AU690911B2 - Railway work-site warning system - Google Patents

Description

1-

AUSTRALIA

Patents Act 1990 JOHN MALDEN ELLIOTT and BRADLEY DAMIEN DONOVAN

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Railway Work Site Warning System The following statement is a full description of this invention including the best method of performing it known to us:- -I i Il r II L ss~l I -2- Field of the Invention The present invention relates generally to railway signalling systems and, more particularly to a transportable apparatus for providing a warning of an approaching train, or to enable railway personnel to control the movement of trains.

Background of the Invention Traditionally, when railway maintenance workers upgrade or repair railway lines, a temporary signalling system is put into place at the work-site. This temporary system comprises several components. Firstly, it includes detonators placed on the railway line for providing easily audible explosions to warn the workers when a train approaches. Secondly, the temporary system includes a team of signallers who use flags to control the movement of trains through the work-site. This temporary system is labour intensive, and is therefore expensive to operate.

In addition, it is prone to human error.

To reduce the cost of the temporary signalling 20 system, there is a need for such a system which can *operate automatically or semi-automatically with a minimum of operator intervention such that the team of signallers can be replaced by a small number of operators.

To reduce the susceptibility of the temporary signalling system to human error, there is a need for an automatic system which can operate independently of human intervention in a fail-safe way. In addition, it would be beneficial if such an automatic system undertook regular self-checking procedures and provided an alarm if it 30 detected any fault conditions.

:Systems based on doppler radar have been proposed for detecting the presence of trains and for controlling the movement of trains though the work-site. However, for the following reasons, these systems are unsuitable for use in an urban environment. Systems based on doppler radar may Ir M 0r I I 3 not be able to distinguish between trains and other moving objects. In an urban environment, there may be many moving vehicles other than a train of interest, and a radar-based system may produce false alarms. If many false alarms are generated, workers may begin to ignore them, and this can compromise safety. Systems based on doppler radar may not have a detection region which is sufficiently narrowly focused. This is particularly important when a train is approaching on one line in a set of multiple railway lines which lie side-by-side around a curve, and workers need to know which one of those lines is being used by the train. In addition, systems based on doppler radar are expensive, may not be able to detect the approach of trains around a blind curve, and may not be able to perform self-checking procedures to ensure safe and correct operation.

To overcome the problems associated with systems based on doppler radar, there is a need for a system which is inexpensive, which can detect the presence of trains 20 and ignore other moving vehicles, whose detection can be .restricted to a small predetermined region, and which can perform self-checking procedures.

Another problem is that rails used in Australia have differing dimensions, there being three commonly used oooo 25 types. As such, it is difficult to have a mounting arrangement for a wheel detector which allows for variations between the rail types and which still accurately locates the wheel detector relative to the rail.

Summarv of the Invention 30 The present invention consists in a tr etection and signalling apparatus comprisl train wheel dete means for providing a detection signal w wheel of a train is within a predetermined gion; -F kA' kL /TC(k w ~-PT C 1 Summary of the Invention The p~resent invention consists in a miounting device for use in positioning a wheel detector on a rail which has a bottom flange, an upright web and an upper rail portion, the mounting device including: attachment means for attaching the device against the upright web and between the bottom flange and an underside of the uipper rail portion of the rail: a support platform to, in use, support one or more train wheel detectors, the support platform being mounted on the attachment means so as to be vertically movable thereon; and biasing means acting between the attachment means and the support platform to urge the support platformx, in use, upwardly relative to the attachment means, 15the arrangement being such that upon the attachment means being positioned on the web of a rail the biasing means will urge the support means into contact with the underside of the -upper rail portion of the rail and thus position a train wheel detector on the support platform in a predetermined relationship with the path of a train wheel passing along the rail, 20The invention further consists in a train detection and signalling apparatus including: :*~.:train wheel detection means for providing a detection signal when a wheel of a train is within a predetermined region; a central processing unit, responsive to the detection signal and responsive to commands from an operator, for providing a control signal; a train presence indicator, responsive to the control signal, for inidicating whether the train is withmin a predetermined control area; and a imounting device for use ini positioning the train wheel detector according to the present invention.

4 a central processing unit, responsive to the detection signal and responsive to comm rom an operator, for providing a con signal; and a train presen *ndicator, responsive to the control signal, ndicating whether the train is within the edetermined control area.

The train wheel detection means may detect the presence of the wheel magnetically, electrically, mechanically, or optically.

Preferably, the train wheel detection means comprises a magnetic proximity detector mounted to a rail along which the wheel of the train is to run.

Preferably, the predetermined region can fit within a sphere having a radius of ten centimetres.

Preferably, the train wheel detection means further comprises a status checking means, the central processing unit intermittently polls the status checking means to determine the status of the train wheel detection means, and the central processing unit generates an alarm signal 20 when the status checking means determines that a fault S. exists in the train wheel detection means.

Preferably, the train detection and signalling apparatus further comprises at least two train wheel detection means spaced apart along a stretch of rail, the 25 first detection means defining an outer advance post and the second detection means defining an outer departure post; the advance and departure posts delimiting the control area; and wherein, in use, when a train wheel is detected at the advance post and is subsequently detected S 30 at the departure post, the control signal provided by the central processing unit will cause the train presence indicator to indicate that a train is within the control area until a detector signal is received from the detection means at the departure post.

5 The present invention further consists in a mountin device for use in positioning a wheel detector prox j'te a rail, the rail having a bottom flange, an uprih web and an upper rail portion, the mounting device omprising: attachment means to locate the d ice in a predetermined position relative the upper rail portion of the rail; a support platform in use, support one or more train wheel detect s, the support platform being mounted on the attac nt means so as to be vertically movable away fro n uppermost position; and biasing means acting between the attachment means nd the support platform to urge the support platform towards the uppermost position.

Preferably the attachment means is in the form of a base member with one or more magnets mounted thereto so 'that the base member can be releasably secured to the rail against an outside of the upright web and between the bottom flange and the upper rail portion.

20 Preferably, there are two magnets spaced apart along .".the base member which is elongate.

The base member may further comprise cover means for each magnet, the cover means being in the form of a magnetic flap movably mounted to the base member so as to 25 be movable between an in-use position covering the magnet and an out-of-use position allowing the magnet and the device to be positioned against the rail. Further, the base member is preferably made from a non-magnetic material.

30 Preferably, the flaps are pivotally connected to a .i non-magnetic connector member which is in turn pivotally connected to the base, the pivot axes of the connections being generally parallel to a rail contact surface of the magnets so that the flaps can be positioned flat against the contact surface of the respective magnets.

6 The support platform is preferably in the form of a non-magnetic U-shaped channel, and the base member is preferably in the form of an angle, with bottom portions of the support platform and the base member being positioned so as to face one another; wherein movement of the support platform relative to the base member is guided by at least one guide in the form of an upright guide post fixed to the bottom portion of either the base or the support platform and extending through a hole provided in the bottom portion of the other one of the base or support platform, the guide post having an end stop towards an outer end thereof which defines the uppermost position of the support platform; and wherein the biasing means is in the form of a helical spring which receives the guide post and extends between and bears against the bottom portions of the base and the support platform.

Preferably, there are three guides, two of which are in the form of the above defined guide posts which are spaced apart along the device, with each guide post having 20 a helical spring to bias the support platform into the S. uppermost position; and wherein the third guide is in the form of a pin mounted to the support platform intermediate the guide posts, the pin extending laterally outwards to one side of the support platform and through a vertically 25 extending slot in the upright portion of the base member, and wherein the pin has an enlarged head at its end which is spaced a predetermined distance away from the one side of the support platform sufficient to receive the upright .ide portion of the base member therebetween.

30 Preferably, the mounting device further comprises a location checking means in the form of one or more proximity sensors mounted on the support platform wherein, in-use, the sensors are to be positioned immediately beneath and bear against an overhang of the upper rail portion of the rail and serve to detect whether the 7 support platform is in the correct position relative to the rail.

In use, the mounting device is positioned against one side of the upright web of the rail with an upper edge of the one side portion of the support platform being biased by the biasing means into contact with an underside of the upper rail portion of the rail. In this regard, the present inventors have recognised that the cross-sectional design of the three different rail types used in Australia, while sharing a similar basic design, in fact vary quite significantly in their proportions. For example, the vertical spacing between the overhang of the upper rail portion and the bottom flange can be quite different. It has been found, however, that the extent of the overhang of the upper rail portion from the upright web does not change significantly from one type of rail to another. As such, the mounting device has been designed so as to accurately locate the support platform so that its one side will be positioned immediately underneath the *20 overhang of the upper rail portion, and whereby the vertical movability of the support platform and the biasing means is used such that one side portion of the support platform will always be caused to bear against the overhang. In this way, the train wheel detectors, when 25 mounted to the support platform, will, in use, be positioned in generally the same position relative to the upper portion of any rail type despite variations in the .dimensions of the different rail types.

Brief Description of the Drawings 30 Features and advantages of the present invention will :become apparent from the following description of exemplary embodiments of the invention with reference to the accompanying drawings, in which: Figure 1 is a schematic representation of a temporary railway signalling system in which the present invention I a 8 may be used; Figure 2 is a simplified schematic block diagram of signalling apparatus in accordance with the present invention; Figure 3 is a simplified schematic block diagram of a work-site controlling apparatus in accordance with the present invention; Figure 4 is a schematic block diagram of a driver wake-up apparatus in accordance with the present invention; Figure 5 shows a simplified flow chart which describes the operation of the train detection and signalling apparatus of the present invention when it is in an open mode; Figure 6 shows a simplified flow chart which describes the operation of the train detection and signalling apparatus of the present invention when it is in a warning mode; Figure 7 shows a simplified flow chart which describes the operation of the train detection and 20 signalling apparatus of the present invention when it is in a controlling mode; .Figure 8 shows a simplified flow chart which describes the operation of the train detection and signalling apparatus of the present invention when it is 25 in a possession mode; Figure 9 shows a configuration in which the work-site covers a more complicated railway network; and Figure 10 is a top plan view of a mounting device in accordance with the present invention for use with the train detection and signalling apparatus for quickly and easily securing a wheel detector to a rail.

Figure 11 is a front elevational view of the mounting device of Figure Figure 12 is a cross-sectional view of the mounting device of Figure 11 taken along line 1-1 9 Figure 13 is a cross-sectional view of the device of Figure 11 taken along line 2-2.

Figure 14 is a rear elevational view of the device of Figure Figure 15 is a schematic representation of the display of a control panel for use with the present invention.

Figure 16 is a schematic representation of the present system for detecting/controlling trains in a control area comprising two rail tracks.

Detailed Description of the Preferred Embodiments Figure 1 illustrates a simple configuration in which the train detection and signalling apparatus can be used.

In this configuration, trains travel along railway line 100 in the direction from end 101 to end 102.

Between ends 101 and 102 is work-site 103 in which workers perform maintenance or other tasks on railway line 100.

Some of the main objectives of the train detection and signalling apparatus are to detect the approach of a train along railway line 100, to provide warning to workers in work-site 103 of the approach of the train, and to enable automatic or operator-assisted control of the progress of the train through work-site 103.

Control area 104 defines the region in which the 25 train's location is monitored and possibly regulated.

Control area 104 extends from outer advance post 105 to outer departure post 106. Posts 105 and 106 may be located at any convenient and safe distance from 2. work-site 103, but typically post 105 is located approximately 2.5 km before work-site 103, and post 106 is '"located approximately 2.5 km beyond work-site 103.

Between outer advance post 105 and work-site 103 is inner advance post 107, located typically 1 km from work-site 103.

Figure 2 is a sinplified schematic block diagram of s II -I 10 signalling apparatus 120 which may be present at any one of posts 105, 106, or 107. The signalling apparatus 120 at each one of posts 104, 106, and 107 may comprise a processing unit 121, one or more wheel detectors 122, one or more visible or audible signals 123, a communications terminal 124, or a combination of these elements.

Processing unit 121 is coupled to detectors 122, signals 1;3, and communications terminal 124. In operation, wheel detector 122 detects the passage of the train wheel and signals this occurrence to processing unit 121 which may, in turn, pass this information to communications terminal 124, and/or operate signals 123.

In addition, processing unit 121 may operate signals 123 in response to instructions which it receives via communications terminal 124. Signals 123 preferably comprise signal lights or a radio or other signal receivable by a receiver within the train driver's compartment of each train.

Located within or close to work-site 103 is work-site controlling apparatus 140 which is illustrated in a simplified block schematic form in Figure 3. Work-site controlling apparatus 140 typically comprises work-site processing unit 141, control panel 142, warning system 143, and work-site communications terminal 144.

25 Work-site processing unit 141 is coupled to control panel 142, warning system 143, and work-site communications terminal 144. Control panel 142 may include switches or other means to control work-site processing unit 141. In particular, it may include means for selecting the mode of operation of work-site processing unit 141, means for controlling warning system 143 via work-site processing unit 141, and means for controlling signals 122. Warning system 143 may include a siren, emergency strobe lights, or an interface to a pocket pager.

LL~ L I I I I 1L Preferably, the train detection and signalling apparatus also includes wake-up apparatus located further away from work-site 103 than outer advance post 105.

Train drivers become accustomed to the routes along which they drive and, therefore, may not be fully attentive along stretches of rail which usually are not controlled by signals. Therefore, it may be prudent to include apparatus which alerts the train driver to the presence of temporary signals which are erected along such stretches.

Wake-up apparatus 150 shown in simplified block schematic form in Figure 4 is intended for this purpose, and comprises wake-up processor 151, wheel detector 152, warning system 153, wake-up communications terminal 154, or a combination of these elements. In operation, wheel detector 152 detects the passage of a train wheel, and passes thi, information to wake-up processor 151 which, in turn, operates warning system 153 and may pass the information to wake-up communications terminal 154.

Warning system 153 may comprise any means for alerting the driver, including gas operated scare guns, sirens, and flashing lights or signal communication with a receiver in each train.

Work-site controlling apparatus 140 together with wake-up apparatus 150 and the signalling apparatus at 25 posts 105, 106, and 107 comprise a preferred embodiment of the train detection and signalling apparatus. Preferably, this embodiment of the train detection and signalling apparatus may operate in several modes, which modes may be S selected from control panel 142 by an operator. These modes typically include an "1pen" mode, a "warning" mode, a "controlling" mode, and a "possession" mode.

*".Figure 5 shows a simplified flow chart which describes the operation of the train detection and signalling apparatus when it is in the open mode. In this open mode, the train detecting and controllinq apparatus I -vr 12 detects the presence of the train but takes no action to control the train or to alert the workers. As illustrated at step 160, when this mode is initiated, all signal lights in signals 123 at posts 105, 106, and 107 are switched to green so that the train driver is not instructed to stop the train. As the train passes the wake-up apparatus, according to step 161, it is detected by wheel detector 152, but no control action is taken.

The train, therefore, proceeds along the line and passes outer advance post 105 and inner advance post 107 where, according to steps 162 and 163, it is detected and, again, no monitoring or control action is taken. At step 164, the train traverses work-site 103 and, at step 165, the train passes outer departure post 106 and the system will be cleared ready for the next train.

Figure 6 shows a simplified flow chart which describes the operation of the train detection and signalling apparatus when it is in the warning mode. In this warning mode, the train detecting and controlling 20 apparatus detects the presence of the train and alerts the workers to the train's presence, but takes no action to S. control the train. As illustrated at step 170, when this mode is initiated, all signal lights in signals 123 at posts 105, 106, and 107 are switched to green so that the 25 train driver is not instructed to stop the train.

P(Alternatively, the green lights may not be installed).

As the train passes the wake-up apparatus, according to step 171, it is detected by wheel detector 152, but no control action is taken. The train, therefore, proceeds along the line and passes outer advance post 105.

According to step 172, the apparatus at this post detects the passage and passes this information via communications terminals 124 and 144 to work-site processor 141 which then instructs work-site warning system 143 to warn the workers of the presence of the train and preferably the 13 location of the train. No action is taken to control the progress of the train which continues to pass the inner advance post 107 where, according to steps 173, it is detected and, again, the work-site warning system alerts the workers to the presence of the train. At step 174, the train traverses work-site 103. At step 175, the train passes outer departure post 106 where the train detection and signalling system will be informed of the departure of the train from the control area 104 and reset in preparation for the passage of the next train.

Figure 7 shows a simplified flow chart which describes the operation of the train detection and signalling apparatus when it is in the controlling mode.

In this controlling mode, the train detecting and controlling apparatus detects the presence of the train, alerts the driver to the presence of temporary signals (ie by the wake-up apparatus 150), alerts the workers to the train's presence (ie by the detection and signalling apparatus 120), and controls the passage of the train through the work-site. As illustrated at step 180, when this mode is initiated, the signal lights in signals 123 S.-o at post 105 are switched to yellow to instruct the driver to proceed with caution, and the lights at inner post 107 are switched to red to instruct the driver to stop. As 25 the train passes the wake-up apparatus, according to step 181, it is detected by wheel detector 152. At this post, warning system 153 alerts the train driver that temporary signals are present. The train proceeds along the line and passes outer advance post 105. According to step 182, the apparatus at this post detects the passage and passes this information via communications o terminals 124 and 144 to work-site processor 141 which then instructs work-site warning system 143 to warn the workers of the presence of the train. In addition, the outer advance post signal lights are switched to red to 14 prevent other trains from entering control area 104. The train should then stop before inner post 107, and the operator can control further progress of the train.

Specifically, the operator can keep the inner post lights red and keep the train at that post, or else the operator may operate control panel 142 to change the lights at inner post 107. If the operator changes the lights, the train continues past post 107 where, according to steps 183, it is detected and, again, the work-site warning system alerts the workers to the presence of the train. At step 184, the train traverses work-site 103.

At step 185, the train passes outer departure post 106 and, at step 186, the train detection and signalling system is reset in preparation for the passage of the next train. If, before step 183, the operator had not changed the inner post lights from red but the train nevertheless passes the inner post, then an emergency situation exists and a work-site alarm is accordingly raised at step 187.

Figure 8 shows a simplified flow chart which 20 describes the operation of the train detection and signalling apparatus when it is in the possession mode.

In this possession mode, the train detecting and controlling apparatus instructs the train driver to stop at each post, and warns the workers if the driver does not 25 comply. As illustrated at step 190, when this mode is initiated, all signal lights are switched to red to instruct the driver to stop. As the train passes the wake-up apparatus, according to step 191, it is detected by wheel detector 152. At this post, warning system 153 alerts the train driver that temporary signals are present. The train proceeds along the line and should stop before reaching outer advance post 105. If, however, the train passes the outer advance post, then according to step 192, an emergency situation exists, the apparatus at the outer post detects the passage of the train and passes 15 this information via communications terminals 124 and 144 to work-site processor 141 which then instructs work-site warning system 143 to activate an emergency alarm. If the train passes inner post 107, then the work-site emergency alarm is activated again.

The open, warning, controlling, and possession modes are merely examples of possible modes of operation in a preferred embodiment. Naturally, many other modes can be defined and the present invention is not limited to use in the above four modes. In addition, the present invention is n',t limited to use on a single direction railway as illustrated in Figure 1. For example, Figure 9 shows a configuration in which work-site 103 covers two railway lines: a single direction line 191 and a two direction line 192. In addition, the work-site 103 is between two other railway lines, 193 and 194. Furthermore, trains can cross from line 192 to line 194. Finally, control area 104 encompasses all four lines 191, 192, 193, and 194. Control of this configuration can be accomplished easily using exactly the same principles as those described above. The only changes which need to be made to the train detection and signalling system is that a eooo suitable number of apparatus 120 should be installed adjacent each railway line, and work-site processor 141 should be programmed to control the work-site 103 as .:.desired.

Controlling apparatus 140, signalling apparatus at posts 105, 106, and 107, and wake-up apparatus 150 are preferably all linked by a communications system based, for example, on the RS422 standard. Communication may take place over radio links, land lines, or any other suitable medium.

The system of the present invention can be extended easily to accommodate more complicated rail networks.

Preferably, in such more complicated situations, work-site e 16 processing unit 141 comprises a series of indicators.

These indicators can be used to display the current positions of any trains on the lines as determined by the detectors, and they may be used to indicate the status of the detectors as determined by the status checking means.

Preferably, the train wheel detection means further comprises a status checking means, the central processing unit intermittently polls the status checking means to determine the status of various parts of the train wheel detection means (ie whether it is in working order) including, for example, the wheel detectors, the rail sensors, the door of the cabinets, the battery state and the communications links. The central processing unit generates an alarm signal when the status checking means determines that a fault exists in the train wheel detection means.

One of the advantages of the present invention is the .ease with which a temporary signalling system can be installed on a stretch of rail. Consistent with this advantage, Figures 10 to 14 illustrate a detector mounting o.**.device 200 for use with the system for quickly and easily securing wheel detector 230 to rail 10 so that .oo• detector 230 can detect passage of a train wheel.

The mounting device 200 is for use in positioning detector 202 proximate rail 10, the rail 10 having a bottom flange 11, an upright web 12 and an upper rail portion 13.

The mounting device 200 comprises an elongate base member 201 which is in the form of an aluminium angle having a bottom portion 202 and an upright side portion 203, a support platform 204 in the form of an aluminium U-shaped channel having upright side portions 205 and a bottom portion 206. The base member 201 is longer than the support platform 204 and the support platform 204 is positioned so that one side I C-l- -~IM 17 portion 205a( i.e. the in-side portion 205a) thereof abuts the upright side portion 203 of the base member 201, and which is in a generally central position along the base member 201.

The base member 201 and the support platform 204 are connected together in such a way as to be movable relative to one another. More particularly, the base member 201 is provided with two guide posts 207, spaced apart along its length. Each guide post 207 extends upwardly from the bottom portion 202 of the base member 201 and are formed by a bolt 208 received through a hole in the bottom portion 202 of the base member 201, a cylindrical sleeve 209 which is received over the shank of the bolt 208 and has a larger diameter than the hole in the bottom portion 202, and an end stop 210 in the form of a washer 210a and a nut 210b threadably received over the shank 208a of the bolt 208 so as to clamp the sleeve 209 between the washer 210a and the bottom portion 202 of the base member 201. The guide posts 207 are received through holes 225 in the bottom portion 206 of the support platform 204, the holes 225 having a smaller diameter than the washer 210. Further, a helical spring 226 is also received over each of the guide posts 207 and is between and bears against the bottom portion 202 of the base member 201 and the bottom portion 206 of the support platform 204 so that the support platform 204 is urged into an uppermost position bearing against the end stop 210.

The device 200 further comprises a guide pin 211 mounted on an underside of the bottom portion 206 of the .".support platform 204. More particularly, a mounting S" bracket 212 is fixed to the support platform 204 and has spaced apart bosses 212a each of which have holes which are aligned so as to receive a bolt 213. The holes in the bosses 212 are also aligned with a vertically extending I 18 slot 227 provided in the upright side portion 203 of the base member 201. The shank 213a of the bolt 213 is received through the slot 227 and each of the holes 212b in the bosses 212a, and a nut and washer 215 are received over the end of the shank of the bolt 213 so as to locate the enlarged head 214 at a position spaced a predetermined distance from the in-side portion 205a which is sufficient to snugly receive the upright side portion 203 of the base member 201 therebetween.

The above described arrangement of the guide posts 207 and guide pin 211 accurately locate the support platform 204 relative to the base member 201 while allowing the support platform 204 to be pushed downwards from its uppermost position relative to the base member 201, and to cause the support platform 204 to return to the uppermost position. This arrangement is useful for accurately positioning the rail wheel detectors a30 (refer below) and, if the device 200 is struck by a train wheel, the impact will be absorbed without damage to the device 200.

.*.The mounting device 200 further comprises two pot magnets 223 mounted to an out-side of the upright side portion 203 of the base member 201, and which are positioned towards opposite ends of the elongate base member 201. Each pot magnet 223 has a rail contacting oo surface 228 which extends generally parallel to, and are spaced a predetermined distance from the upright side portion 203 which is sufficient to ensure that enlarged ::head 214 of the guide pin 211 does not contact the upright web 12 of the rail The mounting device 200 is also provided with a steel keeper flap 220 for each of the magnets 223. The keeper flaps 220 are pivotally mounted to respective aluminium connector parts 218 by hinges 217, and the connector parts 218 are in turn pivotally connected to the I I C-l I' i 19 respective ends of the upright side portion 203 of the base member 201 by hinges 219. The pivot axes of the hinges 217, 219 extend vertically so as to be generally parallel to the rail contacting surface 228 of the magnets 223. The connector part 218 causes the pivot axes of the hinges 217, 219 to be spaced apart a distance approximately the thickness of the magnets such that the keeper flaps 220 can lie flat against the rail contacting surfaces 228. Accordingly, the keeper flaps 220 can be moved between an in-use position against the rail contacting surfaces 228 of the magnets 223 so as to maintain the magnetic qualities of the pot magnets 223, and an out-of-use position (refer Figure 11) allowing the mounting device 200 to be mounted to a rail 10. The keeper flaps 220 preferably have a sheet of rubber material (not shown) affixed thereto which lies between the flap 22 and the magnet 223 when the flap 220 is in its in-use position. In this way, the flap 220 can be easily moved away from the in-use position and into the o out-of-use position.

In use, the device 200 is mounted to the upright *web 13 of the rail 10 by means of the magnets 223, and wherein the upper edge of the one side portion 205a of the support platform 204 will bear against the underside 13a of the overhang formed by the upper rail portion 13 of the rail 10 (refer Figure 13).

The mounting device 200 is also provided with a rail proximity sensor 229 which is mounted on the in-side portion 205a of the support platform 204 such that when the support platform 204 bears against the upper rail portion 13 of the rail 10, the one or more train wheel 0*t* proximity detectors 230 mounted to the support platform 204 will be in the optimum position for detecting the wheel of a train. Further, if the mounting device 200 becomes displaced so as to move the rail sensor 229 out of I I -I IIIW*~L lsllllYYll~r~-- contact with the rail 10, this would be detected by the status checking means of the system. Accordingly, when the central processing unit polls the status checking means, the fault will be detected and an alarm signal will be generated.

The train wheel proximity detectors 230 are designed such that the dynamic movement of the steel train wheel past the detector 230 will be recognised despite the constant presence of the steel rail 10. This is achieved by the detector 230 resetting itself if it detects a steel object in its vicinity for a period of 10 seconds or more. As such. after the detector 230 has been positioned adjacent to the steel rail for 10 seconds. the detector 230 will reset and thereafter will generally only detect a train wheel as it passes along the rail 10. Preferably, two detectors 230 are mounted on each support platform 204 of each device and are connected to the outpost units 135 in parallel in case one detector 230 fails.

Referring now to Figure 15. there is shown a display/control panel 133 which includes a key operated switch 132 for controlling, the mode of operation of the signalling system, and a schematic layout of the system which visually displays the information received from the signalling apparatus 120. and is specifically designed for a work-site encompassing two rail tracks which may be designated "near" and "far". More particularly, the visual display includes lights 105A and 106A which light up when the signalling apparatus 120 at posts 105 or 106 detect a train and an alarm mute i. button 134 for muting the audio alarm signal. Each of the "near" and "far" tracks shown on the panel also have a reset button 131. In this way. if a work train enters the control area 104 and is detected by post 105. and thereafter reverses back out from the control area 104, the operator will typically be o IIII ~bC~I -JI 21 aware of such movement of the work train and can reset the system.

Referring now to Figure 16, there is schematically shown the present system being used in a control area 104 which encompasses two rail tracks. At each of the posts 105 and 106, there is provided an outpost unit 235.

Each outpost unit 235 is connected to respective train wheel detectors 230 mounted to both the near and far rail tracks using mounting devices 200. Each outpost unit 235 is mounted on a tripod 238 and includes a battery box 236 containing batteries (not shown) for powering the outpost unit 235 and a cabinet 245 which houses a programmable state controller (not shown); a radio modem, radio, and radio antenna 237; a land line modem; and a fault indicator panel.

The master unit 239 is located in the vicinity of the work site 103, and includes the same features as each of the outpost units 235 and additionally is provided with display/control panel 233, a visual alarm signal in the form of a flashing light 240, and an audio alarm signal in 0 the form of a bell or horn 241.

The respective outpost units 235 and the master eoe unit 139 are in communication with each other by radio signals and/or by land lines 246. In use, if a radio link 25 is not available or is unreliable, the land lines 246 are .oo used.

The fault display panels on each of the outpost units 235 and the master unit 239 display whether there is .a fault with the rail detector 229, the wheel detector 230 of each of the near and far rail tracks, whether the battery power is low, whether the access door on the S. :cabinet of each of the outposts is open, whether the radio channel is busy (and therefore not reliable to use), and whether there is a communication links failure (ie in either in the radio link or the land line link). The 22 master unit 239 distinguishes between faults in the left outpost unit 235a and the right outpost unit 235b, and also has a tamper alarm which detects whether the outposts 235 have been tampered with. Typically, the fault indicator panels will be hidden behind the locked access door 245a of the cabinet 245, and need only be observed if the system detects a fault which may prejudice the safe operation of the system.

The left outpost unit 235a has external markings which are different to that of the right outpost unit 235b, and the display panel 233 of the master unit 239 schematically shows the different markings so that, when setting up the system, there is a minimal risk that the *units 235a and 235b will be mixed up which may cause the master unit 239 to display misleading information.

The audio alarm of the master unit 239 can generate two different alarm signals in order for the operator to .be able to distinguish between when a train is approaching and when a fault is detected in the system (ie thereby indicating an unreliable state).

.It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the 25 invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

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Claims (17)

1. A mounting device for use in positioning a wheel detector oin a rail which has a bottom flange, an upright web and anl upper rail portion, the mounting device including: attachment means for attaching the device against the upright web and between the bottom flange and an underside of the upper rail portion of the rail; a support platform to, in use, support one or more train wheel detectors, the support platform being mounted on the attachment means so as to be vertically movable thereon; and biasing means acting between the attachment means and the support platform to urge the support platform, in use, upwardly relative to the attachment means, the arrangement being such that upon the attachment means being 15 positioned onl the web of a rail the biasing means will urge the support means into contact with the underside of the tipper rail portion of the rail and thus position a train wheel detector onl the support platform in a predetermined relationship with the path of a train wheel passing along the rail.

2. A mounting device as claimed in claim 1, further including a location 20 checking means in the formn of one or more rail proximity sen,'Sors mounted :onl anl upper edge of the support platform, wherein, in use, the sensors are positioned inmmediately beneath the underside of the upper rail portion of the rail so as to detect whether the support platform is correctly positioned relative to the upper rail portion of the rail. 25

3. A mounting device as claimed in claim 1 or claim 2, in which the attachment means is in the form of a base member with one or more magnets mounted thereto so that the base member can be releasably secured to the rail.

4. A mounting device as claimed in claim 3, in which there are two magnets spaced apart along the length of the base member.

A mounting device as claimed in claim 3 or claim 4, in which tbe base member further includes cover means for the or each magnet, the cover means being inl the form of a magnetic flap movably mounted on the base member so as to be movable between an inl-use position covering the magnet and anl out-of-use position allowing the magnets to be positioned against the rail.

6. A mounting device as claimed in any one of claims 3 to 5, in which the base member is made from a non.-magnetic material.

7. A mounting device as claimed in claim 5. in which the or each flap is pivotally connected to a non-magnetic connector member which is in turn pivotally connected to the base, the pivot axes of the connections being generally parallel to a rail contact surface of the associated magnet so that the flap can be positioned flat against the contact surface of the respective magnet.

8. A mounting device as claimed in any one of claims 3 to 7, in which the support platform is in the form of a non-magnetic U-shaped channel, and the base member is in the form of an angle, with bottom portions of the support platform and the base mem-ber being positioned so as to face one another; wherein movement of the support platform relative to the attachment means is guided by at least one guide. at least one of the guides 15 being in the form of an upright guide post fixed to the bottom portion of either the base or the support platform and extending through a hole provided in the bottom portion of the other one of the base or support platform, the guide post having an end stop towards an outer end thereof which defines the uppermost position of the support platform; and wherein the biasing means is in the form of a helical spring which receives the guide post and extends between and bears against the bottom portions of the attach.,ni-it means and the support platform.

9. A mounting device as claimed in claim 8, in which there are three guides. two of which are in the form of the gi' de posts which are spaced apart along the device, with each guide post having an associated helical spring to bias the support platform upwardly relative to the attachment means; and wherein the third guide is in the form of a pin mounted to the support platform intermediate the guide posts, the pin extending laterally outwards to one side of the support platform and through a vertically extending slot in the upright portion of the base member. and wherein the pin I- as an enlarged head at its end which is spaced a predetermined distance away from the one side of the support platform sufficient to receive the upright side portion of the base mem-ber therebetween.

A train detection and signalling apparatus including: train wheel detection means for providing a detection signal when a wheel of a train is within a predetermined region; 3, a central processing unit, responsive to the detection signal and responsive to commands from anl operator, for providing a control signal; a train presence indicator, responsive to the control signal, for indicating whether the train is within a predetermined control area; and a mounting device for use in positioning the train wheel detector as claimed in any one of claims 1-9.

11. The apparatus of clafin 1.0 wherein the train wheel detection means detects the presence of the wheel magnetically, electrically, mechanically, or optically.

12. The apparatus of claim 11 wherein the train wheel detection means comprises a magnetic proximity detector mounted onl a rail along which the wheel of the train is to run.

13. The apparatus of claim 10 wherein the predetermined region can fit within a sphere having a radius of about tenl centimetres.

14. The apparatus of claim 10 wherein the train wheel detection means further comprises a status checking means, the central processing unit intermittently polls the status checking means to determine the status of the train wheel detectioni means, and the central processing unit generates anl alarni signal when the status checking means determines that a fault exists in the train wheel detection means.

The train detection and signalling apparatus of any one of claims to 14 ,in which there are at least two train wheel detection means spaced apart along a stretch of rail, the first detection means defining anl outer advance post and the second detection means defining anl outer departure post; the advance and departure posts delimiting the control area; and in which, in use, when a train wheel is detected at the advance post and is subsequently detected at the departure post, the control signal provided by the central processing unit will cause the train presence indicator to indicate that a train is within the control area until a detector signal is received from. the detection means at the departure post.

16. A method for detecting the presence of a train wheel onl a rail having a bottom flange, an upright web and anl upper rail portion, the method comprising the steps of attaching to the rail a mounting device as claimed in any one of claims 1 to 9 on the support platform. of which is supported at least one train wheel detector adapted to produce a detection signal when a train wheel is within a 1 >r of" predetermined distance of the detector, the attachment means of the mounting device being releasably attached to the web of the rail with the support means being urged into contact with the underside of the upper rail portion of the rail by the biasing means, and monitoring the one or more train wheel detectors for the production of a detection signal.

17. A mounting device for use in positioning a wheel detector on a rail substantially as hereinbefore described with reference to Figs 10 to 13. Dated this 9th day of March 1997. JOHN MALDEN ELLIOTT AND BRADLEY DAMIEN DONOVAN Patent Attorneys for the Applicant: F.B. RICE CO. o o *o *oo *oo *ee *i *oooo ABSTRACT A railway work-site warning system which includes one or more train wheel detectors at predetermined positions along a stretch of rail, the or each train wheel detector providing a detection signal to a central processing unit when a train wheel is detected within a predetermined region surrounding the or each detector. The central processing unit responds to the detection signal by providing a control signal to a train presence indicator which indicates whether a train is within a predetermined control area. The operator can also operate the central processing unit to provide a control signal which cancels an indication from the train presence indicator that a train is in the control area. Preferably, the apparatus comprises at least two train wheel detectors spaced apart along a stretch of rail so as to delimit the control area, and wherein a first one of the train wheel detectors defines an outer advance post which provides a detection signal to the central processing unit, which in turn provides a control signal to the train presence indicator to indicate the presence of a train in the control area, and the second one of the train wheel detectors defines an outer departure post which provides a detection signal to the central processing unit, which in turn provides a control signal to the train presence indicator to cancel the indication that a train is in the control area. S. Preferably, the or each train wheel detector comprises a magnetic proximity detector mounted to a rail along which the wheel of the train is to run. There is also provided a mounting device for use in positioning a train wheel detector proximate to a rail and includes an attachment arrangement to locate the device in a predetermined position relative to the rail, a support platform for supporting one or more train wheel detectors, and being mounted on the attachment arrangement so as to be vertically movable away from an uppermost position, and a spring bias acting between the attachment arrangement 0d the support platform to urge the support platform towards the uppermost position. Preferably, the attachment arrangement includes a base member having one or more magnets mounted thereto so that the base member can be releasably secured against an outside of an upright web of the rail. The mounting device may also include a movable cover for the or each magnet, the cover being movable between an in-use position covering the magnet and an out of use position allowing the device to be positioned against the rail. Preferably, the movement of the support platform relative to the base member is guided by at least one guide in the form of a guide post mounted to the base member and extending through a hole in the support platform, the guide post having an end stop towards its outer end, and wherein a spring bias is provided by a helical spring which receives the guide post and is between and bears against each of the base member and the support platform.