CA1288853C - Arrangement for monitoring a track section - Google Patents
Arrangement for monitoring a track sectionInfo
- Publication number
- CA1288853C CA1288853C CA000547559A CA547559A CA1288853C CA 1288853 C CA1288853 C CA 1288853C CA 000547559 A CA000547559 A CA 000547559A CA 547559 A CA547559 A CA 547559A CA 1288853 C CA1288853 C CA 1288853C
- Authority
- CA
- Canada
- Prior art keywords
- track section
- arrangement
- track
- criterion
- voltage source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L1/00—Devices along the route controlled by interaction with the vehicle or vehicle train, e.g. pedals
- B61L1/18—Railway track circuits
- B61L1/181—Details
- B61L1/185—Use of direct current
Abstract
Abstract Arrangement for Monitoring a Track Section An arrangement is disclosed for monitoring an at least single-rail insulated track section for its unoccupied/
occupied condition and for any rail breakage. The track section (GA) is designed as a DC track circuit. At one end of the track circuit, a switching device (SCH) periodically interconnects the two rails (S1, S2), thus modulating the track current, At the other end, a DC voltage source (SP) and an evaluation circuit (RM, MV, C, R, SW, MK) are connected to the rails (S1, S2).
The evaluation circuit evaluates the current supplied by the DC voltage source (SP) with respect to the magnitude of its changes and derives therefrom a criterion for the condition of the track section (GA).
(Figure)
occupied condition and for any rail breakage. The track section (GA) is designed as a DC track circuit. At one end of the track circuit, a switching device (SCH) periodically interconnects the two rails (S1, S2), thus modulating the track current, At the other end, a DC voltage source (SP) and an evaluation circuit (RM, MV, C, R, SW, MK) are connected to the rails (S1, S2).
The evaluation circuit evaluates the current supplied by the DC voltage source (SP) with respect to the magnitude of its changes and derives therefrom a criterion for the condition of the track section (GA).
(Figure)
Description
8~i3 The present invention relates to an arrangement for monitoring an at least single-rail insulated ~rack section using a track circuit fed at one end from a DC voltage source.
The technical problem to be solved by such an arrangement is to monitor the condition of a ~rack section, par~icularly for occupancy detection or broken-rail detection.
To solve this problem, various track-circuit arrangementæ are known. In all these arrangements r a track voltage is applied to ~he two rails at one end of a track section, and the track voltage appearing at the other end of the track section i5 measured, with a condition criterion for the respective track section being derived ~rom the amplitude of the measured track voltage. If there are vehicles in the track section, the measured voltage will lie below the threshold value and the section will be indicated as occupied; if the track section is unoccupied, the measured voltage will lle above the threshold value. If a rail breakage occurs wlthin the ~rack section, the measured voltage value will lie below the threshold value, too, and the track section will be indicated as occupied.
Further means for monitoring the unoccupied/occupied condition o~ a tracX section are axle counters, which count the axles e~ntering and leaving the track section to be monitored, thereby determining the number of axles present in the track section. If this number 1~s æero, the track section will be indicated as unoccupied.
Conventional track c1rcuits have the dl~advantage that, due to the widely varying ballast resistance of the track, their possible ef~ective length is relatively short. To monitor a long .
~S3 2 620~6-lg6 line, a correspondingly great number of track circuits with jusk as many feed-in points and evaluation units are necessary. With axle-counter arrangements, even long track sections can be monitored. However, such arrangements are disadvantageous in that they do not detect any broken rails, and that at least one communication line is required between the axle counters at the beginning and the end of each track section and a common evaluation unit.
The arrangement for monitoring an at léast sinyle-rail insulated track section according to the invention is characterized in that at the other end of the track section there is a s~itching device which electrically interconnects the two rails of the track section at regular time intervals, and that, to derlve and output a criterion for the condition of the track section, an evaluation circuit evaluates the amplitude of the AC
component flowing through the DC vol~age source by comparing it with a thrashold value.
;, . ~' ' , ~ ',, ' ~2~3 One of the advantages of the arrangement according to the invention over conventional track circuits lies in the fact that a considerably longer track section can be monitored, with the required amount of circuitry being extremely small compared to conventional track circuits and considering the great effective length achieved.
Furthermore, no additional electrical interconnections, such as the communication line required with axle counters, are necessary between the two ends of the track section and a common evaluation unit. Because of these advantages, the arrangement according to the invention can be easily used as a complement to existing axle-counter ~arrangements if additional broken-ra;l protection is desired. This combination is appropriate on little used lines since occupancy detection ;by means of a track circuit is not possible there because of rust formation on the rails and the resulting high contact resistances between the wheels of the vehicles and the rails.
An embod;ment of an arrangement according to the invention will now be explained with reference to the accompany;ng drawing.
Both rails S1, S2 of the track section to be monitored, G~, are electrically separated from the rails of the adjoining track sections by insulated rail joints ISo In the case of electrified lines, only single-ra;l insulation is possible because one rail is used for the traction return current.
~ H.Uebel-H.Fricke 52-13 :
.. . .
. ~
.: . . .
~2~
Located at one end of the track section GA is a DC
voltage source SP, which feeds its voltage through a measuring res;stor RM into the ra;ls S1, S2 of the track sect;on GA. The voltage drop across the measuring res;stor RM passes to an evaluation circu;t consisting of a measuring amplifier MV, a differentiator formed by a capac;tor C and a res;stor R, a threshold,switch SW, and a retr;ggerable monostable muLtivibrator MK. At the other end of the track sect;on GA, a clock generator TG
controls a relay RL. The two ra;ls S1, S2 of the track are interconnected there by a sw;tch;ng contact SCH of the relay RL.
The current supplied by the DC voltage source SP varies between two values depend;ng on the position of the switching contact SCHo If the track section GA is unoccupied, in which case the switching contact SCH
is open, current flows only through the ballast re-sistance of the track. When the switching contac~ SCH
is closed, a cons;derably greater port;on of the current flows through the sw;tching contact SCH~ The direct current thus varies between two values whose difference can be determined.
If there are vehicles ;n the track sect;on GA~ the two rails S1, S2 are electrically interconnected by the axles of the vehicles. The position of the switch;ng contact SCH then has only a minimum effect on the current supplied by the DC voltage source, so that the difference between the two current ualues becomes very smaLl. If a rail breakage occurs within the track H~Uebel-H.Fr;cke 52-13 .' . . :' . , ~, , , -.
- : . . .. .
sect;on, the difference between the current values be-comes very small, too, because the port-ion of current passing through the closed sw;tching contact SCH can pass the break only via the ballast. By evaluating the magnitudes of the current-value differences, a criterion for the condition of the track section GA can thus be derived for occupancy detection and broken-~all de-tection.
The current delivered by the DC voltage source SP
causes a voltage drop across the measuring resistor RM
which is coupled out with the aid of the measuring amplifier MV~ The changes in current caused by the switch SCH thus result in corresponding voltage changes at the output of the measuring ampl;fier MV. The out-put of the measuring amplifier MV ;s coupled to the input of the threshold switch SW through the dif-ferentiator consisting of the capac;tor C and the re-sistor R. Each voltage step at the output of the measuring amplifîer MV thus causes a positive or nega-tive needle~shaped voltage pulse across the resistor R and, hence, at the input of the threshold switch SW, If the amplitude of the needle pulse exceeds a pre-determined threshold, the output of the threshold switch SW changes its state for the time during whish th,e amplitude is exceeded.
The output signals of the ~hreshold switch SW are applied to the clock input of the retriggerable mono- ¦
stable multivibrator MK. This clock input is a dynamic input. In the stable st~ate of the monostable multi-vibrator MK~ the output MA of the latter is at a high H Uebel-H~Fricke 52-13 ~2~ i3 level. The monostable multiv;hrator is tr;ggered by a negative voltage step at ;ts clock ;nput. Accord;ngly, ;ts output MA goes to a low level after each negat;ve volt3ge step. It rema;ns ;n th;s state for a pre-determ;ned t;me ;nterval. Then, the monostable mult;-vibrator MK returns to ;ts stable state unless a new negat;ve voltage step occurred at ;ts ;nput.before the end of said predetermined time ;nterval.
The DC voltage source SP and the measuring res;stor RM
should be Chosen so that, ~ith the switching contact SCH closed, a voltage of about 1 V appears at the feed-in point of the track sect;on. The clock generator TG
preferably operates at a frequency ;n the range from 0 1 Hz to 10 H~, so that the capacitances and induc-tances of the track can be neglected~ The dwell time of the monostable mult;v;brator MK must be longer than the period of the clock generator TG.
In the normal case, when no rails are broken and the track section GA is unoccupied, large current-value differences occur in the measuring resistor RM in the rhythm of the operation of the switch SCH. These large differences cause the monostable multivibrator MK to be continuously retr;ggered, so that its output MA is constantly at a,low level, the criterion for the unoccupied con-d;t;on of the track section. If a ra;l breakage occurs, or the track section GA is occupied by vehicles, the current-value differences ;n the measuring res;stor RM
wtll become so small that the threshold switch SW no longer changes its state As a result, the monostable multivibrator MK is no longer retriggered and, 9t the H.Uebel-H.Fricke 52-13 . . ' .
'. ' ' ''' , ' , : ' ''" . '' " ,;' ': ' '' .. , ~28~3 end of its dwell time, returns to the stable state~
so that the output MA goes high, thereby indicating a rail breakage or the occupied condition of the track section.
The arrangement according to the invention can be used to advantage as a complement to existing ax.~e counter circuits for indi~cating Long track sections'as un-occupied or occupied if additional broken-rail protec-tion is to be provided and occupancy detection by means of the arrangement according to the invention is not possible, e.g., because the raiLs of the track section are subject to heavy rusting~ This ;s frequently the case on li~tle used lines. If the arrangement according to the invention is combined with an axle-counter arrangement, the output signals of the two arrangements may act on~a common output ~hich also provides an "occupied" ;ndication when a rail has broken within the track section.
To eliminate any disturbances in the time funct;on of the curr~nt~ a correlator may be connected between the measuring amplifier and the differentiator to form an autocorrelation of the time function of the current flowing through the DC voltage source. This, however, requires that the clock generator TG should operate with high precision~ In that case, a crystal-controlled clock generator should be used.
H.Uebel-H,Fricke 52-13 .
The technical problem to be solved by such an arrangement is to monitor the condition of a ~rack section, par~icularly for occupancy detection or broken-rail detection.
To solve this problem, various track-circuit arrangementæ are known. In all these arrangements r a track voltage is applied to ~he two rails at one end of a track section, and the track voltage appearing at the other end of the track section i5 measured, with a condition criterion for the respective track section being derived ~rom the amplitude of the measured track voltage. If there are vehicles in the track section, the measured voltage will lie below the threshold value and the section will be indicated as occupied; if the track section is unoccupied, the measured voltage will lle above the threshold value. If a rail breakage occurs wlthin the ~rack section, the measured voltage value will lie below the threshold value, too, and the track section will be indicated as occupied.
Further means for monitoring the unoccupied/occupied condition o~ a tracX section are axle counters, which count the axles e~ntering and leaving the track section to be monitored, thereby determining the number of axles present in the track section. If this number 1~s æero, the track section will be indicated as unoccupied.
Conventional track c1rcuits have the dl~advantage that, due to the widely varying ballast resistance of the track, their possible ef~ective length is relatively short. To monitor a long .
~S3 2 620~6-lg6 line, a correspondingly great number of track circuits with jusk as many feed-in points and evaluation units are necessary. With axle-counter arrangements, even long track sections can be monitored. However, such arrangements are disadvantageous in that they do not detect any broken rails, and that at least one communication line is required between the axle counters at the beginning and the end of each track section and a common evaluation unit.
The arrangement for monitoring an at léast sinyle-rail insulated track section according to the invention is characterized in that at the other end of the track section there is a s~itching device which electrically interconnects the two rails of the track section at regular time intervals, and that, to derlve and output a criterion for the condition of the track section, an evaluation circuit evaluates the amplitude of the AC
component flowing through the DC vol~age source by comparing it with a thrashold value.
;, . ~' ' , ~ ',, ' ~2~3 One of the advantages of the arrangement according to the invention over conventional track circuits lies in the fact that a considerably longer track section can be monitored, with the required amount of circuitry being extremely small compared to conventional track circuits and considering the great effective length achieved.
Furthermore, no additional electrical interconnections, such as the communication line required with axle counters, are necessary between the two ends of the track section and a common evaluation unit. Because of these advantages, the arrangement according to the invention can be easily used as a complement to existing axle-counter ~arrangements if additional broken-ra;l protection is desired. This combination is appropriate on little used lines since occupancy detection ;by means of a track circuit is not possible there because of rust formation on the rails and the resulting high contact resistances between the wheels of the vehicles and the rails.
An embod;ment of an arrangement according to the invention will now be explained with reference to the accompany;ng drawing.
Both rails S1, S2 of the track section to be monitored, G~, are electrically separated from the rails of the adjoining track sections by insulated rail joints ISo In the case of electrified lines, only single-ra;l insulation is possible because one rail is used for the traction return current.
~ H.Uebel-H.Fricke 52-13 :
.. . .
. ~
.: . . .
~2~
Located at one end of the track section GA is a DC
voltage source SP, which feeds its voltage through a measuring res;stor RM into the ra;ls S1, S2 of the track sect;on GA. The voltage drop across the measuring res;stor RM passes to an evaluation circu;t consisting of a measuring amplifier MV, a differentiator formed by a capac;tor C and a res;stor R, a threshold,switch SW, and a retr;ggerable monostable muLtivibrator MK. At the other end of the track sect;on GA, a clock generator TG
controls a relay RL. The two ra;ls S1, S2 of the track are interconnected there by a sw;tch;ng contact SCH of the relay RL.
The current supplied by the DC voltage source SP varies between two values depend;ng on the position of the switching contact SCHo If the track section GA is unoccupied, in which case the switching contact SCH
is open, current flows only through the ballast re-sistance of the track. When the switching contac~ SCH
is closed, a cons;derably greater port;on of the current flows through the sw;tching contact SCH~ The direct current thus varies between two values whose difference can be determined.
If there are vehicles ;n the track sect;on GA~ the two rails S1, S2 are electrically interconnected by the axles of the vehicles. The position of the switch;ng contact SCH then has only a minimum effect on the current supplied by the DC voltage source, so that the difference between the two current ualues becomes very smaLl. If a rail breakage occurs within the track H~Uebel-H.Fr;cke 52-13 .' . . :' . , ~, , , -.
- : . . .. .
sect;on, the difference between the current values be-comes very small, too, because the port-ion of current passing through the closed sw;tching contact SCH can pass the break only via the ballast. By evaluating the magnitudes of the current-value differences, a criterion for the condition of the track section GA can thus be derived for occupancy detection and broken-~all de-tection.
The current delivered by the DC voltage source SP
causes a voltage drop across the measuring resistor RM
which is coupled out with the aid of the measuring amplifier MV~ The changes in current caused by the switch SCH thus result in corresponding voltage changes at the output of the measuring ampl;fier MV. The out-put of the measuring amplifier MV ;s coupled to the input of the threshold switch SW through the dif-ferentiator consisting of the capac;tor C and the re-sistor R. Each voltage step at the output of the measuring amplifîer MV thus causes a positive or nega-tive needle~shaped voltage pulse across the resistor R and, hence, at the input of the threshold switch SW, If the amplitude of the needle pulse exceeds a pre-determined threshold, the output of the threshold switch SW changes its state for the time during whish th,e amplitude is exceeded.
The output signals of the ~hreshold switch SW are applied to the clock input of the retriggerable mono- ¦
stable multivibrator MK. This clock input is a dynamic input. In the stable st~ate of the monostable multi-vibrator MK~ the output MA of the latter is at a high H Uebel-H~Fricke 52-13 ~2~ i3 level. The monostable multiv;hrator is tr;ggered by a negative voltage step at ;ts clock ;nput. Accord;ngly, ;ts output MA goes to a low level after each negat;ve volt3ge step. It rema;ns ;n th;s state for a pre-determ;ned t;me ;nterval. Then, the monostable mult;-vibrator MK returns to ;ts stable state unless a new negat;ve voltage step occurred at ;ts ;nput.before the end of said predetermined time ;nterval.
The DC voltage source SP and the measuring res;stor RM
should be Chosen so that, ~ith the switching contact SCH closed, a voltage of about 1 V appears at the feed-in point of the track sect;on. The clock generator TG
preferably operates at a frequency ;n the range from 0 1 Hz to 10 H~, so that the capacitances and induc-tances of the track can be neglected~ The dwell time of the monostable mult;v;brator MK must be longer than the period of the clock generator TG.
In the normal case, when no rails are broken and the track section GA is unoccupied, large current-value differences occur in the measuring resistor RM in the rhythm of the operation of the switch SCH. These large differences cause the monostable multivibrator MK to be continuously retr;ggered, so that its output MA is constantly at a,low level, the criterion for the unoccupied con-d;t;on of the track section. If a ra;l breakage occurs, or the track section GA is occupied by vehicles, the current-value differences ;n the measuring res;stor RM
wtll become so small that the threshold switch SW no longer changes its state As a result, the monostable multivibrator MK is no longer retriggered and, 9t the H.Uebel-H.Fricke 52-13 . . ' .
'. ' ' ''' , ' , : ' ''" . '' " ,;' ': ' '' .. , ~28~3 end of its dwell time, returns to the stable state~
so that the output MA goes high, thereby indicating a rail breakage or the occupied condition of the track section.
The arrangement according to the invention can be used to advantage as a complement to existing ax.~e counter circuits for indi~cating Long track sections'as un-occupied or occupied if additional broken-rail protec-tion is to be provided and occupancy detection by means of the arrangement according to the invention is not possible, e.g., because the raiLs of the track section are subject to heavy rusting~ This ;s frequently the case on li~tle used lines. If the arrangement according to the invention is combined with an axle-counter arrangement, the output signals of the two arrangements may act on~a common output ~hich also provides an "occupied" ;ndication when a rail has broken within the track section.
To eliminate any disturbances in the time funct;on of the curr~nt~ a correlator may be connected between the measuring amplifier and the differentiator to form an autocorrelation of the time function of the current flowing through the DC voltage source. This, however, requires that the clock generator TG should operate with high precision~ In that case, a crystal-controlled clock generator should be used.
H.Uebel-H,Fricke 52-13 .
Claims (8)
1. Arrangement for monitoring an at least single-rail insulatad track section using a track circuit fed at one end from a DC voltage source, characterized in that at the other end of the track section there is a switching device which electrically interconnects the two rails of the track section at regular time intervals, and that, to derive and output a criterion for the condition of the track section, an evaluation circuit evaluates the amplitude of the AC component flowing through the DC voltage source by comparing it with a threshold value.
2. An arrangement as claimed in claim 1, characterized in that the switching device is controlled by a clock generator at a frequency in the range from 0.1 Hz to 10 Hz.
3. An arrangement as claimed in claim 1, characterized in that prior to the evaluation of the AC component, a correlator forms an autocorrelation of the time function of the current flowing through the DC voltage source.
4. An arrangement as claimed in claim 2, characterized in that prior to the evaluation of the AC component, a correlator forms an autocorrelation of the time function of the current flowing through the DC voltage source.
5. An arrangement as claimed in claim 1, 2, 3 or 4, characterized in that the condition criterion is used to indicate any broken rails within the track section.
6. An arrangement as claimed in claim 1, 2, 3 or 4, characterized in that the condition criterion is used to indicate the unoccupied/occupied condition of the track section.
7. An arrangement as claimed in claim 5, characterized in that, in addition, an occupancy criterion is derived for the track section by means of an axle-counter arrangement.
8. An arrangement as claimed in claim 7, characterized in that the condition criterion and the occupancy criterion are united in a common criterion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3634696.9 | 1986-10-11 | ||
| DE19863634696 DE3634696A1 (en) | 1986-10-11 | 1986-10-11 | Device for monitoring a section of track |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1288853C true CA1288853C (en) | 1991-09-10 |
Family
ID=6311546
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000547559A Expired - Lifetime CA1288853C (en) | 1986-10-11 | 1987-09-23 | Arrangement for monitoring a track section |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU601494B2 (en) |
| CA (1) | CA1288853C (en) |
| DE (1) | DE3634696A1 (en) |
| TR (1) | TR23417A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2418051A (en) * | 2004-09-09 | 2006-03-15 | Westinghouse Brake & Signal | Backup system for detecting a vehicle which may not cause a track circuit to operate. |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2170171A1 (en) * | 1996-02-23 | 1997-08-24 | Cyprien Gauthier | Broken rail position detection |
| AT406856B (en) * | 1998-05-20 | 2000-10-25 | Vae Ag | CIRCUIT ARRANGEMENT FOR MONITORING THE OPERATING CHARACTERISTICS OF RAILWAY TECHNICAL SAFETY DETECTORS |
| DE102006033516A1 (en) * | 2006-07-14 | 2008-01-17 | Siemens Ag | Method for rail-track section occupancy detection, requires comparison of temporal variation of electrical parameter with threshold value |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3534708A1 (en) * | 1985-09-28 | 1987-04-02 | Ivv Ingenieurgesellschaft Fuer | TRACK CIRCUIT WITH OR WITHOUT INSULATION FOR RAILWAY SYSTEMS |
| DE3723877A1 (en) * | 1987-07-18 | 1989-01-26 | Standard Elektrik Lorenz Ag | CIRCUIT ARRANGEMENT FOR TRACK CLEARANCE |
-
1986
- 1986-10-11 DE DE19863634696 patent/DE3634696A1/en active Granted
-
1987
- 1987-09-23 CA CA000547559A patent/CA1288853C/en not_active Expired - Lifetime
- 1987-09-28 AU AU78988/87A patent/AU601494B2/en not_active Expired
- 1987-10-09 TR TR69887A patent/TR23417A/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2418051A (en) * | 2004-09-09 | 2006-03-15 | Westinghouse Brake & Signal | Backup system for detecting a vehicle which may not cause a track circuit to operate. |
| US7523893B2 (en) | 2004-09-09 | 2009-04-28 | Westinghouse Brake And Signal Holdings Limited | Train detection |
Also Published As
| Publication number | Publication date |
|---|---|
| AU601494B2 (en) | 1990-09-13 |
| DE3634696C2 (en) | 1990-06-07 |
| AU7898887A (en) | 1988-04-14 |
| DE3634696A1 (en) | 1988-04-14 |
| TR23417A (en) | 1989-12-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |