FIELD OF INVENTION

The present invention relates to signage. The present invention has particular but not exclusive application for signs at or near railway crossings. Reference to signage for railway crossings is by way of example only and the invention is not limited to this example.

BACKGROUND OF THE INVENTION

Many railway crossings particularly those in country areas do not have any signage warning pedestrians and motorists to be careful of trains when crossing the railway tracks. Where there is signage at a railway crossing, it is often a passive sign advising of the presence of the railway crossing.

Active signage is more effective in grabbing the attention of the motorist and pedestrian and making them aware of the presence of the train line. There are also active signs at railway crossings. These active signs often have two flashing red lights that blink alternately when a train is approaching the railway crossing. When these active railway signs are not operational due to power failure or equipment failure, they provide the impression that there are no trains coming along the tracks. This situation is dangerous as motorists and pedestrians believe that they can cross the train tracks without first looking carefully. This problem has led to a number of collisions between cars and trains. Currently there appears to be no suitable solution to this problem. OBJECT OF THE INVENTION

It is an object of the present invention to provide an alternate active sign that in the event of power or equipment failure has a default position that displays a message thereby overcoming at least in part one or more of the abovementioned problems. SUMMARY OF THE INVENTION

In one aspect the present invention broadly resides in an active sign that has a default passive message display, including

sign support means;

active display means which includes an active display screen that can display one or more symbols when the active sign is operational;

activation means to control the display on the active display screen; said activation means receives and processes input to activate the display of one or more lights on the active display screen;

a default passive message display screen that can display a message when the active sign is not operational;

locking means that positions and locks the active display screen in an operative position;

releasing means that changes the position of the active display screen from the operative position and locates the default passive message display screen in the operative position;

wherein when the active sign is operational the active display screen is in the operative position and if the active sign is not operational the default passive message display screen changes to the operative position.

The locking means preferably includes an electric motor to place the active display screen in the operative position and an electromagnetic lock to maintain the active display screen in the operative position. If there is a power failure or a relevant equipment failure, the lock is disengaged and the default passive message display screen is placed in the operative position.

Said releasing means is preferably mechanically operated. Said releasing means can include one or more pivotal shutters. Alternately said releasing means can include a spring that upon release unwinds to present the default passive message display screen in the operative position.

In a preferred form, the default passive display screen is a sign located and maintained in a lower position on the sign support means by operation of an electric motor and solenoid latch. The default passive display screen moves upward by virtue of operationally attached one or more counter weights moving downward under the force of gravity. When the solenoid latch is released the default passive display screen moves to an upper position and covers the active display screen.

The active display screen preferably provides a flashing light display. The lights on the active display screen preferably form symbols such as letters, numbers and animated images. The active display screen preferably provides a high intensity LED flashing message. The flashing lights preferably change in their intensity with respect to the ambient light whether bright sunlight or low light conditions at night. Preferably there is a light sensor to assess the ambient light conditions and provide the assessment as input for the active display screen display.

The active display means preferably includes an audible message or alert.

Preferably the audible message or alert is or includes alarm bells.

The input is preferably from a remote transmitter means. The transmitter means preferably includes a transceiver, transponder or a transmitter.

The active display means preferably includes processing means which can include a preprogrammed VSD or alternately a processor programmed with a set of instructions in response to different types of input.

Preferably the active sign is solar powered. Preferably the active sign is substantially vandal proof and weather proof with the active display means mounted in an enclosed plastic housing.

In a preferred form the active sign is a sign used with a railway crossing to warn a person such as a pedestrian or motorist, of trains on the railway lines.

In the preferred form the input is preferably an RF signal transmitted from an RF beacon mounted on a train and or a wireless signal from a motion detection accelerometer attached to at least one of the rails at or near the railway crossing.

In one form, the active display screen shows an animated high intensity LED message or a conventional flashing lights. The animated message can be a flashing display.

In another aspect the present invention resides in an active sign for use at a railway crossing and that has a default passive message display, including

sign support means;

active display means which includes an active display screen that can display one or more lights when the active sign is operational, said one or more lights forms a flashing signal, a written message or an animated image; activation means to control the display on the active display screen; said activation means receives and processes input to activate the display of one or more symbols on the active display screen, said input is an RF signal transmitted from an RF beacon mounted on a train and or a wireless signal from a motion detection accelerometer attached to at least of the rails at or near the railway crossing;

a default passive message display screen that displays a warning when the active sign is not operational;

locking means that positions and locks the active display screen in an operative position, wherein the locking means includes an electric motor and an electrically operated lock;

releasing means that changes the position of the active display screen from the operative position and locates the default passive message display screen in the operative position, wherein the releasing means includes mechanical means to locate the default passive message display screen in the operative position;

wherein when the active sign is operational the active display screen is in the operative position and if the active sign is not operational the default passive message display screen changes to the operative position.

In one preferred form the active display means includes a screen with an electrically operated shutter system that opens one or more shutters to reveal the active screen surface. Preferably an electric motor can open the one or more shutters and the opened position is maintained by a solenoid lock. If there is a power failure or a failure of relevant equipment, the one or more shutters close by pivoting about an axis of attachment to provide a substantially flush shutter surface displaying a warning message. The substantially flush shutter surface with the displayed warning message forms the default passive message display screen.

In another preferred form the active display means includes an electrically operated blind mounted on two rollers. The electrically operated blind has a cut out portion. Behind the blind is the active display screen and the active display screen is revealed when the cut out portion is in the operative position. When the cut out portion of the blind is in the operative position, the active display screen is in the operative portion. Preferably an electric motor can position the cut out portion of the blind in the operative position and this position of the blind is maintained by a solenoid lock. Preferably at least one of the rollers has an internal torsion spring that is wound up when the cut out portion of the blind is positioned in the operative position. If there is a power failure or a relevant equipment failure, the solenoid lock is released and the wound torsion spring unwinds and forces the cut out portion to move out of the operative position. When the torsion spring is unwound, the blind covers the active display screen. The blind section covering the active screen serves as the default passive message display screen and displays a warning message.

Preferably the high intensity LED message is a diagrammatic representation. of a train engine. More preferably the high intensity LED message is a diagrammatic representation of a train engine that can be orientated facing one way or the other corresponding to the direction in which the train is coming.

The active railway crossing sign is preferably solar powered and self contained. The active railway crossing sign is preferably vandal and weather proof.

The active screen and default screen is preferably mounted within a plastic housing to provide protection against the weather and vandals.

Preferably there is an active railway crossing sign on each side of the railway crossing.

Preferably there is an additional railway crossing sign located 20 to 500 metres from the railway crossing and has an active sign message warning pedestrians and motorists of the nearby railway crossing.

In a further aspect the invention broadly resides in a active railway crossing sign system with at least two active signs as described above and with a first active sign of the at least two active signs positioned near the railway crossing and a second active sign of the at least two active signs positioned remotely warning persons of the nearby railway crossing. The features described in respect of the active signs in the above mentioned aspects of the invention also apply in respect to this aspect of the invention.

In another aspect the invention broadly resides in an active railway crossing sign system including a system control unit that controls one or more active signs proximal to railway tracks (active track roadside sign (ATRS) and one or more active signs a distal from the railway tracks (active early warning sign (AEWS)). The active signs and the system control unit communicate with each other and functionally cooperate to provide a networked system.

The system control unit preferably interacts with and controls one or more active signs proximal to the railway crossing and one or more active signs distal from the railway crossing. The system control unit preferably wirelessly connects to each of the one or more active signs and instructs each of the one or more active signs to flash and sound alarm when a train is approaching. The system control unit preferably determines whether a train is approaching by processing input from one or more of RF signals from a train detection system, detection of a train's RF beacon signal, and satellite and GPS communications.

Preferably a failure in the system control unit will actuate a signal to one or more active signs to display the default passive message display screen.

Preferably each of the one or more active signs includes a microprocessor operationally associated with a light sensor to sense ambient light conditions, dual radio links at different frequencies, a tamper detection system, a solar panel associated with and to charge a battery, current sensors, alarms and alarm controls including flashing lights and sounding bells. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present invention can be more readily understood reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:

Figures 1(a) to (c) are different diagrammatic views of a first embodiment of an active railway crossing sign positioned near the railway crossing;

Figures 2(a) to (g) are different diagrammatic views of a second embodiment of a active railway crossing sign that is positioned remotely from a railway crossing;

Figures 3(a) to (f) are different diagrammatic views of a third embodiment of an active railway crossing sign that is positioned remotely from a railway crossing;

Figures 4(a) and (b) are partial diagrammatic views of a blind for an active railway crossing sign;

Figure 5 is a partial diagrammatic view of the fourth embodiment of the active sign where the default passive message display screen is in the operative position;

Figure 6 is a partial diagrammatic view of the fourth embodiment of the active sign where the default passive message display screen is in an inoperative position;

Figure 7 is a diagrammatic view of an example of an active sign in the operative position of the fourth embodiment;

Figure 8 is a diagrammatic view of the example in Figure 7 where the default passive message display screen is in the operative position; Figure 9 is a diagrammatic view of another example of an active sign in the operative position of the fourth embodiment;

Figure 10 is a diagrammatic view of the example in Figure 9 where the default passive message display screen is in the operative position;

Figure 11 is a diagrammatic overview of the active railway crossing sign system;

Figure 12 is a diagrammatic view of the system control unit; and /

Figure 13 is a diagrammatic view of the active track roadside sign (ATRS) and active early warning sign (AEWS).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In Figures 1 to 3 there are shown different embodiments of the active railway crossing sign where the active sign in Figure 1 is positioned near a railway crossing whereas the active signs in Figures 2 and 3 are positionable 20 to 500 metres from the railway crossing.

With reference to Figure 1 there is shown an active railway crossing sign 10 including support posts 11 , active screen 12 and a solar panel 13. There are additional screens 14 that can be active or passive in providing a message to a person. The active screen 12 has a bold warning "stop on red signal" and a set of lights that flash red alternately when an approaching train is detected. The active screen 12 is visible because a plurality of horizontally disposed shutters 16 are open to show the active screen 12 behind the shutters 16. The shutters 16 are opened by an electric motor powered by electricity from the solar panel 13. When there is power, the shutters 16 are opened. The shutters 16 are kept open by a solenoid lock. If there is no power or a relevant equipment failure, the solenoid lock is released and the shutters 16 close. The closed shutters 16 present a substantially flush surface 17 on which there is a passive sign warning a person to look out for trains. When there is no power or when the equipment fails so that the shutters 16 close, the active sign continues to provide a warning alerting persons of trains travelling on the railway lines. The additional screens 14 alert a person that there are two tracks and provide the standard symbol for a railway crossing.

With reference to Figure 4 there is shown a blind 20 which can be used as an alternate mechanism to shutters. Figures 4(a) and (b) show a blind screen 21 with two rollers 22 which maintain the blind in a taut position. At least one of the rollers 22 is associated with an electric motor to provide a positive drive to keep the blind 20 in a taut position. The blind screen 21 is preferably made of mylar or like polyester sheets that are relatively inert, that cannot shrink with moisture or be stretched. The blind screen 21 has a cut out portion 23 where a portion of the mylar material has been removed. In use, the blind 20 is positioned in front of the active screen and when the cut out portion 23 is positioned in the operative position, the active screen can be viewed by a person. There is also a solenoid lock that maintains the cut out portion 23 in the operative position. At least one of the rollers 22 has an internal torsion spring that is wound when the cut out portion 23 is positioned in the operative position. If there is a power failure or a failure of the lock or electric motor, the solenoid lock is released and the cut out portion 23 is removed from the operative position by the unwinding of the torsion spring. A section of the blind screen covers the active screen preventing a viewer from seeing the active screen. This section of the blind has a passive message sign with suitable words or images on the outer surface of this section of blind screen. The passive sign is a default sign that warns a person of approaching trains or that they are approaching a railway crossing.

With reference to Figures 2 and 3, there are two different embodiments for remotely positioned active railway crossing signs. With reference to Figure 2, there are a series of diagrammatic views showing how the active sign works when an approaching train is detected. In Figure 2 there is shown an active sign 30 having an active screen 31 that has shutters 32. The active sign 30 also has a solar panel 33 to provide electricity to the electric motor and solenoid lock. The active screen 31 and solar panel 33 are mounted on a post. Figures 2(a) and (e) show an active sign that is operational but with no approaching trains detected. When an approaching train is detected the animated train on the active screen 31 becomes a flashing red light (shown in Figures 2(b) and (d)).

An approaching train is preferably detected by motion detection

accelerometer that wirelessly transmits a signal to the active sign 30. Alternately, the approaching train may have an RF beacon which transmits a signal and the signal is detected when the train is in range for the active sign 30 or a central processor which then transmits instructions to the active sign 30.

Where there is a power failure or a relevant equipment failure, the solenoid lock disengages and the shutters 32 close and provide a passive sign 35 on the outer surface of the closed shutters 31. The active sign 30 becomes non- operational. The passive sign 35 warns a person to stop at the railway crossing (shown in Figure 2(c)).

In Figure 3 there is an alternate embodiment of a remotely positioned active sign. In Figure 3 there is shown an active sign 40 mounted on a post 31 and having an active screen 42. The active screen 42 is visible when shutters 43 are opened. The active sign 40 has a solar panel 44 to provide power to the active screen 42. The active sign 40 also has a passive sign 45 indicating the distance of the active sign 40 from the railway crossing. Similar to the embodiment shown in Figure 3, the active signs 40 shown in Figures 3(a) and (f) are operational but there is no approaching train detected. Figures 3(b) and (e) show an active sign 40 that is operational and has an active screen 42 that is a flashing red animated train indicating that there is an approaching train. Figures 3(c) and (d) show an active sign 40 that is not operational and the shutters 43 have closed to display a passive warning sign 46, 47. Passive warning sign 46 in Figure 3(c) shows the symbol for a railway crossing while the passive sign 47 in Figure 3(d) is an alternate embodiment that displays a warning for a person to look out for trains.

With reference to Figures 5 to 13, there is shown another and preferred embodiment of the active railway crossing sign. The embodiment consists of a system that includes a system control unit (SCU), active track roadside sign (ATRS), active early warning sign (AEWS) and roadside sign programming unit (RSPU).

The system has a distributed structure where by all major functions are directly controlled by microprocessors that are under the control of a higher level system controller SCU. This approach provides for ease of functional verification and testing along with the greatest operational certainty which is paramount for this application.

All systems will communicate within their own entities to their own periphery via SPI communication and will communicate between entities. That is SCU and ATRS and AEWS will communicate via dual radio transceivers operating on different spectrum space and will operate on a fully acknowledged based bi directional protocol.

Figure 1 provides an overview of the system where the SCU 50 receives input from the train detection system 51 and other (if any) train detection system 52. The SCU 50 sends signals to the AEWS 53 and ATRS 54 via their respective dual radio links 55. The radio links 55 also receive signals from the train GPS beacon. The RSPU 56 is a processor capable of receiving and transmitting RF signals. An approaching train is detected by the train detection system 51 , typically a motion detection accelerometer, and wirelessly transmits a signal to the SCU 50. An approaching train often has an RF beacon which transmits a signal. The RF signal is detected when the train is in range for the AEWS 53, ATRS 54 and or the SCU 50. If the SCU 50 detects the RF signal it transmits instructions to the AEWS 53 and ATRS 54.

The SCU is a base controller of up to 8 signs (4 x ATRS and 4 x AEWS). It continuously monitors inputs from a train detection system for both its health (by virtue of a heart beat pulse) and alarm input of an incoming train. This input is flexible in its implementation to handle any form of unique input stimulus required. The SCU continuously monitors its own health, and health of all signs commissioned with it by virtue of continuous interrogation of all core and periphery electronics. It is a solar sourced, battery powered enclosed control system with dual radio

transceivers operating on different spectrum space for communication to and from all signs. It will communicate to the Back End Controller (BEC) system via terrestrial or satellite wireless communication in which it can alarm and supply requested or periodic logging data via the uplink or receive data to act on or files to enable over the air firmware updates for all entities within its system.

The functionality of the SCU will operate in three distinct modes. In normal mode, the SCU actively monitors its input and continued presence (Heart Beat) of a train detection system as mentioned above. The SCU actively monitors the health of active roadside signs by way of periodic heart beat wireless bi-directional

communication with same. Fail to safe mode is entered under the four following scenarios:

1. If the SCU detects a loss or failure of the train detection system it will then send a message to all of the signs to switch to passive sign display (failsafe) and report fault back to the BES.

2. If the SCU fails to get a response from any of the signs then the SCU will send a message to all signs to switch to the passive sign display and will report back to the BES.

3. If the SCU's detects a serious fault in it's or the signs electronic periphery besides the radios the SCU will send a message to all signs of the same type to switch to the passive sign display and report back to the BES. 4. If the SCU or Active Signs detect a tamper or physical damage event.

The SCU returns to normal mode from safe mode under the three following scenarios:

1. Whilst in failsafe mode and the event causing this occurrence has been cleared and the system is able to switch back to normal mode, then the SCU will advise all signs to switch to normal mode. The signs upon receiving such command will reset to active mode state (normal mode).

2. The internal sign control will actively measure the battery charge level and will only indicate that it is ready to switch back to active mode when there is sufficient charge in the batteries to allow for effective continuous operation in which case the SCU will instruct the signage to switch back to normal mode instruct the BEC it has done so.

3. In the event that a sign has been instructed to go to failsafe mode by the BEC and is subsequently instructed by the system to return to normal mode the SCU will instruct the signs to do so.

The SCU comprises the following hardware elements and subsystems: an embedded low power Cortex M3 ARM microprocessor system; external watchdog SPI, multiple serial I/O (SPI); a solar panel; a nickel metal hydride battery; a battery monitoring circuit; wireless 1 (915-928MHz frequency hopping); wireless 2 (433 MHz frequency hopping); GPRS Data packet modem; GSM; WCDMA; 3G; satellite modem which is ip capable; battery charger, sealed enclosure IP66; antennae; power management system; generic interface port to facilitate interface to individual train detection systems; and flashing amber LED.

Figure 12 provides a diagram of the SCU 60 where the cortex M3 processor 61 is operatively associated with two radio links (at approximately 900MHz and approximately 433MHz) 62; 3G/GSM modem and satellite transceivers 63 and 64 respectively; train detection processing 65; three axis accelerometer and tamper switch 66; light sensor and controls 67; battery, battery gauge, solar cells and solar charger 68. The three axis accelerometer can detect whether the SCU has been tampered with and if so a signal is sent and the system defaults to non-active safe mode.

The active track roadside sign has both visible and audible alarms. The ATRS continuously monitors its own health by continuous interrogation of all core and periphery electronics and report to the SCU any failures if able to do so. It continuously receives and transmits a heart beat pulse across both radios to supply the SCU with its required information for its decision making processes as described above. It will fall back to its passive mode upon either being actively instructed to from the SCU or by the passive fail safe mechanical means. It falls back to fail safe mode in the event of:

1 ) Low power detect from battery or loss of battery power.

2) Loss of heart beat from SCU after three heartbeat ticks on both radios.

3) Reduction of LED operation below set level or complete loss.

4) Reduction of audible operation below set level or complete loss.

5) Tilt or rotation of the ATRS sign body.

6) Tamper alarm of the ATRS sign body.

7) Loss or reset of core electronic functionality.

The fail to safe mechanism is by way of an auxiliary face panel that advances up in front of the standard sign face. The drive mechanism for raising the panel is by way of two weighted counter balances.

The mechanism for returning the failsafe panel to it's active position is a magnetic latch lead screw arrangement. The panel is held in the active position by a driven electro magnet. This magnet when not charged releases the panel.

It is a solar sou reed, battery powered enclosed control system with dual radio transceivers operating on different spectrum space for communication to and from all signs. It has dual radio transceivers operating on different spectrum space for communication to and from the SCU.

The function of the active early warning sign is to provide a visible alarm to the motorist of the approaching railway crossing but at a greater distance from the railway crossing than the ATRS. The AEWS continuously monitors its own health by virtue of continuous interrogation of all core and periphery electronics and report to the SCU any failures if able to do so. It continuously receives and transmits a heart beat pulse across both radios as to supply the SCU with its required information for its decision making processes as described above. It will fall back to its passive mode upon either being actively instructed to from the SCU or by the passive fail safe mechanical means. It will fall back to fail safe mode its own accord in the event of:

1 ) Low power detect from battery or loss of battery power.

2) Loss of heart beat from SCU after three heartbeat ticks on both radios. 3) Reduction of LED operation below set level or complete loss.

4) Tilt or rotation of the AEWS sign body.

5) Tamper alarm of the AEWS sign body.

6) Loss or reset of core electronic functionality.

The fail to safe mechanism is by way of an auxiliary face panel that advances up in front of the standard sign face. The drive mechanism for raising the panel is by way of two weighted counter balances. The mechanism for returning the failsafe panel to it's active position is a magnetic latch lead screw arrangement. The panel is held in the active position by a electro magnet. This magnet when not charged releases the panel .

AEWS is a solar sourced, battery powered enclosed control system with dual radio transceivers operating on different spectrum space for communication to and from all signs. It has dual radio transceivers operating on different spectrum space for communication to and from the SCU.

The ATRS and AEWS comprises the following hardware elements and subsystems: an embedded low power Cortex M3 ARM microprocessor system; external watchdog SPI; multiple serial I/O (SPI); a solar panel; a nickel metal hydride battery; a battery monitoring circuit; Wireless 1 (915-928MHz frequency hopping); Wireless 2 (433 MHz frequency hopping); GPRS Data packet modem; GSM; WCDMA; 3G; satellite modem which is ip capable; battery charger with monitor, sealed enclosure; antennae; power management system; motor for setting active mode for sign with sign down detection with motor current monitor; sensors for passive sign position detection; actuator lock for holding sign in active mode with monitor; light sensor for detecting ambient light; LED light units (RED) Qty 2 with monitor; bell/buzzer system and monitor; Tri-axis accelerometer and gyro.

Figure 13 provides a diagram of the ATRS and AEWS 70 where the cortex M3 processor 71 is operatively associated with two radio links (at approximately 900MHz and approximately 433MHz) 72; three axis accelerometer and tamper switch 73; light sensor and controls 74; battery, battery gauge, solar cells and solar charger 75; alarms including sounding bells, flashing lights and their respective sensors and controls 76; electric motor and current sensor for motor 77; solenoid latch and current sensor for solenoid 78 and associated sign down switch 79. As with the SCU, the three axis accelerometer can detect whether the SCU has been tampered with and if so a signal is sent and the ATRS or AEWS defaults to non-active safe mode. The light sensor assesses the ambient light conditions and provides the assessment as input to the microprocessor for use in displaying the active display screen.

Positioning of the passive mode panel is shown in Figures 5 and 6. The same positioning method is used for both AEWS and ATRS. When the active sign (not shown) is displayed, the passive panel 80 is lowered with an electric motor 81and retained in position by an electromagnet solenoid latch 82. The passive panel 80 is lowered via a drive lead screw 85 actuated by the electric motor 81. There are two counter weights 83 suspended by cable 84 on each side of the panel 80 and attached to the panel 80. When the latch 82 is released the panel 80 moves to the top as the counter weights fall towards the ground. The panel 80 covers the active sign. The raising of the panel 80 is mechanical and is not electrically operated.

By way of example two different signs and panels are displayed in Figures 7 and 8 and Figures 9 and 10. Figure 7 shows an active sign 90 with flashing lights 91 whereas in Figure 8 the signage of panel 94 is passive and covers active sign 90. Similarly, Figure 9 shows an active sign 96 with flashing lights 97 whereas in Figure 10 the signage of panel 98 is passive and covers active sign 96.

The RSPU facilitates an interface to allow the installer/ maintenance personal to communicate with the system. The RSPU will interface directly to the SCU to control the complete system and individually to each ATRS and AEWS units to facilitate testing either as a complete system or as individual elements. This interface is battery powered and enclosed in its own IP67 rated housing with dual radio transceivers operating on the same spectrum space for communication to and from the SCU, ATRS and AEWS. The RSPU will allow ease of commissioning and or re-commissioning of the system. From the RSPU the installer/ maintenance personal will be able to test the system to establish the SCU's and network signs health and verify functional operation of complete system whilst maintaining the ATRS and AEWS in failsafe passive display mode. The RSPU is a touch panel industrial grade computer.

The RSPU comprises the following hardware elements and subsystems: an embedded microprocessor system; a lithium-ion battery; Wireless 1 (915-928MHz frequency hopping); Wireless 2 (433 MHz frequency hopping); battery charger with monitor, sealed enclosure IP66; and an antennae. ADVANTAGES

An advantage of the present invention includes providing an active sign warning a person to look out for trains at the railway crossing. Furthermore the active sign provides the advantage that should it be not operational for any reason, there is displayed a passive sign that alerts a person to the railway crossing and/or the possibility of approaching trains. This is an advantage over the current situation where a non-operational sign can provide an incorrect indication that there are no approaching trains. A further advantage of the preferred embodiment of the present invention is that it is self contained in being solar powered and substantially vandal and weather proof thereby avoiding the need for constant regular maintenance.

VARIATIONS

It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

Throughout the description and claims this specification the word "comprise" and variations of that word such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps.