METHOD AND SYSTEM FOR REGULATING GUIDED VEHICLE HEADWAYS

Abstract

A method and system for managing traffic of guided vehicles over a railway network include a first ATS system for regulating traffic of guided vehicles over a first regulation domain of the network and a second ATS system configured for regulating traffic of guided vehicles over a second regulation domain. The regulation domains have a common boundary and at least one track connects a first position within the first regulation domain to a second position within the second regulation domain. The second ATS system detects limited traffic capacity at the second position and automatically computes, as a function of the detected limited traffic capacity, a target headway between two successive guided vehicles crossing the common boundary for entering the second regulation domain. The first ATS system automatically determines, from the received target headway, a reference timetable, complying with the received target headway, for the first regulation domain.

Claims

1. A system for managing traffic of guided vehicles within a railway network, the system comprising: a first ATS system configured for regulating the traffic of the guided vehicles over a first regulation domain of the railway network; a second ATS system configured for regulating the traffic of the guided vehicles over a second regulation domain; the first and second regulation domains having a common boundary and at least one track connecting a first position located within the first regulation domain to a second position located within the second regulation domain; said second ATS system configured for detecting a limited traffic capacity at the second position and for automatically computing, as a function of the detected limited traffic capacity, a target headway to be applied by said first ATS system between two successive guided vehicles having to cross the common boundary for entering the second regulation domain, and for automatically sending said target headway to said first ATS system; and said first ATS system configured for automatically determining, from said received target headway, a reference timetable for the first regulation domain, said reference timetable satisfying said received target headway.

2. The system according to claim 1, wherein said target headway is determined for all couples of two successive guided vehicles having to cross the common boundary within a predetermined timeframe.

3. The system according to claim 1, wherein said second ATS system is configured for automatically measuring, for a specific number of successive guided vehicles, a delay, with respect to a nominal timetable, of each of the successive guided vehicles when passing or crossing the second position.

4. The system according to claim 3, wherein said specific number is greater than or equal to 3 and is automatically determined by said second ATS system as a function of: a duration of one or several peak hours and of one or several off-peak hours at the second position; a nominal headway defined for each guided vehicle crossing the second position during a peak hour; a predefined timeframe.

5. The system according to claim 3, wherein said second ATS system is configured for using a regression analysis for determining whether successive guided vehicle delays lead to a limited traffic capacity at the second position.

6. The system according to claim 5, wherein said second ATS system includes a traffic saturation estimation algorithm configured for applying a least squares method using a linear fit for fitting a set of measured delays, and a slope or gradient of a resulting line fitting the measured delays is used by said second ATS system for determining whether or not a limited traffic capacity will occur.

7. The system according to claim 6, wherein a value of said target headway is predetermined as a function of said slope or gradient.

8. The system according to claim 1, wherein a target headway value defined by an operator and received as an input by said first ATS system is configured for superseding any target headway value transmitted by said second ATS system.

9. A method for managing traffic of guided vehicles over a railway network, the method comprising: providing a first ATS system for regulating the traffic of the guided vehicles over a first regulation domain; providing a second ATS system for regulating the traffic of the guided vehicles over a second regulation domain; the first and second regulation domains sharing a common boundary and at least one track connecting a first position located within the first regulation domain to a second position located within the second regulation domain; using the second ATS system to detect a limited traffic capacity at a second position; using the second ATS system to automatically compute as a function of the detected limited traffic capacity, a target headway for a couple of successive guided vehicles having to cross the common boundary for entering the second regulation domain; using the second ATS system to automatically send the target headway to the first ATS system; and using the first ATS system to receive the target headway and to automatically determine from the received target headway a reference timetable for the first regulation domain, the reference timetable complying with the target headway defined by the second ATS system.

10. The method according to claim 9, which further comprises determining the target headway for all couples of successive guided vehicles having to cross the common boundary within a predetermined timeframe.

11. The method according to claim 9, which further comprises carrying out the detecting step by automatically measuring, for a specific number of successive guided vehicles, a delay, with respect to a nominal timetable, of each of the successive guided vehicles when passing or crossing the second position.

12. The method according to claim 11, which further comprises using the second ATS system to automatically determine the specific number as a function of: a duration of one or several peak hours and a duration of one or several off-peak hours at the second position; a nominal headway defined for each guided vehicle crossing the second position during a peak hour; a predefined timeframe.

13. The method according to claim 11, which further comprises using a regression analysis for determining whether successive guided vehicle delays lead to a limited traffic capacity at the second position.

14. The method according to claim 13, which further comprises using a traffic saturation estimation algorithm configured for applying a least squares method using a linear fit for fitting a set of measured delays, and using the second ATS system to utilize a slope or gradient of a resulting line fitting the measured delays for determining whether or not a limited traffic capacity will occur.

15. The method according to claim 14, which further comprises predetermining a value of the target headway as a function of the slope or gradient.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0046] FIG. 1 is a schematic representation of a preferred embodiment according to the invention;

[0047] FIG. 2 is a flowchart of a preferred method according to the invention; and

[0048] FIG. 3 is a graphical illustration of tracked delays for successive guided vehicles.

DETAILED DESCRIPTION OF THE INVENTION

[0049] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a schematically illustrated portion of a railway network divided in geographical areas corresponding to regulation domains and in which the guided vehicle traffic or flow on each regulation domain is managed by an ATS system. More particularly, FIG. 1 shows a first regulation domain R1 managed by a first ATS system ATS_1 and a second regulation domain R2 managed by a second ATS system ATS_2. The first regulation domain R1 and the second regulation domain R2 share a common boundary B.

[0050] A track T connects a first position within the first regulation domain R1, for instance the position of a first station 10, to a second position located within the second regulation domain R2, for instance the position of a second station 20. Guided vehicles 3 are moving from the first position (upstream) to the second position (downstream) and thus have to cross the common boundary B when moving from the first regulation domain R1 to the second regulation domain R2.

[0051] An ATS system according to the invention, e.g. the first or second ATS system ATS_1, ATS_2, includes a processor, a memory, and communication devices. The memory, or an external database of the ATS system, may include a set of traffic regulation criteria, a nominal timetable, a reference timetable based on the nominal timetable, and one or several algorithms based on the traffic regulation criteria, and optionally one or several predefined values of target headways. The ATS system is configured for applying the one or several algorithms to acquired or received traffic data (typically circulation and configuration data) for continuously or periodically updating its reference timetable and determining regulation data that are then applied to devices located within its regulation domain, e.g. interlocking mechanisms, for controlling the guided vehicle traffic over its regulation domain.

[0052] FIG. 2 schematically illustrates the method according to the invention for managing the traffic of guided vehicles moving from the first regulation domain R1 to the second regulation domain R2 as illustrated by FIG. 1.

[0053] At step 201, the second ATS system ATS_2, i.e. the downstream ATS system, detects an issue 4 that may lead to a limited guided vehicle traffic capacity on its regulation domain, notably at the second position.

[0054] For this purpose and preferentially, the second ATS system ATS_2 is configured for automatically estimating, for a specific number TC of successive guided vehicles, the delay of each of the successive guided vehicles when passing or crossing the second point, wherein each of the delays is measured with respect to the nominal timetable of the second ATS system ATS_2. The delays which have been measured thus form a set of delays.

[0055] Preferentially, the second position is a point on the railway network of the second regulation domain R2 wherein a limitation of the traffic capacity would lead to a maximum congestion of guided vehicles within the second regulation domain or would have the most severe consequences, notably with respect to guided vehicle delays within the second regulation domain R2. Such a point is for instance a junction.

[0056] In particular, the specific number TC of successive guided vehicles having a respective delay which is tracked by the second ATS system ATS_2 is greater or equal to 3. This specific number is preferentially automatically determined by the second ATS system ATS_2 as a function of: [0057] a duration of one or several peak hours and of one or several off-peak hours at the second position; [0058] a nominal headway defined for each couple of directly successive guided vehicles having to cross the second position during a peak hour; [0059] the predefined timeframe, i.e. the value of the period of time for which the optimized timetable is computed.

[0060] FIG. 3 illustrates the respective delays R1-R7 measured by the second ATS system ATS_2 for 7 successive guided vehicles C1 to C7, each delay Ri, i=1 to 7, indicating the delay of the guided vehicle Ci at the second position with respect to the nominal timetable, i.e. with respect to the time at which it should have crossed or passed the second position according to its nominal schedule.

[0061] Preferentially, the second ATS system ATS_2 is configured for using a regression analysis for determining whether the successive guided vehicle delays that have been measured will lead to a limited traffic capacity (i.e. a traffic saturation) at the second position. For instance, the second ATS system ATS_2 includes a traffic saturation estimation algorithm configured for applying a least squares method to the set of measured delays, using for instance a linear fit for fitting the set of measured delays, wherein the slope or gradient G of the resulting line L that fits the measured delays is used by the second ATS system ATS_2 for determining whether a limited traffic capacity will occur or not. In particular, a limited traffic capacity is detected at the second position of the second regulation domain R2 if the slope or gradient of the line L resulting from the application of the least squares method to the set of delays is greater than a predetermined gradient threshold (hereafter “GT”) value, otherwise no limited traffic capacity (i.e. no traffic saturation) is detected at the second position by the second ATS system ATS_2. Preferentially, the second ATS system ATS_2 includes, e.g. in its memory or in a database, a predetermined GT value defined for each specific number TC that might be used for the regression analysis. The values stored in the system according to the invention for each couple (TC, GT) will directly influence the performance of the limited traffic capacity detection.

[0062] Preferentially, the second ATS system ATS_2 includes a set of n traffic saturation estimation algorithms A1, . . . , An, wherein the A1 to An traffic saturation estimation algorithms are configured for running in parallel in order to detect a limited traffic capacity at the second position. Each traffic saturation estimation algorithm Ai, i=1, . . . , n, is configured for tracking the delays of a given number TCi of guided vehicles, which is different for each of the traffic saturation estimation algorithms. For each traffic saturation estimation algorithm Ai, a given predetermined gradient threshold GTi is defined and used by the second ATS system for determining whether there is or not traffic saturation at the second position. Therefore, a couple (TCi,GTi) is defined for each traffic saturation estimation algorithm Ai, wherein each couple (TCi,GTi) is predefined in a memory or database of the system according to the invention. A severity Si is associated to each couple (TCi,GTi), wherein the severity Si represents a degree or level of traffic congestion, wherein the severities Si are classified according to an increasing level of traffic congestion with S1<S2< . . . <Sn, wherein S1 represents the lowest level of traffic congestion and Sn the highest level of traffic congestion.

[0063] According to this embodiment, and for instance, A1 tracks the delays for TC1=4 successive guided vehicles, A2 tracks the delays for TC2=6 successive guided vehicles, and A3 tracks the delays for TC3=10 successive guided vehicles. Each of the traffic saturation estimation algorithms A1-A3 proceeds to a fit, by using the regression analysis, of the set of measured delays as shown in FIG. 3, obtaining therefore a line L1 for A1, a line L2 for A2 and a line L3 for A3. As previously explained, each traffic saturation estimation algorithm Ai compares then the slope of the line Li to the predetermined gradient threshold GTi associated with the given number TCi in order to determine whether the value of the slope is greater than the predetermined gradient threshold GTi value or not. If yes, then a congestion occurs, the severity of which is given by the value Si; otherwise, no congestion is detected.

[0064] At step 202, if a limited traffic capacity has been detected by the second ATS system ATS_2, then the latter automatically computes a target headway defined for each couple of successive guided vehicles that are going to enter its regulation domain according to its reference timetable, the target headway being determined as a function of the detected limited guided vehicle traffic capacity, for guided vehicles having to enter the second regulation domain within a predetermined timeframe, and defined preferentially at the common boundary B, i.e. defined for a position of a second guided vehicle located at the common boundary (wherein the second guided vehicle follows directly a first guided vehicle, wherein the target headway has been defined for the couple formed by the first and second guided vehicle), otherwise the, defined for the entering guided vehicle. In particular, the second ATS system ATS_2 computes a single target headway for all couples of directly successive guided vehicles having to cross the common boundary B within the predetermined timeframe. Alternatively, the second ATS system ATS_2 computes for each couple of directly successive guided vehicles having to cross the common boundary B within the predetermined timeframe a specific target headway (several couples of directly successive guided vehicles might have thus a different specific target).

[0065] For instance, when the slope or gradient obtained by running the traffic saturation estimation algorithm is greater than the predetermined GT value defined for the traffic saturation estimation algorithm, then the second ATS system ATS_2 automatically selects a predetermined value for the target headway. The value might be predetermined as a function of the slope or gradient, e.g. increasing with an increasing slope or gradient. If the slope or gradient obtained by running the traffic saturation estimation algorithm is smaller or equal to the predetermined GT value, then no limited traffic capacity is detected and the target headway value is not computed.

[0066] In the case of the second ATS system ATS_2 including a set of n traffic saturation estimation algorithms A1, . . . , An, running in parallel, then the downstream ATS system ATS_2 preferentially includes a plurality of predetermined target headway values TH1 to THn, wherein for each severity Si, one predetermined target headway value THi is associated, wherein the value of the predetermined target headway increases with increasing severities, i.e. T1<T2< . . . <Tn. When multiple congestions are detected at approximately the same time by running in parallel the n traffic saturation estimation algorithms, then the second ATS system ATS_2 automatically determines which severity Si among the severities associated to the detected multiple congestions represents the highest level of congestion, and then automatically selects the predetermined target headway value THi defined for the severity Si indicating the highest level of congestion. If no congestion is detected, then no predetermined target value is selected, and traffic regulation is handled according to the usual way for both the first and second ATS systems, i.e. free of a communication by the second ATS system of the predetermined target value to the first ATS system.

[0067] For instance, in the case of the traffic saturation estimation algorithm A1, A2 and A3, the second ATS system ATS_2 might have obtained, through the algorithm A1, that the slope of the line L1 is greater than the predetermined gradient threshold GT1, through the algorithm A2, that the slope of the line L2 is smaller than the predetermined gradient threshold GT2, and through the algorithm A3, that the slope of the line L3 is greater that the predetermined gradient threshold GT3. It means that two congestions are detected by the second ATS system ATS_2, one through the algorithm A1 and another one through the algorithm A3. Then the second ATS system determines which is the severity Si associated to the couple (TCi,GTi) that represents the highest level of congestion, and will select the predetermined target headway THi associated to the severity Si. In the present case, the couples (TCi,GTi) have been predetermined so that the severity S3>S1, and therefore, the second ATS system ATS_2 will automatically select the predetermined target headway TH3 for sending the latter to the first ATS system.

[0068] At step 203, the second ATS system ATS_2 automatically sends or communicates to the first ATS system ATS_1 the target headway(s) (i.e. the target headway value(s), e.g. the value of the predetermined target headway previously selected). In particular, if the second ATS system ATS_2 detects an end of the limitation of the traffic capacity, because for instance, the issue has been resolved, or the slope or gradient becomes smaller or equal to the predetermined GT value, then the second ATS system ATS_2 is configured for sending a signal configured for cancelling the target headway.

[0069] At step 204, the first ATS system ATS_1 receives the target headway(s) and automatically determines from the latter a reference timetable for the first regulation domain. According to the present invention, the reference timetable is configured for implementing a headway regulation complying, at the common boundary, with the target headway determined and sent by the second ATS system ATS_2, notably for all couples of directly successive guided vehicles having to cross the common boundary within the predetermined timeframe. According to the present invention, achieving this target headway value defined between successive guided vehicles crossing the common boundary B has priority over all other regulation criteria of the first ATS system when determining the reference timetable. Thus, the first ATS system ATS_1 will do a best effort to adhere to the target headway value that has been received and thus assigned when determining its reference timetable, notably at least until the signal configured for cancelling the target headway is received. Indeed, at the reception of the signal configured for cancelling the target headway value, the first ATS system ATS_1 automatically stops taking into account the target headway(s) for calculating its reference timetable.

[0070] Optionally, the first ATS system ATS_1 might be configured for receiving a target headway value defined by an operator and received as input in its algorithm, notably in case of a detection of the issue by the operator or a control center. When a target headway value is defined by the operator and received as input, then the value is configured for superseding any target headway value transmitted by the second ATS system ATS_2.

[0071] In conclusion, the present invention proposes a system and a method that considerably reduce the workload of operators of ATS systems, notably in stressing situations when incidents impacting train traffic capacity occur. In particular, the present invention proposes to use traffic saturation estimation algorithms that enable to detect different levels of limitations of the traffic capacity and to link each of the levels to a predetermined target headway value defined between successive guided vehicles at the common boundary. According to the present invention, headway regulation at a common boundary of an upstream ATS system might be imposed, by using the target headway value, by a downstream ATS system that detects a limitation of guided vehicle traffic within its regulation domain.