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WO1997030878A1 - Detection de la position de rails casses par mesure des proprietes electriques du ballast - Google Patents

Detection de la position de rails casses par mesure des proprietes electriques du ballast Download PDF

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Publication number
WO1997030878A1
WO1997030878A1 PCT/CA1997/000117 CA9700117W WO9730878A1 WO 1997030878 A1 WO1997030878 A1 WO 1997030878A1 CA 9700117 W CA9700117 W CA 9700117W WO 9730878 A1 WO9730878 A1 WO 9730878A1
Authority
WO
WIPO (PCT)
Prior art keywords
rails
segment
electrical property
broken
ballast
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.)
Ceased
Application number
PCT/CA1997/000117
Other languages
English (en)
Inventor
Cyprien Gauthier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chemin De Fer Qns & L
Original Assignee
Chemin De Fer Qns & L
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to US08/607,487 priority Critical patent/US5680054A/en
Priority claimed from US08/607,487 external-priority patent/US5680054A/en
Application filed by Chemin De Fer Qns & L filed Critical Chemin De Fer Qns & L
Priority to AU17155/97A priority patent/AU1715597A/en
Publication of WO1997030878A1 publication Critical patent/WO1997030878A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L23/00—Control, warning or like safety means along the route or between vehicles or trains
    • B61L23/04—Control, warning or like safety means along the route or between vehicles or trains for monitoring the mechanical state of the route
    • B61L23/042—Track changes detection
    • B61L23/044—Broken rails

Definitions

  • the present invention relates to a method and apparatus for locating a position of a break in one of a pair of rails in an electrically isolated segment of a railroad. More particularly, the invention relates to such a method and apparatus in which an electrical property of a ballast medium extending between the pair of rails is measured to determine the position of the rail break.
  • a broken rail in a railroad represents a major danger in railroad traffic.
  • a broken rail may be imperceptible to the eye, but when a loaded train passes over the broken rail, it may cause a derailment of the train resulting in extensive damage, either to passengers or cargo, or to the environment as a result of cargo spills. Rapid and precise rail break detection is thus important to railroad operations and management.
  • the traditional method of railroad integrity detection has been to send a low voltage pulsed DC current down one rail and back through the opposed rail in an electrically isolated segment (also referred to as a block) of the railroad.
  • the segment may have a length of about 0.1 to 5 kilometers and is electrically isolated from contiguous or adjoining segments.
  • a series contiguous segments form a section for signaling purposes (known as a controlled block) and may have a length of 10 to 20 km.
  • the term isolated is used in this specification instead of insulated because the rails are not electrically insulated with respect to the ballast or ground to which they are mounted.
  • the presence or absence of current was detected to confirm that the rails were conducting and not broken or shorted at some point over the segment.
  • the primary object of the traditional method was to provide a check of the block by checking the integrity of the rail. By inserting an electrical code signal at one end of the block and decoding the signal received at the other end of the block, it can then be considered safe for a train to engage itself in this block.
  • the truck When a train has its truck of wheels on the rails, the truck conducts electricity and provides a short across the rails. For example, when the voltage is applied at one end of the segment with a terminal resistance at the other end, the presence of a train is detected at the voltage source end by measuring an increase in current flow, and at the other end by measuring a drop in voltage across the terminal resistance.
  • the known method is only capable of checking continuity of the entire segment.
  • Such inspection could be visual or possibly also electrical, i.e. running a vehicle with insulated wheels so the rail is not shorted and measuring voltage between both front wheels and analog meter inside the vehicle will indicate the presence of the code between left and right rails. The meter will lose its reading when the vehicle runs outside the block or if the rail is broken between the vehicle and the source of the code..
  • Such testing is time consuming, and may prove unsuccessful either due to limitations of the test (visual inspection is difficult) or due to the fact that the break has rejoined due to thermal expansion.
  • it can be very expensive to dispatch a test crew to the railroad segment to carry out the time consuming test.
  • a method for detecting a position of a break in at least one of a pair of rails in an electrically isolated rail segment of a railroad comprising the steps of: measuring an electrical property in a ballast between the rails of the segment from one end thereof when one of the rails in the segment is not broken; measuring an electrical property in a ballast between the rails of the segment from one end thereof when one of the rails in the segment is broken; and calculating a position of the break as a function of the measured ballast electrical property of the segment when the segment is broken and when the segment is not broken.
  • the electrical property of the ballast in the segment or block is different when one of the rails in the segment is broken.
  • the calculation of the position of the rail break requires knowledge of the ballast electrical property before the break. Since the ballast electrical property can vary greatly under different moisture and weather conditions, the measurement of the ballast electrical property must be done as often as may be required under the climatological circumstances, e.g. every few minutes.
  • an apparatus for detecting a position of a break in at least one of a pair of rails in an electrically isolated rail segment of a railroad comprising: means for providing an electrical test signal between rails of the segment at one end thereof; measurement means for detecting the test signal and measuring an electrical property of a ballast interconnecting the rails; position calculating means for calculating a position of a break in one of the rails as a function of the measured electrical property when the rails are free of a break and when one of the rails is broken.
  • the electrical property is resistance or conductivity
  • the test signal is simply a DC voltage.
  • the DC voltage may be pulsed, e.g. 75, 120 or 180 pulses per minute.
  • a sine wave signal can also be used.
  • FIGURE 1 is a graph of current versus distance along the segment in the case of a rail car moving along the track and a broken rail at some point along the segment;
  • FIGURE 2 is a schematic block electrical diagram of an electrically isolated segment provided w ⁇ ⁇ h a testing circuit according to the preferred embodiment; and
  • FIGURE 3 is a flow chart of the method according to the preferred embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
  • a railroad segment comprises a pair of rails 10 and 11 which are electrically cut off from contiguous segments of the railroad.
  • the segment shown has a distance D.
  • a signal generator and control circuit 12 sends a signal into the rails 10 and 11 and the current meter 14 is connected in series with the circuit to measure current flow.
  • a decoder and controller circuit 16 is connected across the rails 10 and 11 and detects the signal sent along the rails for signaling control as is known in the art.
  • a circuit is thus provided having a path leading from signal control circuit 12 to current meter 14 to rail 10 to controller circuit 16 through an internal terminal resistance in controller 16 to rail 11 back to signal control circuit 12.
  • the terminal resistance provides a noticeable drop in current measured as a rail car shorts out the terminal resistance at the end of the section near the controller 16.
  • the decoder and controller circuit 16 differs from conventional circuits in that it responds to a special code sent by the signal control circuit 12 by disconnecting any load, i.e. the terminal resistance, from the rails 10 and 11 for a predetermined period of time such as one second. During this one second time period, the signal control circuit 12 applies a low voltage DC test signal of approximately one volt between the rails and the current detector 14 measures the small amount of current passing between rails 10 and 11 through the ballast 13. This low level of current I ⁇ is recorded by current recorder 18.
  • the current recorder 18 also examines the current measurement from meter 14 when a signal code is being sent through rails 10 and 11 and across the terminal resistance in the controller circuit 16 to confirm that the current level is normal.
  • the normal rail signal current, I s is the current passing through the rails and terminal resistance when no car is on the segment and no rail break is present for a given signal voltage. If the current level is much greater than the normal rail signal current, this means that the circuit has been shorted by a railroad car present on rails 10 and 11 at some point on the segment.
  • the current measured will be the maximum current Id which the control circuit 12 will deliver and at the remote end where the decoder 16 is located, a short will result in current lc.
  • the current will increase slightly and substantially linearly to current level Id since the resistance of rails 10 and 11 is now included in the circuit.
  • Reference numeral 15 indicates a break in the rail 11.
  • rail 10 will be at the potential set by signal controller circuit 12.
  • Current will flow from rail 10 only across the ballast 13 as indicated by the arrows to the portion of rail 11 from the break 15 extending back to the end where the connection signal control circuit 12 is connected.
  • This ballast current is a small fraction of the normal rail signal current but is large enough to measure.
  • Signal control circuit 12 applies the low voltage DC test signal applied to the rails 10 and 11 during the one second period while the controller circuit 16 disconnected any load across the rails, and the current I is measured by meter 14.
  • the fraction of the current passing indicates approximately the fraction of the length of the rail 11 leading up to the break with respect to the entire length of the segment D.
  • the signal control circuit sends an open circuit code through rails 10 and 11 which, when decoded by the decoder and controller circuit 16, causes the load at the decoder end of the segment to be disconnected for a period of one second.
  • the open circuit signal code may be, for example, a special pulse frequency or pulse duration.
  • a low voltage DC test pulse signal applied to the rails 10 and 11 by the signal control circuit 12 has its current measured by current detector 14 and this I current value is recorded by current recorder as the recorded value for the future I/Ifc> calculation.
  • This ballast current measurement will change as the weather changes, namely the ballast current will increase if the ballast is moist and will decrease when dry or frozen.
  • an alarm message is sent to a central station using transmitter 19.
  • the alarm message identifies the nature of the alarm and the calculated Pos value. Additionally, the current values I, I , I s , I c and I3 may also be transmitted.
  • the measured current values I ⁇ , I s , I c and I3 can be sent by radio transmitter after every line interval T, to a central station for central monitoring.
  • the information transmitted can provide the central station with information on the position of trains and, most importantly, in accordance with the present invention a calculation of the position of a rail break can be obtained in order to dispatch a repair crew and, if possible, reroute rail traffic to avoid the rail break.
  • the open circuit condition may only be detected when temperature drops. For example, if a rail is fractured by thermal expansion and contraction, the rail may be cracked, yet it may still conduct since the temperature is relatively warm. In the winter time, it may remain connected and conductive until the ambient temperature reaches an extreme cold value which may not occur until very early in the morning. By 10 am., it is possible that the temperature has increased enough to cause the rail to conduct again. If the rail break was to be located using normal conductivity testing, a test crew dispatched in the morning would not have time to be organized and sent to a remote segment of the railroad in time to inspect the entire length by 10 am. Thus, one would never find the rail break by ordinary conductivity testing.
  • the position of the rail break is calculated as soon as it is detected. Even if the conductivity of the rail has been restored by thermal expansion, a crew dispatches to a particular location within the segment will likely only need to scan a length of between 50 to 200 meters of track in order to locate the actual rail break. With such concentration of efforts, a careful visual inspection as well as other forms of rail inspection can be efficiently undertaken.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Train Traffic Observation, Control, And Security (AREA)

Abstract

La position d'une cassure dans au moins une paire de rails dans un segment de rail isolé électriquement d'une voie ferrée est déterminée par mesure du courant traversant le ballast, entre les rails du segment, à partir d'une extrémité dudit segment, lorsqu'un des rails se trouvant dans le segment n'est pas rompu et ensuite lorsque le rail est rompu. Une position de la cassure peut être calculée en fonction du courant du ballaste. Une approximation linéaire utilisant le rapport entre le courant du ballaste lorsque le rail est cassé et le courant du ballaste lorsque le rail est intact, multiplié par la distance du segment de rail, à partir d'une extrémité, donne une approximation satisfaisante de l'emplacement de la cassure du rail.
PCT/CA1997/000117 1996-02-23 1997-02-21 Detection de la position de rails casses par mesure des proprietes electriques du ballast Ceased WO1997030878A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US08/607,487 US5680054A (en) 1996-02-23 1996-02-27 Broken rail position detection using ballast electrical property measurement
AU17155/97A AU1715597A (en) 1996-02-23 1997-02-21 Broken rail position detection using ballast electrical property measuremen

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CA002170171A CA2170171A1 (fr) 1996-02-23 1996-02-23 Detection de l'emplacement d'un rail rompu
CA2,170,171 1996-02-23
US08/607,487 US5680054A (en) 1996-02-23 1996-02-27 Broken rail position detection using ballast electrical property measurement

Publications (1)

Publication Number Publication Date
WO1997030878A1 true WO1997030878A1 (fr) 1997-08-28

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA1997/000117 Ceased WO1997030878A1 (fr) 1996-02-23 1997-02-21 Detection de la position de rails casses par mesure des proprietes electriques du ballast

Country Status (3)

Country Link
AU (1) AU1715597A (fr)
CA (1) CA2170171A1 (fr)
WO (1) WO1997030878A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007067708A1 (fr) * 2005-12-08 2007-06-14 General Electric Company Systeme et procede pour detecter une interruption de rails/ la presence d'un vehicule
FR2994411A1 (fr) * 2012-06-27 2014-02-14 Alstom Transport Sa Procede de surveillance d'une voie ferree et dispositif adapte pour la mise en oeuvre du procede

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105984476B (zh) * 2015-02-03 2018-09-11 兰州铁山众龙机电有限公司 一种非电气化铁道半自动闭塞断轨监测系统

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3634696A1 (de) * 1986-10-11 1988-04-14 Standard Elektrik Lorenz Ag Einrichtung zur ueberwachung eines gleisabschnittes
DE3738696A1 (de) * 1987-11-14 1989-05-24 Standard Elektrik Lorenz Ag Verfahren und einrichtung zur ortung eines schienenbruches
WO1991011356A1 (fr) * 1990-01-25 1991-08-08 Eb Signal Ab Systeme de circuit de voie
DE4332888A1 (de) * 1993-09-22 1995-03-30 Elpro Ag Verfahren und Anordnung zur Ermittlung und Meldung des elektrischen Zustandes von Spannungsdurchschlagsicherungen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3634696A1 (de) * 1986-10-11 1988-04-14 Standard Elektrik Lorenz Ag Einrichtung zur ueberwachung eines gleisabschnittes
DE3738696A1 (de) * 1987-11-14 1989-05-24 Standard Elektrik Lorenz Ag Verfahren und einrichtung zur ortung eines schienenbruches
WO1991011356A1 (fr) * 1990-01-25 1991-08-08 Eb Signal Ab Systeme de circuit de voie
DE4332888A1 (de) * 1993-09-22 1995-03-30 Elpro Ag Verfahren und Anordnung zur Ermittlung und Meldung des elektrischen Zustandes von Spannungsdurchschlagsicherungen

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007067708A1 (fr) * 2005-12-08 2007-06-14 General Electric Company Systeme et procede pour detecter une interruption de rails/ la presence d'un vehicule
US7268565B2 (en) 2005-12-08 2007-09-11 General Electric Company System and method for detecting rail break/vehicle
CN101326091B (zh) * 2005-12-08 2011-03-30 通用电气公司 用于检测断轨/交通工具的系统和方法
FR2994411A1 (fr) * 2012-06-27 2014-02-14 Alstom Transport Sa Procede de surveillance d'une voie ferree et dispositif adapte pour la mise en oeuvre du procede

Also Published As

Publication number Publication date
AU1715597A (en) 1997-09-10
CA2170171A1 (fr) 1997-08-24

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