Redundancy switching of detection points

Abstract

A method for operating an axle counter system for monitoring the occupation status of a track section being limited by counting positions which have at least one detection point and at least one counting position a set of redundant detection points, includes the steps of: (a) incrementing or decrementing axle counter values in dependence of the moving direction of a passing axle; (b) transmitting the axle counter value to an axle counter evaluator; (c) determining the number of remaining axles within the track section; and (d) outputting a track occupation status. Prior to step (c) for each counting position exactly one detection point is selected for further processing independent of the selection at any other counting position. In step (c) the counter values of the selected detection points are used for determining the number of remaining axles and the counter values of the non-selected redundant detection points are ignored.

Claims

1. A method for operating an axle counter system for monitoring the occupation status of a given track section, the track section being limited by counting positions, wherein at least one counting-in-position and a basic counting-out-position is provided, wherein at each counting position at least one detection point is provided and at least one counting position an additional detection point is provided, the basic and the additional detection point forming a set of redundant detection points, wherein each of the basic and additional detection points are a double sensor, said method comprising the steps of: (a) incrementing or decrementing axle counter values by means of the detection points in dependence of the moving direction of a passing axle; (b) transmitting the axle counter value of each detection point to an axle counter evaluator; (c) selecting for each counting position exactly one basic or additional detection point for further processing independent of the selection at any other counting position, wherein the axle counter values of the of the selected basic or additional detection points are used for determining the number remaining axles within the track section and that the counter values of the non-selected detection basic or additional points of the at least one set of redundant detection points are ignored; (d) determining the number of remaining axles within the track section by means of the axle counter evaluator by comparing the axle counter values of the selected basic or additional detection points at the counting-in-positions with those at the counting-out-positions; and (e) outputting a track occupation status report in dependence of the number of remaining axles within the track section.

2. The method according to claim 1, wherein a quality value is determined and the selection of the basic or additional detection points is carried out in dependence of a quality value.

3. The method according to claim 2, wherein in case of an error an error message is transmitted by the erroneous detection point to the axle counter evaluator, wherein a quality factor is assigned to each error message in dependence of the relevancy of the error, and that the quality value for each detection point is determined by adding the quality factors of the transmitted error messages of the respective detection point.

4. The method according to claim 3, wherein the error messages are at least one of: defect warning with quality factor QF1, wheel pulse without counting with quality factor QF2, drift warning with quality factor QF3 and long wheel pulse with quality factor QF4.

5. The method according to claim 4, wherein the following applies: QF1QF2QF3QF4.

6. The method according to claim 5, wherein the quality factors of the error messages comply with: QF1>QF2>QF3>QF4.

7. The method according to claim 5, wherein the quality factors of the error messages comply with: QF1:QF2:QF3:QF4=8:3:2:1.

8. The method according to claim 1, wherein for each set of redundant detection points the difference between the counter values of the basic and additional detection points of a set of redundant detection points is determined, and that the selection of the basic or additional detection points is carried out in dependence of the determined difference between the counter values, wherein the basic or additional detection point having the higher counter value is selected, in case that the difference of the counter values exceeds a predefined threshold.

9. The method according to claim 2, wherein for each set of redundant detection points the difference between the counter values of the basic and additional detection points of a set of redundant detection points is determined, and that the selection of the basic or additional detection points is carried out in dependence of the determined difference between the counter values, wherein the basic or additional detection point having the higher counter value is selected, in case that the difference of the counter values exceeds a predefined threshold, wherein in case that the difference does not exceed the predefined threshold the selection of the detection points is carried out in dependence of the quality value.

10. The method according to claim 1, wherein the selection of the basic or additional detection points and the calculation of the number of remaining axles in the section is performed by a common axle counter evaluator.

11. An axle counter system for performing the method according to claim 1, the axle counter system comprising detection points installed at counting positions along a track, wherein at each counting position a basic detection point is provided, and wherein at least one counting position an additional detection point is provided, the basic and the additional detection point forming a set of redundant detection points, wherein each of the basic and the additional detection points is a double sensor, wherein all detection points are connected to one common axle counter evaluator, the axle counter evaluator being equipped for selecting the basic or additional detection points and determining the number of remaining axles within the track section.

12. The axle counter system according to claim 11, wherein the axle counter evaluator is provided with means for determining a quality value.

13. The axle counter system according to claim 12, wherein the axle counter evaluator comprises at least two independent data processors.

14. The axle counter system according to claim 13, wherein the basic and additional detection points of a set of redundant detection points are installed at the same side of the track being spaced apart from each other.

15. The axle counter system according to claim 14, wherein the basic and additional detection points of a set of redundant detection points are installed at the opposite sides of the track.

16. The axle counter system according to claim 11, wherein the axle counter evaluator comprises at least two independent data processors.

17. The axle counter system according to claim 11, wherein the basic and additional detection points of a set of redundant detection points are installed at the same side of the track being spaced apart from each other.

18. The axle counter system according to claim 11, wherein the basic and additional detection points of a set of redundant detection points are installed at the opposite sides of the track.

19. A method for operating an axle counter system for monitoring the occupation status of a given track section, the track section being limited by counting positions, wherein at least one counting-in-position and at least one counting-out-position is provided, wherein at each counting position a basic detection point is provided and at least one counting position an additional detection point is provided, the basic and the additional detection points forming a set of redundant detection points, wherein each of the basic and additional detection points are a double sensor, said method comprising the steps of: incrementing or decrementing axle counter values by means of the detection points in dependence of the moving direction of a passing axle; transmitting the axle counter value of each detection point to an axle counter evaluator; selecting exactly the basic or additional detection point for each counting position for further processing independent of the selection at any other counting position; determining the number of remaining axles within the track section by means of the axle counter evaluator by comparing the axle counter values of the selected basic or additional detection points at the counting-in-positions with those at the counting-out-positions, wherein the counter values of the selected basic or additional detection points are used for determining the number of remaining axles within the track section and that the counter values of the non-selected basic or additional detection points are ignored; and outputting a track occupation status report in dependence of the number of remaining axles within the track section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is shown in the drawings and will be explained in detail using exemplary embodiments.

(2) FIG. 1 shows a schematic drawing of an axle counter system according to the state of the art;

(3) FIG. 2 shows a schematic drawing of an error tolerant axle counter system according to the state of the art;

(4) FIG. 3 shows a schematic drawing of the axle counter system of FIG. 2 in case of an error;

(5) FIG. 4 shows a schematic drawing of an embodiment of the inventive axle counter system and method;

(6) FIG. 5 shows a schematic drawing of another embodiment of the inventive axle counter system and method with the detection points being arranged on the same side of the track;

(7) FIG. 6 shows a schematic drawing of further embodiment of the inventive axle counter system and method with determination of the quality factor;

(8) FIG. 7 shows a schematic drawing of an alternative embodiment to the embodiment of the inventive axle counter system and method with determination of the axle counter difference;

(9) FIG. 8 shows a schematic drawing of an axle counter evaluator according to an embodiment of the inventive axle counter system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) FIG. 1 shows a schematic drawing of a common axle counter system AC1 according to the state of the art. For a train moving from left to right the first counting position CP1 serves as counting-in position into the first track section TS1, the counting position CP3 serves as counting-out position. Counting position CP2 is counting-out position out of track section TS1 and counting-in position to track section TS2. Detection points DP1, DP2, DP3 are positioned along the track. The counting positions CP1, CP2, CP3 are provided with additional detection points DP1, DP2, DP3

(11) The signal of the detection points DP1, DP2, DP3 is registered by a connected first axle counter evaluator ACE1. The signals of the additional detection points DP1, DP2, DP3 are registered by a connected second axle counter evaluator ACE1. Both axle counter evaluators ACE1, ACE1 are determining an occupation status F, O and report their determined occupation status F, O to an associated interlock IL. The status can report the track to be free F or occupied O. Sometimes, however, a detection point DP1, DP2, DP3, DP1, DP2, DP3 is defective and an occupation status cannot be determined correctly. In this case the axle counter evaluator ACE1, ACE1 reports the track to be occupied O or it reports a defect D. At the interlock it is decided which occupation status F, O the track section TS1 is given. For safety reasons the status will be set to occupied O if the track status is unclear or cannot be determined.

(12) FIG. 2 shows a schematic drawing of another axle counter system AC2 known from the state of the art. All detection points DP1, RDP1, DP2, DP1, DP2, DP3 report to an axle counter evaluator ACE2. The axle counter evaluator ACE2 is determining the number of remaining axles for every combination of detection points DP1, DP2, DP3, DP1, DP2, DP3.

(13) This means: #DP1+#DP2+#DP3 #DP1+#DP2+#DP3 #DP1+#DP2+#DP3 #DP1+#DP2+#DP3 #DP1+#DP2+#DP3 #DP1+#DP2+#DP3 #DP1+#DP2+#DP3 #DP1+#DP2+#DP3
with # being the axle counter value of the particular detection point DP1, DP2, DP3, DP1, DP2, DP3.

(14) Ideally the 8 sums will be equal. The problem with this solution is which sum is to be trusted if the sums are not equal. The state of the art introduces decision routines to ensure a safe operation. In doubt, the track section will be reported occupied.

(15) FIG. 3 shows a schematic drawing of the same axle counter system AC2 as FIG. 2 with an obvious error in one of the detection points, (here additional detection point DP2). In this case all sums resulting from the axle counter values of the erroneous detection point DP2 are excluded from the decision, which would leave four sums for the determination of the occupation status for the given example.

(16) FIG. 4 shows a schematic drawing of an embodiment of an inventive axle counter system AC3. The axle counter system AC3 comprising counting positions CP1, CP2, CP3 along a track section TS1. In FIG. 4 at each counting position CP1, CP2, CP3 a set of redundant detection points is provided, each set comprising a basic detection point DP1, DP2, DP3 and a redundant detection point RDP1, RDP2, RDP3. Yet it should be mentioned that the inventive method also works if some counting positions are provided with only one detection point. In FIG. 4 the counting positions CP3 and CP2 are treated as counting-out positions; counting position CP1 is treated as counting-in position for track section TS1. According to the invention all detection points DP1, DP2, DP3, RDP1, RDP2, RDP3 are connected to one common axle counter evaluator ACE 3. For each counting position CP1, CP2, CP3 the axle counter evaluator ACE3 selects one detection point (either the basic detection point DP1, DP2, DP3 or the related redundant detection point RDP1, RDP2, RDP3). The selections are carried out independently from each other, i.e. for each counting position CP1, CP2, CP3 one detection point is selected which is taken into account for the further processing, independently of the selection result at any other counting position. Thereby the best working detection point DP1, DP2, DP3, RDP1, RDP2, RDP3 can be selected for each counting position CP1, CP2, CP3.

(17) The axle counter values # of the selected detection points DP1, DP2, DP3, RDP1, RDP2, RDP3 (and only those of the selected detection points) are then used to determine the number of remaining axles within the track section TS1 by subtracting the axle counter values of the selected detection points RDP2, DP3 of all counting-out positions (here: CP2, CP3) from the axle counter value of the selected detection point DP1 of all counting in positions (here: CP1). For the example given in FIG. 4 the number of remaining axles would be: #DP1(#RDP2+#DP3). In case another counting-in position DPX would exist, e.g. at a crossing (not shown in FIG. 4) the number of remaining axles would be: (#DP1+#DPX)(#RDP2+#DP3). For trains moving in opposite direction, CP2 and CP3 are treated as counting-in positions and, to stick with the given example of FIG. 4, RDP2 and DP3 would be the selected detection points of the counting-in positions. Thus, the number of remaining axles would be: (#RDP2+#DP3)#DP1.

(18) If the calculated number of remaining axles is 0, the track section TS1 is considered to be free and the occupation status free F is transmitted to the interlock IL. Otherwise the occupation status occupied O is transmitted to the interlock IL.

(19) In order to prevent the two sensors of a detection point DP1, DP2, DP3, RDP1, RDP2, RDP3 of influencing each other, the two sensors usually work on different frequencies. An often used setting is 28 kHz for one and 30 kHz for the other sensor. In order to prevent the sensors of the basic detection points DP1, DP2, DP3 to influence the sensors of the related redundant detection points RDP1, RDP2, RDP3 operating on the same frequency, the detection points of a counting position are positioned at a distance of approximately 2 m.

(20) In FIG. 4 the basic detection points DP1, DP2, DP3 and the related redundant detection points RDP1, RDP2, RDP3 are therefore mounted on opposite sides of the track (at different rails of the track), with a small lateral offset. The lateral offset is not mandatory but can ensure an adequate distance between the DP1, DP2, DP3 and related redundant detection points RDP1, RDP2, RDP3.

(21) FIG. 5 shows a schematic drawing of another embodiment of the inventive axle counter system AC4, wherein the basic detection points DP1, DP2, DP3 as well as the redundant detection points RDP1, RDP2, RDP3 of the axle counter system AC4 are mounted on the same side of the track (at the same rail) with a lateral offset between the basic detection point DP1, DP2, DP3 and its related redundant detection point RDP1, RDP2, RDP3. The selection of the detection points and the evaluation of the number of remaining axles are carried out as described above.

(22) In both cases the lateral offset has to be chosen small enough (preferably <3 m) to prevent a train or a part of a train (e.g. a complete lost wagon) standing in between the basic detection point and its related redundant detection point without being registered properly.

(23) FIG. 6 shows a schematic drawing of another embodiment of the inventive axle counter system AC5, wherein the selection of the detection points is carried out on the basis of quality values.

(24) Each detection point DP1, DP2, DP3 and each redundant detection point RDP1, RDP2, RDP3 generate counter values # by counting passing axles. The counter values # of each detection point DP1, DP2, DP3, RDP1, RDP2, RDP3 are transmitted to the axle counter evaluator ACE4. Preferably the transmission of the axle counter values is carried out cyclically. Additionally, in case of an error, the detection points DP1, DP2, DP3, RDP1, RDP2, RDP3 in question report error messages E to the axle counter evaluator.

(25) Every kind of error message is assigned a previously set quality factor i(E), j(E). The axle counter evaluator ACE4 adds the quality factors i(E), j(E) for each detection point DP1, DP2, DP3, RDP1, RDP2, RDP3 over a predetermined time, usually 30 s, in order to determine the quality value.Math.i, .Math.j for every detection point DP1, DP2, DP3, RDP1, RDP2, RDP3.

(26) The quality factors i(E), j(E) may be different for different kind of error messages, for example more safety-relevant error messages may be assigned a higher quality factor i(E), j(E) than less relevant error messages.

(27) For counting position CP1, CP2 the detection point with the lowest quality value.Math.i, .Math.j is selected (here: DP1, RDP2). At counting position CP3 for both, the basic detection point DP3 and the redundant detection point RDP3, the same quality value has been determined. In this case any of the detection points DP3, RDP3 can be selected (here: DP3).

(28) The axle counter values # of each of the selected detection points DP1, RDP2, DP3 are used to determine the number of remaining axles in the track section TS1. According to the determined number of remaining axles the track section TS1 an occupation status free F or occupied O is reported to the interlock IL.

(29) Additionally the error messages E of each detection point DP1, DP2, DP3, RDP1, RDP2, RDP3 are reported to the interlock IL, so that accordingly a reset of the corresponding detection points DP1, DP2, DP3, RDP1, RDP2, RDP3 may be initiated or a service can be scheduled if necessary.

(30) FIG. 7 shows a schematic drawing of yet another embodiment of the inventive axle counter system AC6. In this embodiment the selection of the detection points DP1, DP2, DP3, RDP1, RDP2, RDP3 is carried out on the basis of the difference # of the axle counter values # of the basic detection point DP1, DP2, D3 and the related redundant detection point RDP1, RDP2, RDP3 of a counting position CP1, CP2, CP3. The axle counter value # of each basic detection point DP1, DP2, DP3 is compared to the axle counter value # of its related redundant detection point RDP1, RDP2, RDP3. If the absolute value of the difference of the axle counter values # is greater than a predefined threshold Th the detection point DP1, DP2, DP3, RDP1, RDP2, RDP3 with the higher axle counter value # is selected. In the example depicted in FIG. 7, for counting position CP2 the axle counting value # of redundant detection point RDP2 is significantly greater than the axle counting value # of detection point DP2 and the absolute value of the difference of the axle counter values # exceeds the threshold Th. Accordingly redundant detection point RDP2 is selected for counting position CP2.

(31) For counting position CP3 the difference # of axle counter values # of basic detection point DP3 and the related redundant detection point RDP3 is smaller than threshold Th. For counting position CP1 the axle counter values # of detection point DP1 and the related redundant detection point RDP1 are equal. In both cases the selection of the detection points can be carried out on the basis of a quality value as depicted in FIG. 6 and described above.

(32) Again, the axle counter values of the selected detection points DP1, RDP2, DP3 is used to determine the number of remaining axles in the track section TS1. Accordingly, the occupation status F, O is reported to the related interlock IL.

(33) This mechanism detects blind detection points.

(34) FIG. 8 shows a schematic drawing of an axle counter evaluator ACE6 comprising three independent data processors P1, P2, P3. Each of the three processors carries out the same actions as described above, separately, so that a high safety and redundancy level is reached. For the embodiments of the inventive axle counter system shown in FIGS. 4 to 7 the axle counter evaluator ACE6 can be used instead of axle counter evaluator ACE3, ACE4, ACE5 respectively.

(35) The inventive method carries out a selection of one detection point for each counting position. The choice which detection point will be selected depends on the status and the history of the both detection points of a set of redundant detection points: Initially, one of the two detection points will be taken if both detection points seem to be ok. If one detection point has a defect, the other one will be taken. A defect can be determined by comparing the counter values of the detection points of a counting position and/or by comparing a quality value based on error messages weighted with quality factors.

LIST OF REFERENCE SIGNS

(36) AC Axle counter system ACE Axle counter evaluator CP Counting position DP Basic detection point DP Additional detection point RDP Redundant detection point TS Track section IL Interlock F Occupation status: free O Occupation status: occupied D defect E Error messages of the listed detection points i(E), j(E) Quality factor of error E i(E), Quality value j(E) # Axle counter value # Difference of axle counter value between basic detection point and the related redundant detection point Th Threshold P Data processor