TECHNICAL FIELD

This invention concerns a railway safety device and associated method for improving or ensuring the safety of railways, such as for providing an indication of safety or danger to a rail-user. The invention also concerns a railway connector for attachment to a rail fastener.

BACKGROUND

Railways or railroads are used in diverse locations and environments around the world. The rails are often supported on bases and fixed in place to allow vehicles to travel reliably along the rails. For example a conventional railway is typically formed with a pair of parallel rails laid upon a series of railroad ties, also known as railway sleepers. The railroad ties are arranged perpendicularly to the rails, with each of the railroad ties often supporting both of the rails. Generally the railroad ties are either attached to fixed bases or supplemented by ballast to ensure support and a stable alignment of the rails.

Irrespective of the base or support for the rail, for the operation of a vehicle on the rail it is generally necessary to have sufficient clearance at the head of the rail to ensure that a wheel can properly engage the rail. If there is insufficient clearance, then the wheel may not properly engage the rail. Without proper engagement of the rail then the wheel may not adequately grip the rail; and in extreme situations, the wheel may even disengage the rail, potentially causing a vehicle derailment.

A number of factors may contribute to an improper engagement of a rail by a wheel. For example, environmental conditions can lead to accumulations or build-up of material at the rail. The environmental conditions can be weather and location dependent. For example, desert railways can be susceptible to accumulations of sand at the rails, particularly under windy conditions.

To obviate these problems, it would be desirable to provide a safety device to assist in the mitigation or prevention of such improper rail engagements or derailments. The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above. SUMMARY

According to a first aspect of the present invention, there is provided a safety device for a railway. The safety device may comprise a railway safety device for improving or ensuring the safety of a rail user.

The safety device may comprise an indicator to provide an indication to the rail user. The indicator may comprise a visual indicator. The visual indicator may provide or enable a visual measurement by the eye of the user or operator, such as by naked eye. The visual indicator may comprise a display. The indicator may comprise a rail safety guide. The indicator may provide an indication of a condition of a rail associated with the device. The condition may comprise a clearance of a head of the rail. The clearance of the head of the rail may comprise a clearance above material adjacent or directly below the head of the rail. Thus, clearance may be zero clearance or negative clearance. The clearance may correspond to a height between the head of the rail and material below the head of the rail, such as an accumulation of material at the rail. The visual indicator may provide or enable a direct visual measurement of the clearance.

The rail user may be a driver or operator of a vehicle on the railway. For a driver or operator it can be difficult to ascertain levels of accumulations of material, particularly under changeable conditions such as due to wind or other environmental factors. The provision of such a safety device may assist the driver or operator in identifying safe or unsafe rail conditions.

The indicator may be located at or adjacent the rail so as to be directly visible to the rail user, such as when that rail or portion of rail is visible to the rail user. The indicator may be visible simultaneously with the associated portion of rail. The indicator may be fixed relative to the rail. The indicator may be located at a fixed position relative to the rail. The indicator may comprise a gauge, such as a linear gauge. The indicator may comprise a rail clearance height gauge. The indicator may comprise a depth gauge, the depth being indicative of a depth of accumulate material at the gauge. The gauge may comprise a visual feature configured to indicate the condition of the rail by an obscuration of the visual feature by the accumulation of material to a predetermined depth or of a predetermined clearance of the rail. The visual feature may comprise the display, or a portion thereof. The gauge may comprise a mechanical gauge. The gauge may comprise a purely mechanical gauge. The gauge may comprise a static gauge. The indicator may require manual interpretation of the measurement, such as visual measurement by the user. The indicator may provide a plurality of indications of the state of the safety of the rail, each state corresponding to a mode of operation of the railway. The indicator may comprise a "safe use" indicator. The "safe use" indicator may correspond to a minimum height or clearance whereby the associated rail is safe for use, such as safe for use at maximum speed with no additional restrictions. The safety device may be configured such that, in use, the "safe use" indicator is always only visible when there is a safe clearance below a top of the head of the rail. The safety device may be configured such that, in use, the "safe use" indicator is not visible, or not fully visible, when there is no safe clearance. Accordingly, the "safe use" indicator may indicate "danger" or "unsafety" by its absence or lack of visibility.

The indicator may comprise an "unsafe" indicator, corresponding to an unsafe condition of the rail, such as an unsafe clearance below the top of the head of the rail. The "unsafe" indicator may be visible, or may be the only indicator visible, when the condition of the rail is unsafe. Alternatively, the "unsafe" indicator may be only partially visible or invisible when the condition of the rail is unsafe, such as by obscuration by accumulated material of the "unsafe" indicator.

The indicator may comprise a binary indicator. For example, the safety device may be configured to indicate only "safe" and "unsafe". "Safe" may correspond to allowed normal operation of the railway and "unsafe" may correspond to disallowed normal operation of the railway, such as stopping the vehicle, activating a plough or the like, or operation with a reduced speed. Alternatively, the indicator may comprise a ternary indicator. For example, the safety device may be configured to indicate (only) "safe", "less safe" and "unsafe", or the like. The "less safe" indication may correspond to allowed operation in between the "safe" and "unsafe" operation modes (e.g. with a reduced speed intermediate those of the "safe" and "unsafe" speeds). Further alternatively, the indicator may provide additional or multiple indications. The device may comprise an indicator with a total number of indicators corresponding to the total number of operation modes associated with the condition of the rail. For example, a first intermediate mode or indication may correspond to a "reduced speed mode" and a second intermediate mode or indication may correspond to a "plough modes" (e.g. where a sand or snow plough is deployed, such as by the user observing the indicator).

The indicator may comprise a graduated indicator. The indicator may comprise a scale, such as a relative scale, corresponding to an actual height of clearance or accumulation.

The indicator may comprise a colour. The indicator may comprise a colour that contrasts with the surroundings, such as with the rail and/or the railway base/substrate and/or a colour of a likely accumulation material associated with that portion of railway (e.g. yellow sand, brown mud, white snow or the like). The indicator may comprise a plurality of colours, each colour corresponding to a clearance and/or mode of operation. For example, the indicator may comprise a first indicator portion, the first indicator portion comprising a first colour, and the first indicator portion being only visible or only fully visible when there is a safe clearance and a normal or maximum mode of operation is allowed. The indicator may comprise a second portion, the second portion comprising a second colour, and the second portion being only visible or only solely visible when there is no safe clearance and a normal or maximum mode of operation is not allowed. The first and second colours may comprise contrasting colours (e.g. the first colour may be green and the second colour may be red). The indicator may comprise a plurality of contrasting colours. The indicator may comprise a plurality of shades, such as black and grey.

The indicator may be configured to provide daytime indication and/or to provide night- time indication. The indicator may comprise a reflector. The reflector may comprise a directional reflectance, such as aligned longitudinally with the rail so as to increase or improve reflection towards a light source (e.g. a vehicle headlight) on the rail. The indicator may comprise a luminosity. The indicator may comprise a fluorescent and/or a phosphorescent.

The safety device may be bidirectional. The safety device may be configured to provide indications in both directions of travel along the railway. For example, the visual indicator may be double-sided. Alternatively, the safety device may be unidirectional. For example, the safety device may be configured to provide indications only in a single direction of travel, such as for a railway or track where travel is only ever in that single direction. The visual indicator may be single-sided. In a further alternative, the safety device may be multidirectional. For example, the device may be configured to provide indication in both directions of travel along the railway and also laterally, such as for operators, maintenance workers or other observers adjacent the railway. In a yet further alternative, the safety device may be substantially omnidirectional. For example, as well as providing indications laterally and longitudinally, the safety device may provide indication from above. For example, the safety device may comprise a three-dimensional indicator or display, such as one or more spheres. The safety device may be configured for location at a predetermined position relative to the rail. The predetermined position may comprise a predetermined height. The predetermined position may correspond to a predefined clearance. The predetermined position may correspond to a predetermined position of the safety device's display or indicator relative to the rail. The safety device may be configured to position the indicator at a predetermined position relative to the head of the rail. The indicator may provide an absolute indication of clearance of the rail and/or of depth of accumulation. The predetermined position may comprise a predetermined lateral position. For example, the predetermined position may comprise a lateral separation from the associated rail. The lateral separation may provide for the passage of a vehicle along the rail, such as passage without contact or turbulence from a wheel or vehicle part affecting the safety device. For example, the safety device may be configured to be laterally spaced from the rail at a separation of 1cm, 2cm, 5cm, 10cm, 15cm, 20cm, 30cm, 40cm, or any range therebetween. There may be a minimum lateral separation, such as associated with the passage of a vehicle. There may be a maximum lateral separation, such as associated with an indication of actual accumulation at the rail as such (e.g. the closer the indicator to the rail, the closer or more representative the indicator may be of the actual clearance of the rail). The predetermined position may comprise positioning a top of the indicator level with the rail head, such as the top of the rail head. The predetermined position may comprise positioning the top of the indicator below the height of the rail head. Alternatively the predetermined position may comprise positioning the top of the indicator above the height of the rail head (i.e. where the indicator protrudes above the height of the rail). The predetermined position may be dependent upon one or more of: environmental conditions, use of the railway, vehicle, anticipated material for accumulation. For example, for an anticipated accumulation of snow, it may be acceptable for compressible snow to build up above the height of the rail and the top of the indicator may protrude accordingly, whereas for another material (e.g. less compressible), then it may be unacceptable for the material to build up above the height of the rail and the top of the indicator may not protrude. The safety device may comprise a fixed predetermined position. Alternatively, the safety device may comprise an adjustable predetermined position, such as selectable by a user prior to, during and/or after installation of the device.

The safety device may be configured to align the indicator with the rail. The safety device may be configured to align the indicator longitudinally with the rail. The safety device may be configured to resist or prevent rotation of the indicator. The safety device may be configured to maintain an orientation of the indicator, such as in a vertical plane perpendicular to the longitudinal axis of the rail. The safety device may be configured to maintain an orientation of the indicator under anticipated or possible environmental or operating conditions, such as in one or more of: wind; rain; sandstorm; wind or contact from trains, rail maintenance vehicles (e.g. de-icers, sweepers, etc.) or other vehicles; animals; and vandalism. The safety device may be associated with a first side or a second side of the rail, i.e. the predetermined position of safety device may be between or outside of a pair of rails.

The safety device may be configured to return the indicator to a previous position, such as the predetermined position, or orientation upon displacement, such as deviation of the indicator. For example, where a safety device's indicator may be subjected to deformation and/or deflection, such as during ploughing or sweeping of the railway, the safety device may return the indicator to the previous or predetermined position upon cessation of the deflection or deformation.

The safety device may be configured for location outside an anticipated or likely path of a vehicle along the rail. For example, where a plough or sweeper may be deployed on the railway, the safety device may be configured for location outside the path of the plough or sweeper. For example, the safety device may be configured for location on a particular side of the rail; below a particular height relative to the rail; and/or at a particular lateral separation from the rail, related to the path of the vehicle. The safety device may comprise a connector for fixing the position of the safety device relative to the associated rail. The predetermined position of the safety device's indicator relative to the rail may be determined indirectly, such as by the position of the device's indicator relative to the device's connector. The safety device may be configured for indirect attachment to the rail. For example, the safety device may be configured for attachment to a railway support, such as a railroad tie or railway sleeper. The safety device may be configured for attachment to a rail fastener, such as for fastening the rail to the tie or sleeper. The connector may be configured to attach the device to a rail fastener. Accordingly, the predetermined position of the device's indicator may be at least partially determined by the relative position of the rail fastener to the head of the rail. The rail fastener may comprise one or more of: a bolt, a clip, a clamp, a Pandrol™ clamp, a Vossloh™ clamp, or the like. The safety device may be configured for attachment to a rail fastener without affecting the performance or use of the rail fastener. The connector may anchor the device relative to the rail. The connector may be configured to fit onto, into or around the rail fastener. The connector may be configured to provide one or more of: an interference fit; a push-fit; a snap-fit; a twist-fit. The connector may be configured to attach or contact at at least three points, the three points not being collinear such that the connector defines contact or attachment across at least one plane. Accordingly, the connector may be configured to prevent rotation about the connection in at least one direction. The connector may be configured to prevent rotation about the connection in all directions. Accordingly, the connector may be configured to maintain an orientation of the device indicator of the device. The connector may be configured to connect by a user pushing the connector onto, into or around the rail fastener. The connector may be configured to connect by a user rotating or twisting the connector onto, into or around the rail fastener.

The safety device may be attachable to the rail fastener before and/or during and/or after the rail fastener is deployed (i.e. the rail is fastened). The safety device may be detachable from the rail fastener. The safety device may be configured to attach to and/or detach from the rail fastener without affecting or interfering with the rail fastener. The safety device may be configured to attach to and/or detach from the rail fastener without requiring tools. The connector may comprise a flexible spring to provide a force, such as a pre-tension, at the connection to maintain the position of the device when connected. The safety device may comprise one or more springs or resilient members. The connector may comprise a spring. The indicator may be connected to the connector via a spring or resilient member. The indicator may be resiliently connected to the connector. The indicator may be rigidly connected to the connector.

The device may comprise a body portion for positioning the indicator or display relative to the connector, such as longitudinally and/or vertically and/or laterally positioning the indicator or display relative to the connector. The body portion may be rigid. The body portion may be resilient. The body portion may comprise the indicator height adjustment. For example, the body portion may comprise one or more elbows, protrusions or other increments for supporting the indicator at one or more selectable or predetermined heights. The body portion may comprise one or more stems, stalks, pillars, columns or shafts.

At least the connector may comprise a wire material. For example, the connector may be formed from a continuous strip of wire, the strip of wire shaped to form a fit with the rail fastener. It will be appreciated that the wire may be purely mechanical. The wire material may provide a spring force, allowing for deformation or deflection during connection of the device to the rail fastener. The wire material may comprise a cross- section. For example, the wire may comprise a round cross-section, such as for simplifying or enabling forming in multiple directions. Alternatively, the wire may comprise an asymmetrical cross-section, such as a square cross-section, such as to provide resistance to torsion or deflection in one or more directions (e.g. to maintain an orientation of the indicator). Additionally or alternatively, at least portions of the device may be formed by other means or materials, such as by moulding, injection- moulding, sheet-forming, or the like. The safety device may be retrofittable, such as to existing railways. The safety device may be configured to attach to the rail fastener prior to installation of the rail fastener and/or prior to installation of the rail. For example, where the rail is already fastened to a railroad tie as a module or sub-assembly prior to installation at the location of the railway, the safety device may be attached to the rail fastener prior to installation at the location of the railway. The safety device may be configured for repair and/or replacement. For example, where a safety device is damaged or degraded (e.g. due to UV fading or weathering, accident or vandalism), then the safety device, or a portion thereof, may be configured to be removed and optionally replaced. The safety device may be configured to prevent or reduce maintenance or replacement. For example, for deployment in a desert environment, the indicator may comprise a material or coating resistant to sand abrasion.

The safety device may be a permanent safety device. For example, the safety device may be for use along a length of railway where it is intended or necessary to always have a safety device, such as along a length of railway prone or susceptible to periodic accumulations due to weather or other environmental conditions. Alternatively, the safety device may be a temporary safety device. For example, the safety device may be for use along a length of railway where it is intended or necessary to only have a safety device for a limited period, such as along a length of railway for the duration of maintenance works or other temporary operations that could lead to accumulations during the limited period.

The accumulation of material may comprise a natural accumulation, such as due to weather or environmental conditions; and/or a synthetic accumulation, such as due to material deposition during installation, works, or maintenance (e.g. of or adjacent the railway), or from vehicles or operators using the railway. The material may comprise one or more of: sand; mud; water; snow; and leaves, or the like. The safety device may be configured or configurable for use with a particular material and/or particular portion of railway.

The safety device may be sensorless. The safety device may be non-powered. The safety device may provide or enable a non-powered safety system. The safety device may be mechanical. The safety device may be purely mechanical. The safety device may be static in use, such as after installation.

According to a further aspect there is provided a railway comprising the safety device of the first aspect. The railway may comprise a length of one or more of: a railroad; a subway; an underground railway; a tramway; a mountain railway; a desert railway; a funicular railway; a monorail; a tunnel; a bridge; a cutting; and an embankment. The railway may be single-track. That is, the railway may comprise a single track (e.g. a single pair of rails for vehicles supported or propelled along pairs of wheels; or a single rail for a monorail). Alternatively the railway may be twin-track, or more. For example, the railway may comprise two pairs of tracks for the passage of conventional trains or other vehicles with pairs of wheels.

The railway may be bidirectional. For example, the railway may be for use by one or more vehicles travelling in both directions along the railway (e.g. a single vehicle alternately travelling in opposite directions; or first and second vehicles travelling consecutively in opposite directions along the railway). Alternatively, the railway may be unidirectional. For example the railway may comprise a pair of tracks, each track for travel in opposite directions such that each track is only used for travel in a single direction.

The railway may comprise a plurality of safety devices. The plurality of safety devices may be arranged along a length of the railway. The plurality of safety devices may be evenly distributed along the length of the railway, or along portion/s of the length of the railway. The plurality of safety devices may be spaced apart at a predetermined separation. The predetermined separation may be related to or correspond to a maximum safe separation. For example, where a length of railway may be prone or susceptible to an accumulation or settling, the safety devices may be spaced apart along the railway at a predetermined separation that corresponds to a distance less than a distance expected or typically required for an unsafe accumulation. For example, for an accumulation of sand, a particular minimum distance may be required for the sand to accumulate to an unsafe height (e.g. there may be a relationship between height of accumulation and footprint or distance required). The predetermined separation may be related to or correspond to a minimum safe separation. For example, there may be a minimum separation between consecutive safety devices that allows. For example, where consecutive safety devices are placed too close together along a length of railway, a preceding safety device may at least partially obscure a next safety device such that there should be a minimum separation between consecutive safety devices. The plurality of safety devices may be arranged along the railway with a separation significantly less than the maximum separation. The plurality of devices may be arranged along the railway with a separation so as to provide for redundancy and/or a factor of safety. For example, it may be safe for a vehicle to proceed, or to proceed as normal, along a stretch of railway where there is only an incidental "unsafe" clearance or accumulation for a short distance (e.g. where only a single safety device indicates an abnormality or unsafety and the preceding and subsequent safety devices are located sufficiently close by and indicate safety, then there may be circumstances or uses where it may be deemed acceptable for an operator to proceed as normal).

The safety devices may be arranged consecutively along the railway at a similar position relative to a same rail, such as similar lateral positions. For example, the safety devices may be arranged consecutively along a same side or sides of a rail or railway (e.g. right or left, or inside or outside).

Additionally or alternatively, the plurality of safety devices may be arranged consecutively along the railway at dissimilar positions. For example, consecutive safety devices may be arranged at or adjacent alternate rails and/or alternate sides of one or more rails. For example, a first safety device may be arranged at or adjacent a left of a pair of rails and a second safety device may be arranged at or adjacent a right of a pair of rails. Similarly, the safety devices may be arranged on a same or different sides of a single rail (e.g. on an inside or an outside of a single rail of a pair).

At least some of the plurality of safety devices may be arranged at similar longitudinal positions along the railway. For example, a pair or pairs of safety devices may be positioned at similar longitudinal positions along a railway comprising one or more tracks.

According to a further aspect, there is provided a method of improving or ensuring the safety of a railway. The method may comprise providing the safety device of the first aspect.

According to a further aspect, there is provided a railway connector for attachment to a rail fastener. The railway connector may comprise one or more features of the connector or connector portion of the safety device of the first aspect. The railway connector may be for fixing or anchoring a device, such as a safety device, relative to a rail.

According to a further aspect, there is provided a method of connecting a device to a rail fastener. The method may comprise connecting a device to a railway fastener using the connector or connector portion of the first aspect or immediately preceding aspect.

The invention includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. For example, it will readily be appreciated that features recited as optional with respect to the first aspect may be additionally applicable with respect to the other aspects without the need to explicitly and unnecessarily list those various combinations and permutations here (e.g. the connector of one aspect may comprise features of any other aspect). Optional features as recited in respect of a method may be additionally applicable to an apparatus; and vice versa.

In addition, corresponding means for performing one or more of the discussed functions are also within the present disclosure.

It will be appreciated that one or more embodiments/aspects may be useful in indicating a condition of a railway, such as safe and/or unsafe. The above summary is intended to be merely exemplary and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a safety device in accordance with a first embodiment of the invention, the device shown connected to a rail fastener;

Figure 2 is a first perspective view of portion of the device of Figure 1 disconnected from or unconnected to the rail fastener, showing a connector of the device; Figure 3 is a perspective view of an alternative connector;

Figure 4 is a further perspective view of the alternative connector of Figure

3;

Figure 5 is a perspective view of a portion of the connector of Figure 3, the connector shown connected to a rail fastener;

Figure 6 is a perspective view of the device and rail fastener of Figure 1 , shown positioned relative to rail; and

Figure 7 is a perspective view of a plurality of devices according to Figure 1 shown arranged along a railway. DETAILED DESCRIPTION

Referring to figures 1 and 2, these show an exemplary railway safety device 10 in accordance with the invention, for improving or ensuring the safety of a rail user.

As shown here, the device 10 comprises a rail clearance height gauge with a display in the form of a visual indicator 12, which enables a visual measurement by the eye of the user or operator, such as by naked eye. The indicator 12 provides an indication of a condition of a rail (not shown in Figure 1) associated with the device 10, here the condition being a clearance of a head of the rail. The indicator 12 provides or enables a direct visual measurement of the clearance. It will be appreciated that the indicator 12 shown here is a double-sided indicator, such as for providing bi-directional indications along a single-track railway.

In the embodiment shown here, the indicator 12 provides a plurality of indications of the state of the safety of the rail, each state corresponding to a mode of operation of the railway. The indicator 12 comprises a "safe use" indicator 14, which may have a first colour (e.g. green). The "safe use" indicator corresponds to a minimum height or clearance whereby the associated rail is safe for use at maximum speed with no additional restrictions. The safety device 10 is configured such that, in use, the "safe use" indicator 14 is always only visible when there is a safe clearance below a top of the head of the rail. The safety device 10 is configured such that, in use, the "safe use" indicator 14 is not visible, or not fully visible, when there is no safe clearance. Accordingly, the "safe use" indicator 14 indicates "danger" or "unsafety" by its absence or lack of visibility.

The indicator 12 comprises an "unsafe" indicator 16 corresponding to a dangerous or unsafe condition of the rail, such as an unsafe clearance below the top of the head of the rail. "Safe" corresponds to allowed normal operation of the railway and "unsafe" corresponds to disallowed normal operation of the railway, such as stopping the vehicle. Here, the "unsafe" indicator 16 is or becomes the only indicator visible when the condition of the rail is unsafe. Where the "unsafe" indicator 16 is or becomes the only visible or only fully visible indicator, such as by obscuration of the other indicators 14, 18 by accumulated material, then the user or operator may read the safety device 10 as indicating an unsafe condition. Accordingly the user can take appropriate action, such as stopping the vehicle. The unsafe indicator 16 shown here has a contrasting colour (e.g. red) to that of the safe indicator 12.

Here, the indicator 12 comprises a ternary indicator, with an intermediate indicator 18 corresponding to a "less safe" condition. Accordingly, the safety device 10 is configured to indicate "safe", "less safe" and "unsafe". The "less safe" indication corresponds to allowed operation in between the "safe" and "unsafe" operation modes (e.g. with a reduced speed intermediate those of the "safe" and "unsafe" speeds, activating a plough or the like, or operation with a reduced speed). Here, the intermediate indicator has a different colour to the safe and unsafe indicators 14, 16, such as an orange or amber colour. It will be appreciated that, in uses, the device 10 indicates a "less safe" condition when the safe indicator 14 is not visible, such as obscured by accumulated material, but the intermediate indicator 18 (and the unsafe indicator 16) are visible.

The safety device 10 is configured for location at a predetermined position relative to the rail, including a predetermined height of the indicator 12 corresponding to a predefined clearance of a head of the rail. The indicator 12 provides an absolute indication of clearance of the rail and of depth of accumulation. Here, the predetermined position also comprises a lateral separation from the associated rail, providing for the passage of a vehicle along the rail, such as passage without contact or turbulence from a wheel or vehicle part affecting the safety device 10 (or vice versa). The predetermined position of the safety device's indicator 12 relative to the rail is determined indirectly by the position of the device's indicator 12 relative to the device's connector 20. The safety device 10 is configured for indirect attachment to the rail, here being attachment to a railway support, such as a railroad tie or railway sleeper via a rail fastener. Accordingly, the predetermined position of the device's indicator 12 is at least partially determined by the relative position of the rail fastener 22 to the head of the rail. The connector 20 effectively anchors the device 10 relative to the rail, in use. Figure 2 in particular shows the connector 20 of the device 10 for connecting the device 10 to the rail fastener 22, which is a Pandrol™ clip as shown in Figure 1. The connector 20 shown here has a return 24, 26 on each side of a central portion 28, to ensure that the connector 20 acting as a spring does not rock back and forth on the rail fastener 22. The safety device 10 is configured for attachment to the rail fastener 22 without affecting the performance or use of the rail fastener 22. The connector 20 takes up very little space either side of the rail fastener 22, and does not interfere with the other parts of the rail fastener 22. The safety device 10 is configured to align the indicator 12 longitudinally with the rail and to resist or prevent rotation of the indicator 12. The safety device 10 is configured to maintain an orientation of the indicator 12 in a vertical plane perpendicular to the longitudinal axis of the rail.

As shown in Figure 1 , the connector 20 is configured to fit onto and around the rail fastener 22. The connector 20 here is configured to provide an interference fit by pushing the spring portion 28 in between the two springs of the rail fastener 22. The connector 20 is configured to prevent rotation of the device 10 about the connection with the rail fastener 22 in all directions. Accordingly, the connector 20 is configured to maintain an orientation of the device's indicator 12 relative to the rail fastener 22, and consequently to the rail (not shown in Figure 1). As can be appreciated from Figures 1 and 6, the safety device 10 is attachable to the rail fastener 22 before and/or during and/or after the rail fastener 22 is deployed (i.e. the rail is fastened). The safety device 10 is detachable from the rail fastener 22. The safety device 10 is configured to attach to and detach from the rail fastener 22 without affecting or interfering with the rail fastener 22; and without requiring tools. The indicator 12 is connected to the connector 20 via a body portion 30 in the form of a resilient stem member, which is sufficiently rigid to maintain the indicator 12 vertical in normal conditions (e.g. when subjected to wind). The connector 20 and body portion 30 are in a single plane. Rotation of the device 10 in a plane parallel to a longitudinal axis of the rail is prevented by the connection to the rail fastener 22 at at least two points (e.g. both of the rail fastener's 22 springs 36, 38). Rotation of the device 10 in a plane perpendicular to the longitudinal axis of the rail is prevented by the positioning or effective clamping of the connector 20 between a rail fastener body 34 and the springs 36, 38 of the rail fastener 22. It will be appreciated that the device 10 may be connected to the rail fastener 22 by inserting the central section 28 in between the springs 36, 38 of the rail fastener 22 and then turning the device 10 through 90 degrees (to the position of Figure 1), and locking in that space between the springs 36, 38. Although not shown, it will be appreciated that the embodiment of Figures 1 and 2 may be formed from square or rectangular section steel to ensure it locks, using spring pressure.

The safety device 10 is configured to return the indicator 12 to a previous position, such as the predetermined position, or orientation upon displacement or deviation of the indicator 12. For example, where the safety device's indicator 12 is subjected to deformation and/or deflection in use, such as during ploughing or sweeping of the railway, the safety device 10 return the indicator to the previous or predetermined position upon cessation of the deflection or deformation.

Referring now to Figures 3, 4 and 5, there is shown a connector 120 of a safety device 1 10 generally similar to that shown in Figures 1 and 2. Similar features are denoted by similar reference numerals incremented by 100. Accordingly, the device 1 10 comprises a central portion 128 and two return portions 124 and 126. Compared to the embodiment of Figures 2, 3 and 4, it will be appreciated that the connector 120 of Figures 5, 6 and 7 takes up slightly more space than the connector 10 of Figures 1 and 2. The connector 120 comprises a flexible spring to provide a force, such as a pre-tension, at the connection to maintain the position of the device 110 when connected. As shown in Figure 4, the body portion 130 comprises an indicator height setting 132, shown here in the form of an elbow. It will be appreciated that in other embodiments (not shown), the body portion 130 comprises an adjustable predetermined position, such as selectable by a user prior to, during and/or after installation of the device 1 10. Referring now to Figure 6, there is shown a perspective view of the device 10 and rail fastener 22 of Figure 1 , shown positioned relative to a rail 40. As can be seen from Figure 8, the predetermined position comprises positioning a top 50 of the indicator 12 level with the rail head 42, such as a top 44 of the rail head. It will be appreciated that the predetermined position may be dependent upon one or more of: environmental conditions, use of the railway, vehicle, anticipated material for accumulation. For example, for an anticipated accumulation of snow, it may be acceptable for compressible snow to build up above the height of the rail and the top of the indicator may protrude accordingly, whereas for another material (e.g. less compressible), then it may be unacceptable for the material to build up above the height of the rail and the top of the indicator may not protrude.

Here, the clearance of the head 42 of the rail 40 comprises a clearance 50 above accumulated material adjacent or directly below the head of the rail (material not shown). The clearance 50 corresponds to a height between the head 42 of the rail and material below the head of the rail 40.

Referring now to Figure 7, there is shown a perspective view of a plurality of devices 10 according to Figure 1 shown arranged along a railway 60. The indicators 12 of the devices 10 are located at or adjacent the rail so as to be directly visible to the rail user, such as when that rail 40 or portion of rail 40 is visible to the rail user. The indicators 12 are visible simultaneously with the associated portions of rail 40. The indicators 12 are all fixed relative to the rail 40. The railway may comprise a plurality of safety devices. The plurality of safety devices 10 are evenly distributed along a portion of the length of the railway 60. The plurality of safety devices 10 are spaced apart at a predetermined separation that corresponds to a distance less than a distance expected or typically required for an unsafe accumulation and corresponding to a minimum safe separation. Consecutive safety devices 10 are not placed too close together along a length of railway 60, so that a preceding safety device 10 does not obscure a next safety device 10. Here, the safety devices 10 are arranged consecutively along the railway 60 at a similar position relative to a same rail 40. The safety devices 10 are arranged consecutively along a same side or sides of a rail or railway (e.g. the right or inner side of a left rail of a pair or rails on the right-hand side of a twin-track, as shown in Figure 7). For a driver or operator it can be difficult to ascertain levels of accumulations of material, particularly under changeable conditions such as due to wind or other environmental factors. However, the provision here of such a plurality of safety devices 10 assists the driver or operator in identifying safe or unsafe rail conditions. In Figures 6 and 7, the safety devices 10 are shown on the inside of the rail 40, i.e. between a pair a rails 40. It will be understood that the safety devices 10 may be positioned on either side of the rail 40.

It will be appreciated that any of the aforementioned device may have other functions in addition to the mentioned functions, and that these functions may be performed by the same device.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention. For example, it will be appreciated that although shown here as circles, the indicators may comprise other shapes or forms. Similarly, although shown hear as planar, other embodiments of indicators may be curved, such as convex and/or concave.