to a third aspect of the present

invention there is provided an air flow deflecting member for use in a device embodying the first aspect of the present invention which air flow deflecting member comprises an elongate blade, the cross-section of the blade being such that when the blade is mounted in its operative configuration alongside a rail an upper edge of the blade is further from the centre line of the rail than a lower edge of the blade.

Reference will now be made, by way of example, to the accompanying drawings, in which: Figs. 1A and 1B show respective front cross- sectional and plan views of a railway rail equipped with a device embodying the present invention; Figs. 2A, 2B and 2C show respective front cross- sectional, plan and side views of a first embodiment of a clip for use in a device embodying the present invention; Fig. 3 shows a front cross-sectional view of a second embodiment of a clip for use in a device embodying the present invention; Fig. 4 shows a front cross-sectional view of a railway rail equipped with another device embodying the present invention; and Figs. 5A and 5B show respective front cross- sectional and side views of a blade for use in a device embodying the present invention.

A device embodying the present invention is shown in Figs. 1A and 1B, the device comprising a plurality of clips 10 (only one shown), for attachment to a foot 31 of a railway rail 30, and a plurality of pairs of air deflecting members comprising blades 20 (only one shown), for attachment to the clips 10 on either side of a head 32 of the rail 30 such that the blades 20 run parallel to the rail 30 at a fixed distance therefrom, the blades being located so as to butt up to, or slightly overlap, one another.

Each clip 10 is intended to be positioned centrally between adjacent rail sleepers. It is designed to be fitted to the rail by hand, remain in place without moving as a consequence of vibration in the track, yet not allow water to become trapped between itself and the rail foot, which would encourage rail foot corrosion, thereby permitting long-term use.

The clip 10 is shown in more detail in Figs. 2A to 2C. The clip 10, which is preferably integrally formed of UPVC or some other semi-rigid, weather resistant thermoplastic material, comprises a rail foot securing base 11 and two vertically-extending blade retaining arms 12. The clip 10 is designed to clip onto the foot 31 of the rail 30 and accordingly the base 11 comprises an under-rail portion lla which extends across the bottom of the rail foot 31 when the clip 10 is in use, each end of the under-rail portion lla being connected to one of the blade retaining arms 12, from which arms 12 there extend respective clip portions lib shaped to define respective recesses for receiving an edge of the rail foot 31. To install the clip 10 on the rail foot 31 the rail 30 is held above the rail foundation, one edge of the rail foot 31 is inserted into one of the clip portions lib, and the under rail portion lla is flexed so as to allow the other of the clip portions lib to be clipped into place on the other edge of the rail foot 31.

A central portion of the under-rail portion lla is formed with a pair of mutually-adjacent shallow depressions llc, separated by a ridge lld, which depressions lie together extend across approximately two-thirds of the width of the under-rail portion lla.

The depressions lie serve as air gaps beneath the rail foot 31, allowing any moisture which might otherwise be trapped between the clip 10 and the rail foot 31 to drain off and/or evaporate, thereby ensuring that the

rail foot 31 is not permanently wet since this would cause corrosion of the rail foot 31. The depressions lie may be of any shape or size and are preferably as large as possible. The ridge lid serves to ensure that the under-rail portion lla does not distort, which would close the air gaps.

The free end of each arm 12 is formed with a snap-fit socket 12a for receiving a blade 20. The arms 12 of the clip 10 may be other than vertical, but if so there may be a risk that the force exerted on an arm 12 when a blade 20 was inserted might unclip the clip 10 from the rail.

The size of the clip will of course depend on the size of the rail with which it is to be used, but by way of example one clip for use in a device embodying the present invention has an under-rail portion lla which is 144mm wide and 120mm long, the depressions lie together spanning 96mm of the width of the under-rail portion lla and being divided by a ridge lid 3mm wide.

Such a clip 10 is formed of material which is approximately 3mm thick, each depression lie being approximately 3mm deep. Each clip portion lib extends inwardly approximately 12mm from the arm 12, each arm 12 being 72mm in length and having a socket 12a 12mm deep and about 3mm wide at its opening.

The clip shown in Figs. 1A to 2C is suitable for use on non-electrified track, overhead line electrified track and for the rail on third rail electrified track which is not adjacent to the electrified third rail.

Since it is undesirable to install a blade 20 between the running rail and the third rail on third rail electrified track, owing to the fact that it would be dangerous to install and could interfere with third rail shoe gear on the trains, an alternative embodiment of the clip is shown in Figure 3. This clip 10'is for use, in track where there is a third electrified rail,

on the rail which is adjacent to the third rail. The clip 10'is identical to the clip 10 except in that one arm 12'is truncated so as to end at the clip portion lib, the clip 10'thereby having only one socket 12a.

Figure 4 shows another device embodying the present invention, incorporating a preferred alternative form of clip 10"having two blade retaining arms 12"which each comprise two interlocking parts, a first part 121 and a second part 122, such that the first part 121 is fixed to the under-rail portion 11 but the second part 122 is removable. The first and second parts 121 and 122 of each arm 12"are shaped so as to have respective elongate members 121a, 122a from which extend, in opposite directions, respective L- shaped members 121b, 122b. Between the elongate member 121a and L-shaped member 121b a snap-fit socket 121c is formed for receiving a free end 122d of the elongate member 122a. Similarly between the elongate member 122a and L-shaped member 122b a recess 122c is formed for receiving the free end 121d of the elongate member 121a. The opposite free end 122e of the elongate member 122a is formed with a snap-fit socket 12a"for receiving a blade 20. Projections 122f are provided on each of the second parts 122, on the side opposite to the L-shaped member 122b, to ensure that the second part 122 is not inadvertently placed during fitting onto the first part 121 in the wrong orientation.

In the same way that the clip 10 can be modified for use on a rail adjacent to a third electrified rail to form the clip 10'shown in Figure 3, the clip 10"of Figure 4 can be modified (not shown) so that there is only one blade retaining arm 12"with a socket 12a".

Figures 5A and 5B show a blade 20 in more detail.

The blade 20 is made from a flexible thermoplastics material with high chemical and biological resistance, such as PP SE50 copolymer. Typically each blade 20 is

3 metres long and is made of material 3mm thick. In one substantially straight edge region 20a of the blade 20 a portion 20b of increased thickness is formed such that that edge region 20a can be snapped into the socket 12a of the clip 10 (10') and then held securely.

As viewed from the side, as in Figures 1 and 5, the blade 20 has a first portion 20c which curves away (outwardly) from the rail 30, for example with a radius of curvature of 30mm, then a second portion 20d which for a short distance curves inwardly, for example with a radius of curvature of 27mm, and then a substantially straight third portion 20e which is inclined with respect to the edge region 20a at an angle of approximately 7.5° (this may vary, for example by 2°).

As an example, the overall length d1 of the blade 20 is approximately 109mm, the length d2 from the free end of the edge region 20a to the beginning of the straight third portion 20e is approximately 55mm and the length d3 of the approximately straight edge region 20a is approximately llmm.

The blade 20 used on one side of the rail 30 is identical to that, if any, used on the other side of the rail 30, only the orientation of the blades 20 on installation being reversed.

The blades 20 provide a barrier to leaves that have a trajectory in the direction of the gap between the rail and rail vehicle wheels.

In particular, when a train moves through the air, complex vortices of air form under and at the sides of the train. These are either rotating in such a way as to move the leaves away from the wheel/rail interface or are rotating so as to move them towards that interface. Leaves that have fallen around the track or have been blown there are picked up by these vortices and some are thereby projected into the path of the wheels.

However, when a rail is equipped with a device embodying the present invention, the blades 20 encourage the leaves to circulate in the vortices that are moving the leaves away, yet deflect those that are in the undesirable vortices, causing them to recirculate.

The blades 20 must be such that when installed they are not close enough to the rail head 32 to be struck by the train wheels, nor must they be so far away as to be ineffective. Desirably, the gap between the blades 20 and the rail head 32 is around 75mm ( 10mm because of the flexibility of the blades 20).

The upper edge of the blade should desirably be between 5mm and 10mm higher than the rail head.

Devices embodying the present invention are easy to install on existing rail track and can be used in almost all locations. When necessary, for example if mechanised tamping, stone blowing, rail grinding, ballast ploughing or the like is to be undertaken, the blades 20 can be easily removed by pulling the blades upwards to unlatch the blades 20 from the sockets 12a on the clips 10. The clips 10 themselves can be left in place in such circumstances, except during rail renewal, owing to the air gaps provided.

It is envisaged that at the end of the leaf fall season the blades 20 will be removed and stored until the following leaf fall season when they will be replaced. The clips themselves can remain in track throughout the year.