Abstract
A method and an apparatus for a train control installation are disclosed, and are based on the absolute permissive block concept. The train control installation employs a plurality of generic absolute block signal units (ABSU), wherein each signal unit includes means for detecting the crossing of a train passed a discrete point, means for exchanging data with adjacent ABSUs, means for generating and communicating a movement authority limit to a train, means for generating and displaying a signal indication, and means for enforcing a stop aspect. The train control installation can be used in conjunction with a communication based train control (CBTC) system to provide a degraded mode of operation without impacting the availability and the reliability of the CBTC system. Further, the train control installation has a self-healing feature to maintain train service during an ABSU failure.
Claims
1. A wayside train control installation that includes a plurality of signal control devices that operate in conjunction with a Communication Based Train Control (CBTC) system, wherein each signal control device controls the movement of a train into an associated track section, wherein said plurality of signal control devices operate autonomously of the CBTC system to provide at least one degraded mode of operation during CBTC failure, and wherein a failure in said wayside train control installation has no impact on normal CBTC operation.
2. A wayside train control installation that includes a plurality of signal control devices, wherein each signal control device controls the movement of a train into an associated absolute permissive block, and wherein a signal control device comprises: a communication module to communicate with a train approaching the location of the associated absolute permissive block, wherein the approaching train communicates its operating state to the device, means for determining the operating state of the approaching train, and control means to precondition the device to fail in a plurality of failure states based on the operating state of the approaching train.
3. A train control system that includes a configuration of a plurality of signal control devices, wherein each signal control device controls the movement of a train into an associated absolute permissive block, wherein a signal control device communicates with at least one adjacent signal control device, wherein upon the failure of one of said plurality of signal control devices, the train control system is reconfigured without the failed device and by combining the absolute permissive block associated with the failed device with the absolute permissive block associated with the device in the approach to the failed device.
4. A train control system that includes a plurality of signal control devices, wherein each signal control device controls the movement of a train into an associated absolute permissive block, wherein a signal control device communicates with at least one adjacent signal control device, wherein the signal control device acquires data from a train crossing into the associated absolute permissive block, and wherein the signal control device communicates the acquired data to at least one adjacent signal control device.
5. A train control system that includes a plurality of wayside signal control devices, wherein a signal control device tracks the number of trains operating in an associated track section, wherein each train is identified by a train signature that includes the number of axles in the train, and wherein a signal control device comprises: an axle counter located at the entrance of said track section for detecting the number of axles of a train passing its location, at least one of a radio communication module and a data communication module for exchanging data with at least one adjacent signal control device, a processor module with a computer-readable medium encoded with a computer program, a computer program segment that tracks the trains operating within said track section, and a computer program segment that generates and transmits a movement authority limit to a train approaching the entrance location of said track section.
6. A train control system as recited in claim 5, wherein a wayside signal control device further comprises a transponder reader.
7. A train control system as recited in claim 5, wherein a wayside signal control device further comprises at least one of a wayside signal and an automatic train stop.
8. A train control system as recited in claim 5, wherein said movement authority limit is transmitted to the approaching train via a transponder.
9. In a train control system that includes a plurality of train control devices, wherein each train control device controls the movement of a train into an associated track section, wherein each train control device includes at least one of a radio module and a transponder reader to receive train operating status from a train approaching the associated track section, wherein each train control device includes a processor module with a computer-readable medium encoded with a computer program to control the operation of the device, and wherein at least one of said plurality of train control devices controls a wayside signal, a method to control the failure state of the at least one of said train control devices comprising the following steps: receiving the operating status of the approaching train, preconditioning the device to fail into a first failure state upon receiving a first operating status from the approaching train, wherein during the first failure state the wayside signal displays a permissive aspect, and preconditioning the device to fail into a second failure state upon receiving a second operating status from the approaching train, wherein during the second failure state the wayside signal display a stop aspect.
10. In a train control system that includes a plurality of signal control devices and a zone controller, wherein each signal control device is associated with a track section and includes a communication module for the device to communicate with the zone controller and with at least one adjacent signal control device, wherein a signal control device further includes at least one of an axle counter and a transponder reader to receive operational data from trains crossing into the associated track section, a method for initializing the zone controller comprising the following steps: monitoring the movement of trains entering and exiting the track sections associated with said signal control devices, tracking the operational data of trains operating within the track sections, establishing communication between the zone controller and signal control devices upon the recovery of the zone controller from a failure, and communicating operational data of trains operating within track sections from signal control devices to the zone controller.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) These and other more detailed and specific objectives will be disclosed in the course of the following description taken in conjunction with the accompanying drawings wherein:
(2) FIG. 1 is a general block diagram of the Absolute Block Signal Unit (ABSU) in accordance with the preferred embodiment of the invention.
(3) FIG. 2 shows a typical AWS installation that includes three (3) ABSUs that operate autonomously of a zone controller in a “standby” mode in accordance with the preferred embodiment of the invention.
(4) FIGS. 3-18 demonstrate the operation of the AWS installation, including a step by step operation of ABSU-1, ABSU-2 and ABSU-3 in an “active” mode during a zone controller failure.
(5) FIG. 19 shows the AWS operating conditions prior to a failure of a CBTC equipped train.
(6) FIGS. 20-33 demonstrate the operation of the AWS installation, including a step by step operation of ABSU-1, ABSU-2 and ABSU-3 in an “active” mode as a failed CBTC train moves through the AWS territory.
(7) FIG. 34 shows the general approach to implement the ABSU concept at an interlocking location in accordance with the preferred embodiment of the invention.
(8) FIGS. 35 & 36 show the functioning logical modules of an ABSU interlocking configuration for various traffic patterns in accordance with the preferred embodiment of the invention.
(9) FIGS. 37-43 demonstrate a step by step standby mode operation of an ABSU interlocking configuration for a series of train moves along internal interlocking routes in accordance with the preferred embodiment of the invention.
(10) FIGS. 44-55 demonstrate a step by step active mode operation of an ABSU interlocking configuration during a zone controller failure, and for the same series of train moves demonstrated in FIGS. 37-43.
(11) FIGS. 56-61 demonstrate the process to initialize a failed zone controller using data from the ABSUs in accordance with the preferred embodiment of the invention.
(12) FIG. 62 shows the traffic conditions prior to an ABSU failure, wherein CBTC operation is in progress and the ABSUs are operating in a “standby” mode.
(13) FIGS. 63 & 64 demonstrate a step by step standby mode operation of the ABSUs during a single ABSU failure, and the reconfiguration of the AWS in accordance with the preferred embodiment of the invention.
(14) FIG. 65 shows the logic diagram used to precondition an ABSU to fail in one of two failure states based on the operating condition of an approaching train in accordance with the preferred embodiment of the invention.
(15) FIGS. 66-71 demonstrate a step by step active mode operation of the ABSUs during a failure of the zone controller as well as a single ABSU failure, and the reconfiguration of the AWS in accordance with the preferred embodiment of the invention.
(16) FIGS. 72-74 demonstrate a step by step operation of the ABSUs with an overlap function during the movement of a manual train that is operating without speed restriction through the AWS territory in accordance with the preferred embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
(17) The present invention describes a new structure, and/or a new method to implement an Auxiliary Wayside Signal (AWS) system. This new structure is based on the concept of absolute permissive block, and uses an architecture that includes conventional train control equipment to provide the required AWS functions. The proposed AWS system can be integrated with a CBTC installation to provide backup modes of operation, as well as to facilitate the initialization of CBTC equipment (zone controllers and on-board controllers) into CBTC operation. In addition, one of the main characteristics of the proposed AWS system is to be transparent to CBTC operation, and to operate without any impact on CBTC functionalities and availability. Another characteristic of the AWS is to provide a self-healing feature that enables train service to continue in the event of certain AWS failures. The proposed AWS system can also be used as a primary signaling system for simple train control applications, and is designed to provide limited signal protection to manual trains operating without a speed restriction.
(18) To implement the absolute permissive block concept, a new generic structure defined as an Absolute Block Signal Unit (ABSU) is proposed. The architecture of the ABSU employs a number of conventional train control devices that provide basic functions for the operation of the ABSU. These functions include the detection of a train crossing a specific location, communicating with other elements of the AWS system as well as elements of an associated CBTC installation, controlling the movement of a train into an associated absolute permissive block, communicating a movement authority limit (MAL) and/or a civil speed restriction to an approaching train, and detecting certain attributes associated with a train crossing its location.
(19) The preferred embodiment is based on a specific ABSU design that includes a processor module, an axle counter, a transponder reader, an active transponder, a data radio communication module, a wayside signal and associated automatic train stop. Further, the preferred embodiment employs a train identification system that is based on a unique attributes for each train. More specifically, each train is identified by the number of axles in the train consist and an alphanumeric code that includes a fixed field and/or a variable field based on the train's current trip.
(20) The disclosure of the various concepts used by the preferred embodiment is based on a number of operating hypothesis and assumptions. More specifically, it is assumed that under the primary CBTC operation, all trains operating in the CBTC territory are equipped CBTC trains, and that upon a failure of a zone controller, all affected trains will operate with a speed restriction. Also, if a CBTC equipped train fails, it is assumed that it will operate with a speed restriction. The restricted speed is a design choice, but typically train operates at a restricted speed of 10 to 20 mph during a CBTC failure. It is also assumed that under rare operating conditions, a manual train may operate through the CBTC territory without speed restriction and using an absolute block protection from interlocking to interlocking. The safety of operation of the manual train is dependent on compliance with operating rules and procedures, especially the compliance with civil speed limits within the territory. The preferred embodiment includes a design feature that provides a limited protection for a manual train.
(21) Referring now to the drawings where the illustrations are for the purpose of describing the preferred embodiment of the invention and are not intended to limit the invention hereto, FIG. 1 is a block diagram of the general architecture for the Absolute Block Signal Unit 2. The ABSU includes a processing module 4, an axle counter 6, an active transponder 8, a transponder antenna 14, a data radio module 16 with associated antenna 18, and a wayside signal 10 with associated automatic train stop 12. The processor module 4 controls the operation of the ABSU 2, and processes input signals from the axle counter 6, the transponder antenna 14, the automatic train stop 12, as well as data received from the data radio data module 16. Also, the processor module 4 generates data and/or control signals for the active transponder 8, the wayside signal 10, the automatic train stop 12, as well as data to be transmitted via the data radio module 16. The wayside signal 10 could be of the position light type, color light type or color position light type signal. For the preferred embodiment, the wayside signal is a color position light type signal. Further, the automatic train stop 12 could be of the mechanical type with a circuit controller, a magnetic type or a transponder based stop device. For the preferred embodiment, the automatic train stop is of the mechanical type with circuit controller. In addition, the data radio module 16 is of the same type used by an associated CBTC installation to enable the ABSU to communicate with CBTC equipped trains and other CBTC system elements.
(22) Communications between adjacent ABSUs could be through data radio communication, or via a backbone fiber optic network that also interconnect the ABSUs with elements of the CBTC installation, including zone controllers, an ATS subsystem, interlocking control devices, etc. For the preferred embodiment, communications between the ABSUs is via data radio communication. As indicated above, the ABSU can be located at a CBTC radio location in order to leverage the CBTC communication infrastructure (i.e. both radio and fiber optic data communication).
(23) It should be noted that the transponder antenna 14 is physically located in the approach to the ABSU location to enable the processing of train information by the ABSU as the train is approaching its location. Similarly, the active transponder 8 is physically located in the approach to the ABSU location, and could be supplemented by additional transponders or an inductive loop to maintain continuous and smooth train operation. It should also be noted that once a train is identified to an ABSU, its signature will propagate along the line via ABSU to ABSU communication. The data received from the transponder antenna 14 acts as confirmation of the train signature received through ABSU to ABSU communication.
(24) The absolute permissive block concept is based on providing a movement authority to a particular train at a specific location to move for a specific distance or to a specific location. To facilitate the implementation of this concept, the preferred embodiment employs a train identification system that is based on a unique “signature” for each equipped CBTC train. Since it is anticipated that non-equipped trains may operate in the territory, the signature includes two elements, and one of these elements is also present in non-equipped trains. More specifically, the train signature includes a first element that consists of the number of axles in the train consist, and a second element that comprises an alphanumeric code embedded in a transponder mounted on the train. For the preferred embodiment, the alphanumeric code includes two fields, the first field contains a fixed train ID, and the second field includes a trip ID that changes for each train trip. Therefore, for a non-equipped train, only one field (# of train axles) is present in the train signature. The use of the train signature enables the implementation of a number of safety functions, including ensuring that all the cars within a particular train have passed a specific location, tracking a specific train among a “stack” of trains, and facilitating the interfaces with the CBTC installation.
(25) Although the Auxiliary Wayside Signal system operates independently and autonomously of a CBTC system, it is primarily designed to support the operation of a communication based train control installation. As such, it is desirable that the CBTC installation incorporates certain features to facilitate the interfaces with the proposed AWS. More specifically, it is desirable that each CBTC train be equipped with an active transponder that stores a fixed train ID and a variable trip ID. It is also desirable that the train tracking algorithm within the zone controller tracks the number of axles within each train consist. It should be noted that while it is desirable to incorporate the above features into a CBTC system, the proposed AWS system can function without these features. In such case, the train signature will include one element, namely the number of axles in the train consist.
(26) In order to distinguish a failed non-communicating train from a manual unequipped train, the preferred embodiment includes a data field within the variable trip ID that reflects the operating conditions on the train. Information stored in the data field identify if the train is operating with a speed restriction, or operating with a MAL. The absence of proper code in this data field, or the absence of an entire train signature indicates to the ABSUs that the train must be processed as a manual train. Since the train ID is tracked by the AWS system and is communicated from one ABSU to the next, an ABSU can ascertain the operating status of the approaching train upon receiving a communication from the Approach ABSU.
(27) The AWS system includes a plurality of ABSUs that are installed on the right of way, and are interconnected by a fiber optic data communication network, or through data radio communications. The number and spacing between ABSUs is a design choice, and is dependent on the desired operating headway for the AWS system. FIG. 2 shows a typical AWS installation that includes three (3) ABSUs 22, 24 & 26. The AWS system is installed in conjunction with a CBTC system that includes a zone controller 30, a data communication network 20, and onboard CBTC equipment installed on trains 52, 54, 56, 58 & 59. The data communication network 20 provides communication between the zone controller 30 and the CBTC equipped trains, as well as communication between the ABSUs 22, 24 & 26 and between the ABSUs and the CBTC elements. The ABSUs have two modes of operation, a “standby” mode that is in effect when CBTC is operating normally, and an “active” mode when CBTC is experiencing a failure. During the standby mode of operation, an ABSU monitors train operation within an associated absolute permissive block. In that respect, ABSU-1 26 monitors train operation within absolute block 25, and ABSU-2 24 monitors train operation within absolute block 23. Also, to facilitate the description of the preferred embodiment, with respect to ABSU-2 24, ABSU-1 26 is defined as the Approach ABSU, and ABSU-3 22 is defined as the ABSU Ahead.
(28) Each ABSU includes a data stack defined as “protected stack” that stores the number of trains as well as the signature of each train operating within the associated absolute permissive block. The stack is of the first-in-first-out type, and is used to control the movements of trains during CBTC failures. As such, protected stack 42 is associated with ABSU-1 26, protected stack 44 is associated with ABSU-2 24, and protected stack 46 is associated with ABSU-3 22. In addition, each ABSU includes an “Approaching Train” data field that stores the signature information associated with the first train approaching the ABSU location. As such approaching train data field 32 includes the signature information for the train approaching ABSU-1 26, approaching train data field 34 includes the signature information for the train approaching ABSU-1 24, and approaching train data field 36 includes the signature information for the train approaching ABSU-1 22. It should be noted that the use of a data field to store the signature of the train approaching an ABSU location is disclosed for the purpose of describing the preferred embodiment and is not intended to limit the invention hereto. Another, design choice is for each ABSU to include a second stack that stores the number and signatures of trains approaching the ABSU location (i.e. operating within the absolute block in the approach to the ABSU location). During the standby mode of operation, an ABSU displays a permissive signal indication, and the associated automatic train stop is in the clear position. Further, the ABSU performs three (3) main tasks or functions: First, the ABSU detects the crossing of the train approaching its location. The ABSU uses its axle counter and tag reader to verify that the train identified by the train signature stored in its approaching train data field has completely crossed its location. Upon such verification, the ABSU places the train signature at the bottom of its protected train stack. Second, the ABSU sends a message to the Approach ABSU to indicate that a specific train (as defined by a train signature) has crossed its location. Third, upon receiving a message from the ABSU Ahead that the train at the top of its protected stack has crossed the location of the ABSU Ahead, it removes that train from the stack, and sends a message to the ABSU Ahead to provide the signature of the next train in the stack that will be approaching the location of the ABSU Ahead. In the event, the protected stack is empty, then the ABSU sends a message to the ABSU Ahead indicating that no train is approaching its location.
(29) The ABSU active mode of operation is triggered when the associated CBTC system experiences a failure. During the active mode, and if the protected stack of an ABSU includes any trains, then the ABSU displays a stop aspect, and the associated automatic train stop is set to the tripping position. The ABSU will continue to process the trains in the protected stack similar to the standby mode, and upon verifying that the stack is empty, and depending on operating conditions, it will issue a movement authority limit or a restricted speed for the approaching train to operate through the associated absolute permissive block. In that respect, the operating conditions depend on the nature of the CBTC failure. For example, a zone controller failure causes all trains within its span of control to stop, and then proceed at restricted speed under operating rules and procedures. In such a case, the train signatures will reflect the operation with speed restrictions. A second example, is a single CBTC train failure that results in that train operating at restricted speed under operating rules and procedures. Accordingly, when describing the operation of the ABSUs in active mode, it is necessary to identify the operational assumptions associated with the CBTC failure. It is also important to note that one of the main assumptions related to CBTC and AWS operations is that there is no common failure mode that causes simultaneous failures in both CBTC and AWS. For example, it assumed that a CBTC communication failure will not impact communications between the ABSUs.
(30) It should be noted that the block diagram of FIG. 1 and the above description of the ABSU architecture and functionalities are being set forth herein for the purpose of describing the preferred embodiment, and are not intended to limit the invention hereto. As would be understood by a person of ordinary skills in the art, and as disclosed in the Summary Section of the invention, an alternate ABSU design can be used to implement the main functions of the invention. Pursuant to such alternate design, it is not necessary to provide a transponder reader, a wayside signal and an automatic train stop at each ABSU location. The function of communicating the train ID to the ABSUs can be provided by the on-board data radio. Further, an ABSU can perform all its monitoring functions in the “standby” operating mode without the need for a wayside signal and associated automatic train stop. In addition, during the “active” operating mode, an ABSU can generate and transmit a MAL to an approaching train without the need for said wayside signal and associated automatic train stop.
(31) FIGS. 3-18 demonstrate the operation of ABSU-1 26, ABSU-2 24 and ABSU-3 22 during a zone controller failure. As shown in FIG. 3, and upon a zone controller failure 61, all trains T-9 52, T-7 54, T-2 56, T-1 58 & T-11 59 within the span of control of the zone controller 30 will operate with a restricted speed 62. It is assumed that these trains have not experienced a failure, remain localized (i.e. can determine their own locations), and can communicate via radio communication. Also upon the zone controller failure 61, the ABSUs 22, 24 & 26 will switch to the active state. As such, ABSU-1 26 will display a stop aspect, and its associated automatic train stop will be in the tripping position. This is because the protected stack 42 of ABSU-1 26 includes three trains. Similarly, ABSU-2 24 will display a stop aspect, and its associated automatic train stop will be in the tripping position. This is because the protected stack 44 of ABSU-2 24 includes one train. With respect to ABSU-3 22, it will display a permissive aspect, and its automatic train stop will be in the clear position because its protected stack 46 is empty. As shown in FIG. 4, ABSU-3 22 issues a movement authority limit 64 to train T-11 59 to authorize it to proceed to the end of its associated absolute permissive block. Train T-11 59 can then operate to the end of its MAL 64 with normal operating speed, using onboard intelligence and complying with civil speed limits as provided by the onboard vital data base. It should be noted that in the event train T-11 59 does not establish radio communication with ABSU-3 22, then, the MAL 64 will be relayed to train T-11 59 via the active transponder associated with ABSU-3 22. Further, if train T-11 59 becomes delocalized, or if it exhibits a CBTC failure, then it can continue to move with restricted speed pursuant to operating rules and procedures.
(32) FIG. 5 reflects the movement of train T-11 59 past the location of ABSU-3 22. Upon a completion of this move, ABSU-3 22 displays a stop aspect, and controls its automatic train stop to the tripping position. Further, ABSU-3 22 sends a message to ABSU-2 24 indicating that train T-11 59 crossed its location. In turn, ABSU-2 24 displays a permissive aspect, and controls its automatic train stop to the clear position. ABSU-2 24 will then issue a movement authority limit 66 to approaching train T-1 58. This movement authority limit 66 authorizes train T-1 58 to move up to the location of ABSU-3 22.
(33) FIG. 6 reflects the movement of train T-1 58 passed the location of ABSU-2 24. Upon a completion of this move, ABSU-2 24 displays a stop aspect, and controls its automatic train stop to the tripping position. Further, ABSU-2 24 sends a message to ABSU-1 26 indicating that train T-1 58 crossed its location. In addition, ABSU-2 24 sends a message to ABSU-3 22 indicating that train T-1 58 is approaching the location of ABSU-3 22.
(34) FIG. 7 reflects the movement of train T-11 59 out of the absolute permissive block associated with ABSU-3 22. Also, it indicates that ABSU-1 26 has sent a message to ABSU-2 24, indicating that train T-2 56 is approaching the location of ABSU-2 24. Then FIG. 8 reflects the operation of ABSU-3 22 following the movement of train T-11 out of its absolute permissive block. ABSU-3 22 is indicated to display a permissive aspect, and its automatic train stop is in the clear position. Also, ABSU-3 22 is communicating a movement authority limit to train T-1 58 to proceed through its associated absolute permissive block.
(35) FIG. 9 reflects the movement of train T-1 58 past the location of ABSU-3 22, the permissive state of ABSU-2 24, and the communication of a MAL 70 to train T-2 56. This figure also shows the communications 72 & 74 between the various ABSUs. Similarly, FIG. 10 reflects the movement of train T-2 56 past the location of ABSU-2 24, and the communications 76 & 78 between the various ABSUs. FIGS. 11 & 12 show additional communications 80 & 82 between the ABSUs, as well as the communication of a MAL 84 to train T-2 56.
(36) FIG. 13 reflects the movement of train T-2 56 past ABSU-3 22, and shows the communications 86 & 88 from ABSU-3 22 to adjacent ABSUs. Then FIG. 14 shows the communication of a MAL 92 to train T-7 54. Similarly, FIG. 15 reflects the movement of train T-7 56 past ABSU-2 24, and shows the communications 90 & 92 from ABSU-2 24 to adjacent ABSUs. Then FIG. 16 shows the communication of a MAL 94 to train T-9 52. Also, FIG. 17 reflects the movement of train T-9 52 past ABSU-1 26, and shows the communications 96 & 98 from ABSU-1 26 to adjacent ABSUs. FIG. 18, the last figure in this operating scenario of a zone controller failure 61, shows communication 100 to ABSU-1 26 that train T-19 is approaching. The operation of the AWS will continue until the zone controller operates properly.
(37) A second AWS operating scenario is related to a failure of a single CBTC train, and is demonstrated in FIGS. 19-33. These figures show the operation of ABSU-1 26, ABSU-2 24 and ABSU-3 22 as the failed CBTC train moves through the territory. FIG. 19 indicate the operating conditions prior to the failure, wherein zone controller 30, and CBTC equipped trains T-9 52, T-7 54, T-2 56, T-1 58 & T-11 59 operate normally. Then FIG. 20 indicates that train T-2 56 has failed, and that upon such failure train T-2 56 is able to move with CBTC default restricted speed 108. Also, upon the failure of train T-2 56, the zone controller 30 informs 110 ABSU-1 26 of the failure. FIG. 21 indicates that the MALs for trains T-9 52, T-1 58 & T-11 59 are updated. However, the MAL 112 for train T-7 54 cannot be updated since failed train T-2 56 is not reporting its current location. Train T-2 56 continues to move with speed restriction.
(38) FIG. 22 reflects the movement of train T-1 58 past ABSU-2 24, and the movement of train T-11 59 past ABSU-3 22. Then in FIG. 23 and upon receiving a message that train T-1 58 has crossed ABSU-2 24, ABSU-1 26 sends a message 114 to ABSU-2 24 indicating that failed train T-2 56 is approaching its location. Then upon receiving this message 114, ABSU-2 24 displays a stop aspect and controls its automatic train stop to the tripping position.
(39) FIG. 24 indicates that trains T-7 54 and T-9 52 have reached the limits of their movement authorities, and are not able to move forward until receiving new movement authorities. FIG. 25 reflects the movement of train T-1 58 past ABSU-3 22. FIG. 26 indicates that upon receiving a communication from ABSU-3 22 that train T-1 58 has crossed its location 116, ABSU-2 24 displays a permissive aspect to train T-2 56. This enables failed train T-2 56 to proceed with restricted speed through absolute permissive block 23. It should be noted that it is a design choice to enable failed train T-2 56 to proceed with a higher restricted speed through absolute permissive block 23. In such case, the maximum operating speed within absolute permissive block 23 would be limited to smallest civil speed limit within this absolute block. The higher restricted speed is transmitted to failed train T-2 56 via the active transponder associated with ABSU-2 24. Alternatively, failed train T-2 56 can continue to move with the default CBTC restricted speed.
(40) FIG. 27 reflects the movement of failed train T-2 56 past ABSU-2 24, and the communications from ABSU-2 24 to ABSU-3 22 (that failed train T-2 is approaching its location 118), to ABSU-1 26 (that train T-2 has crossed its location 120), and to the zone controller 30 (that train T-2 has crossed its location 122). Upon receiving the communication that failed train T-2 56 is approaching its location, ABSU-3 22 displays a stop aspect, and controls its automatic train stop to the tripping position. Then in FIG. 28, and upon receiving the communication that failed train T-2 56 has crossed the location of ABSU-2 24, the zone controller 30 communicates 124 a movement authority limit 126 to train T-7 54 authorizing it to move to the ABSU-2 24 location.
(41) FIG. 29 reflects the movement of train T-7 54, and the communication 126 of a MAL from the zone controller 30 to train T-9 52. FIG. 30 shows the communication 128 to ABSU-3 22 that train T-1 has crossed the ABSU Ahead. Then FIG. 31 shows ABSU-3 22 displaying a permissive signal to enable failed train T-2 56 to proceed with a restricted speed.
(42) FIG. 32 reflects the movement of failed train T-2 56 past ABSU-3 22, and the communications from ABSU-3 22 to the ABSU Ahead (that failed train T-2 is approaching its location 130), to ABSU-2 24 (that train T-2 has crossed its location 132), and to the zone controller 30 (that train T-2 has crossed its location 134). Then in FIG. 33, and upon receiving the communication that failed train T-2 56 has crossed the location of ABSU-3 22, the zone controller 30 communicates 136 a movement authority limit 126 to train T-7 54 extending its MAL 138 to the ABSU-3 22 location. The operation of the AWS in conjunction with the zone controller 30 will continue until failed train T-2 56 is taken out of service or is repaired. It should be noted that it is a design choice as to how a movement authority is communicated from an ABSU to an approaching train. One design choice is to relay the movement authority via the zone controller. A second design choice is to send it directly from the ABSU to the train, and inform the zone controller.
(43) FIG. 34 shows the general approach to implement the ABSU concept at an interlocking 150 in accordance with the preferred embodiment. As indicated in the Summary Section of the invention, the ABSU functions are implemented as part of the interlocking control logic. Further, since the interlocking spans a plurality of approaches on a number of tracks, it needs to interface with each adjacent ABSU. As such, the ABSU at the interlocking (ABSU-IXL) 152 interfaces with the ABSUs in the approach to the interlocking 170 & 174 as well as the ABSUs ahead of the interlocking 176 & 172, wherein the terms “in the approach to,” and “ahead of” are based on traffic direction. Therefore, the specific interface functions between the ABSU-IXL 152 and an adjacent ABSU on a specific track depends on the traffic direction on that track. FIG. 34 shows an interlocking configuration 150 for a two track railroad, wherein track 1 (TK1) 175 designates one track, and track2 (TK2) 177 designates the second track. The interlocking includes two cross overs 165 & 167 with four track switches 3A, 3B, 5A and 5B. The “A” switches are associated with TK1 175, while the “B” switches are associated with TK2 177. The interlocking also includes four (4) home signals S2 158, S4 160, S6 164 & S8 162.
(44) For the preferred embodiment, ABSU-IXL 152 is designed to support bi-directional traffic on both TK1 175 and TK2 177. As such, each signal location (S2, S4, S6 and S8) includes an axle counter, a transponder reader and an active transponder 154, 155, 156 & 157. Further, the interlocking control module includes four data fields to store the signatures of trains approaching signal locations S-2 180, S4 182, S-6 184 and S-8 186. In addition, the interlocking control module includes four (4) protected stacks 190, 192, 194 and 196 (one protected stack for each destination ABSU 170, 172, 174 and 176). Further, the interlocking control module includes internal tracking stacks 200 to track train movements within the interlocking limits. As such, for the preferred embodiment, the train tracking stacks include TS-3A 202, TS-5A 206, TS-3B 204 & TS-5B 208. The communications between ABSU-IXL 152 and adjacent ABSUs 170, 172, 174 & 176 is provided by the Data Communication Network 20 that provides communications between the zone controller 30 and CBTC equipped trains 171.
(45) FIGS. 35 & 36 show the ABSU-IXL logical modules that are functioning for various traffic patterns. In FIG. 35, the traffic on TK1 222 is set to a Northern direction, and the traffic on TK2 220 is set to a Southern direction. For this traffic pattern, and assuming that all switches at the interlocking are in the normal position, the ABSU-DCL track 1 functioning configuration includes the Approach Train Data Field S-2 180, and the Protected Stack for track TK1 194. Similarly, the ABSU-IXL track 2 functioning configuration includes the Approach Train Data Field S-8 186, and the Protected Stack for track TK2 192. As such, for track TK1 175, the ABSU-IXL 152 communicates 230 with its Approach ABSU (ABSU-1 170), and also communicates 232 with the ABSU Ahead (ABSU-3 176). Further, with respect to track TK2 177, the ABSU-DCL 152 communicates 236 with its Approach ABSU (ABSU-4 174), and also communicates 234 with the ABSU Ahead (ABSU-2 172).
(46) Alternatively, in FIG. 36, the traffic on TK1 226 is set to a Southern direction, and the traffic on TK2 224 is set to a Northern direction. For this traffic pattern, and assuming that all switches at the interlocking are in the normal position, the ABSU-DCL track 1 functioning configuration includes the Approach Train Data Field S-6 184, and the Protected Stack for track TK1 190. Similarly, the ABSU-IXL track 2 functioning configuration includes the Approach Train Data Field S-4 182, and the Protected Stack for track TK2 196. As such, for track TK1 175, the ABSU-IXL 152 communicates 232 with its Approach ABSU (ABSU-3 176), and also communicates 230 with the ABSU Ahead (ABSU-1 170). Further, with respect to track TK2 177, the ABSU-IXL 152 communicates 234 with its Approach ABSU (ABSU-2 172), and also communicates 236 with the ABSU Ahead (ABSU-4 174).
(47) At a high level within the AWS system, the external operation and functions provided of the ABSU-IXL are similar to the operation and functions provided by any other ABSU. This means that the internal functions of the ABSU-IXL associated with routes within the interlocking, and tracking of trains and their signatures along those routes, are transparent to the AWS. FIGS. 37-43 demonstrate the standby mode operation of the ABSU-IXL 152 for a series of train moves. In this example the traffic direction for both TK1 175 and TK2 177 are set to a southern direction. FIG. 38 shows switch SW-3 167 in the reverse position, and signal S-2 158 cleared for train T-9 210 to proceed from track 1 to track 2. For this operating scenario, the Approaching Train Data Field S2 180 includes train T-9 210. Also, all the internal train tracking stacks 202, 204, 206 & 208 within the ABSU-IXL 152 are empty. Further, the protected stack on TK2 196 includes train T-19 214. In addition, the Approaching Train Data Field S-4 182 reflects train T-11 212.
(48) FIG. 38 reflects the movement of train T-9 210 past home signal S-2 158. As a result, Approaching Train Data Field S-2 180 is set to “E” (empty), and internal train tracking stack TS-3A 202 registers the signature for train T-9 210. Then FIG. 39 reflects further movement of train T-9 210 over switch S-3 167 and past the track circuit boundary 211 within the detector circuit for switch S-3. This will cause internal train tracking stack TS-3B 208 to register the signature of train T-9 210.
(49) FIG. 40 reflects the movement of train T-9 210 past signal S-8 162. As a result, the internal train tracking stacks TS-3A 202 and TS-3B 208 are set to “E” (empty), and the protected stack for TK2 196 reflects two train signatures for T-19 214 and T-9 210. Then FIG. 41 reflects the establishment of a route within the interlocking for train T-11 212 to move past signal S-4 160 over switch S-3 167 normal.
(50) FIG. 42 reflects the movement of train T-11 212 past signal S-4 160. As a result, the internal train tracking stacks TS-5B 204 and TS-3B 208 register the signature of train T-11 212, and Approaching Train Data Field S-4 182 is set to “E” (empty). Then in FIG. 43, train T-11 212 leaves the interlocking passed signal S-8 162. This result in the clearing of the internal train tracking stacks TS-5B 204 and TS-3B 208. Further, the protected stack for TK2 196 reflects the signature of train T-11 212.
(51) FIGS. 44-55 demonstrate the active operation of the ABSU-IXL 152, during a zone controller 30 failure, and for the same series of train moves indicated in FIGS. 37-43. FIG. 44 shows the operating conditions before the zone controller 30 failure. Then in FIG. 45, upon the failure 220 of the zone controller 30, trains T-2 216, T-9 210, T-19 214 and T-11 212 lose their movement authorities and operate under a speed restriction 221. Based on initial traffic conditions, ABSU-1 170, ABSU-2 172 and ABSU-4 174 display a stop aspect, while ABSU-3 176 displays a clear aspect. Also, the interlocking protected stack for TK1 194 includes train T-2 216, and the interlocking protected stack for TK2 196 includes train T-19 214. Further, the Approaching Train Data Field S-2 180 includes train T-9 210, and the Approaching Train Data Field S-4 182 includes train T-11 212.
(52) FIG. 46 reflects the transmission of a movement authority limit 218 from ABSU-3 176 to train T-2 216. Then, FIG. 47 indicates the movement of train T-2 216 past ABSU-3 176, and the transmission of a movement authority limit 222 from ABSU-4 174 to train T-19 214 upon the clearing of the absolute permissive block protected by ABSU-4 174.
(53) FIG. 48 reflects the movement of train T-19 past ABSU-4 174, the clearing of signal S-2 158, and the transmission of a movement authority limit 224 from ABSU-IXL 152 to train T-9 210 over switch SW-3 167 reverse. Then FIG. 49 reflects the movement of train T-9 224 past signal S-2 158 and the tracking of train T-9 210 by the internal tracking stack TS-3A 202. This figure also shows the permissive state for ABSU-1 170 to permit a following rain to move closer to the interlocking.
(54) FIG. 50 reflects the movement of train T-9 210 and the interlocking tracking of that train by internal tracking stack TS-3B 208. Then FIG. 51 reflects the movement of train T-9 210 past signal S-8 162 and the clearing of the internal tracking stacks TS-3A 202 and TS-3B 208. Further, the interlocking protected stack for TK2 196 includes train T-9 210.
(55) FIG. 52 shows that upon the clearing of ABSU-4 174, the movement authority limit 224 for train T-9 210 is extended past ABSU-4. Then FIG. 53 reflects the movement of train T-9 210 past ABSU-4 174, the resulting clearing of the interlocking protected stack for TK2 196, the subsequent clearing of signal S-4 160, and the transmission of a movement authority limit from ABSU-IXL 152 to train T-11 212 to proceed past signal S-4 160 over switch SW-3 167 normal.
(56) FIG. 54 reflects the movement of train T-11 212 into the interlocking past signal S-4 160, and the tracking of train T-11 212 by internal tracking stacks TS-5B 204 and TS-3B 208. Then FIG. 55 reflects the movement of train T-11 212 past signal S-8 162, the clearing of the interlocking internal tracking stacks TS-5B 204 and TS-3B 208, and the status of the interlocking protected stack for TK2 196 that now includes train T-11 212.
(57) It should be noted that the demonstrations shown in FIGS. 37-55 are set forth herein for the purpose of describing the preferred embodiment and are not intended to limit the invention hereto. As would be understood by a person with ordinary skills in the art, a different architecture to track trains within the interlocking limits could be devised. For example, a different design choice is to provide an internal tracking stack for each internal interlocking route, and to select the appropriate stack based on switch positions. It should also be noted that the proper tracking of trains within an interlocking is based on the established premise that switches are locked by a switch detector circuit, and cannot change position as long as the detector circuit is occupied by a train.
(58) FIGS. 56-61 demonstrate the process to initialize a failed zone controller using data from the ABSUs. FIG. 56 shows the initial operating conditions prior to the restoration and initialization of the failed zone controller 30, wherein the AWS in the zone controller territory includes ABSU-1 26, ABSU-2 24 and ABSU-3 22, and wherein five (5) trains operate in the territory. This figure shows the initial conditions for the ABSUs, wherein ABSU-1 26 and ABSU-2 24 are displaying a stop aspect, while ABSU-3 22 is displaying a “clear” aspect. The figure also shows trains T-1 58, T-2 56, T-7 54 and T-9 52 operating with a speed restriction 62, while train T-11 59 is operating with a movement authority limit 237.
(59) FIG. 57 indicates that upon the restoration of the zone controller 30, it establishes communications 240, 242 and 244 with ABSU-1 26, ABSU-2 24 and ABSU-3 22. Then upon the establishment of such communications, each ABSU communicates the sequence of trains (i.e. relative train positions) within its protected stack 42, 44 & 46, as well as the signatures of these trains. As such, ABSU-1 26 communicates to the zone controller 30 the signatures for trains T-1 58, T-2 56 and T-7 54. Similarly, ABSU-2 24 communicates to the zone controller 30 the signature for train T-11 59. Also, ABSU-3 22 communicates to the zone controller 30 that its absolute block territory has no trains. The signature for train T-9 52 is provided to the zone controller 30 by the ABSU in the approach to ABSU-1 26.
(60) FIG. 58 shows that upon receiving train signature information from the various ABSUs, the zone controller 30 establishes communications with each of the identified trains. As such the zone controller establishes communications 241, 243, 245, 247 & 249 with trains T-9 52, T-7 54, T-2 56, T-1 58 and T-11 59. Then FIG. 59 shows that, upon establishing communication with a train, the zone controller 30 receives the train's location and evaluates traffic conditions to determine if it can issue a movement authority to the train. More specifically, the zone controller employs the relative train positions received from the ABSU's to determine if a movement authority can be issued to a train. For example, if the zone controller 30 is evaluating traffic condition ahead of train T-7 54, it confirms that it has established communication with train T-2 56 and has received its current location before it issues a movement authority 250 to train T-7 54. Alternatively, if the zone controller 30 fails to establish communication with a train, it cannot issue a movement authority to a following train. For example, if the zone controller 30 fails to communicate with train T-2 56, then it cannot issue a movement authority to train T-7 54. In such a case, train T-7 54 will continue to operate with a restricted speed until the zone controller establishes communication with train T-2 56 and ascertains its location.
(61) As such, FIG. 59 reflects the condition that the zone controller 30 has established communications with all the identified trains. It should be noted that the movement authority issued to a train is limited by the location of a train ahead, or the location of an ABSU that is displaying a “stop” aspect. In this case, the movement authority for train T-9 52 is limited by the stop aspect of ABSU-1 26. Similarly, the movement authority for train T-1 58 is limited by the stop aspect of ABSU-2 24.
(62) Upon receiving communication from an approaching train that it was issued a movement authority by the zone controller, the associated ABSU displays a clear aspect, and switches its mode of operation to the “standby” mode. As such, FIG. 60 reflects the condition that both ABSU-1 26 and ABSU-2 24 have switched to the standby mode after receiving communications from approaching trains T-9 52 and T-1 58. Then FIG. 61 demonstrates that upon receiving communications from ABSU-1 26 and ABSU-2 24 that they have switched to the “standby” mode, the zone controller 30 extends the movement authorities 252 & 254 for trains T-9 52 and T-1 58 to the location of the train ahead. This concludes the initialization process for the zone controller 30.
(63) It should be noted that the zone controller initialization process demonstrated in FIGS. 56-62 is set forth herein for the purpose of describing the preferred embodiment, and is not intended to limit the invention hereto. As would be understood by a person with ordinary skills in the art, various changes in the disclosed process could be utilized to initialize the zone controller after a failure condition. For example, upon establishing communications with all identified trains and ascertaining their locations, the zone controller can communicate to the ABSUs to switch to the “standby” mode. It should also be noted that in the event a train fails to communicate with a zone controller, it will be continue to be tracked by the ABSUs as demonstrated in FIGS. 22-33.
(64) As indicated in the summary section herein, in the event an ABSU fails while it is operating in a standby mode, the CBTC system detects such failure, and removes the failed ABSU from the AWS configuration. FIG. 62 shows the traffic conditions prior to an ABSU failure, wherein CBTC operation is in progress and ABSU-1 26, ABSU-2 24 and ABSU-3 22 are operating in a “standby” mode. Under this operating scenario, protected stack 42 for ABSU-1 26 includes trains T-1, T-2 and T-7, while the protected stack 44 for ABSU-2 24 includes train T-11. Then FIG. 63 indicates that ABSU-2 24 has failed 256. The zone controller 30 detects this failure either through a loss of communication 242 with ABSU-2 24, or by receiving an error message from ABSU-2 24. FIG. 64 demonstrates that upon detecting a failure in ABSU-2 24, the zone controller 30 communicates the failure condition 240 & 244 to ABSU-1 26 and ABSU-3 22, and augments the protected stack 42 of ABSU-1 by adding train T-11. In effect, the protected stack 44 of the failed ABSU-2 24 is combined with the protected stack 42 of ABSU-1 26, which is the “Approach ABSU” to the failed ABSU-2. This ABSU reconfiguration results in a longer absolute permissive block 258 that combines the territories of the two permissive absolute blocks in the approach to and ahead of failed ABSU-2 24. Also, upon receiving communication from the zone controller that ABSU-2 24 has failed, ABSU-1 26 and ABSU-3 22 establish communication together as adjacent ABSUs. Further, as shown in FIG. 65, since train operation is under CBTC protection and because the ABSUs do not provide any train protection while operating in the “standby” mode, ABSU-2 24 is designed to fail into an overridden failure state, wherein a special override aspect is displayed and the automatic train stop is set to a clear position. It should be noted that this reconfiguration process is transparent to, and has no impact on CBTC operation. It should be noted that the use of zone controller to manage the failure of an ABSU that is operating in the “standby” mode is set forth herein for the purpose of describing the preferred embodiment and is not intended to limit the invention hereto. As would be appreciated by a person of ordinary skills in the art, the management of the ABSU failure could be achieved without the zone controller. For example, and as disclosed in the summary section herein, and upon a failure of an ABSU, the Approach ABSU and the ABSU ahead can establish communication together and form a longer absolute permissive block to reconfigure the AWS system around the failed ABSU. The Approach ABSU will use “provisional” trains as place holders during a transition period until the AWS system operates normally with the longer absolute permissive block. Since the ABSUs are operating in the “standby” mode, CBTC train service is not affected.
(65) An alternate ABSU failure scenario can occur when the ABSUs are operating in the active mode. In such scenario, the zone controller is not available to affect the reconfiguration of the ABSUs during an ABSU failure. It should be noted that an ABSU failure while operating in the active mode constitutes a double failure (since the ABSU would fail at the same time when the zone controller has also failed), which is very unlikely. It should also be noted that an ABSU failure while operating in active mode would involve multiple operating scenarios related to the operating condition of the train approaching the failed ABSU. For example, an approaching train could be operating with a movement authority limit, operating with a restricted speed, or could be operating manually pursuant to operating rules and procedures. As disclosed above, a data field within the train signature reflects the operating condition of the train (train status). In view of such multiple operating scenarios, the preferred embodiment provides a unique design for the ABSU that controls the failure state of the ABSU if the failure occurs during an active mode operation. This design is related to the aspect that is displayed at the failed ABSU and the status of the automatic train stop.
(66) More specifically, and as shown in FIG. 65, during an active mode of operation, an ABSU is designed to fail in one of two failure states depending on the operating condition of the approaching train. The first failure state is defined as the “override” failure state, and is selected if the train approaching the ABSU is an equipped train with a train signature that indicate that the train is equipped and is operating either with a MAL or a speed restriction. In the “override” state, the ABSU is designed to automatically display an “override” aspect and to drive the automatic stop to a clear position. Further, in the override mode, the active transponder defaults to transmitting a special failure code to an approaching train. This special failure code is ignored under most operating conditions, except when an approaching train has neither a MAL that ends at the failed ABSU location. In such case, the detection of the special failure code authorizes the train to proceed at a restricted speed. The second failure state is identified as “stop” failure state, and is selected if the train approaching the ABSU does not have a train signature or has a train signature that does not reflect a valid train status (in such a case the approaching train is considered unequipped). In the “stop” state, the ABSU is designed to automatically display a “stop” aspect and to drive the automatic stop to a tripping position.
(67) Under normal AWS operating conditions, an equipped train (with a proper train status reflected in its signature) approaching an ABSU is operating under the protection of either a MAL or a restricted speed. Alternatively, a train without a signature or without a proper train status is considered to be a manual train with no speed restrictions. Accordingly, the failure recovery process when an ABSU that fails while operating in the active mode is as follows: Upon the occurrence of an ABSU failure, it is assumed that communication is interrupted between the failed ABSU and the Approach ABSU, as well as with the ABSU Ahead. In accordance with the preferred embodiment, the ABSU is designed to establish communication with the next ABSU in an AWS configuration when communication is lost with an adjacent ABSU. As such, when an ABSU fails, the Approach ABSU and the ABSU ahead establish communication together as adjacent ABSUs. After such communication is established, the Approach ABSU receives from the ABSU Ahead the train signature of the train approaching its location. Then upon receiving such train signature, the Approach ABSU places the received train signature at the top of its protected stack. However, since the Approach ABSU has no current information related to the trains that were included in the protected stack of the failed ABSU, it inserts additional “provisional” train signatures between the train signature received from the ABSU Ahead and the train signature that was originally at the top of its protected stack. The number of provisional train signatures is a design choice, and is resolved when the train that was originally at the top of said protected stack reaches the ABSU Ahead.
(68) An example of the above disclosed process is provided in FIG. 66, wherein ABSU-2 24 fails 259 while operating in the active mode. In this operating scenario, the protected stack 44 for ABSU-2 24 includes two trains: T-1 58 and T-5 101. The approaching train to ABSU-3 22 is T-1 58, and the train at the top of the protected stack for ABSU-1 26 is T-2 56. As such, train T-5 101 is not identified to both ABSU-1 26 and ABSU-3 22.
(69) FIG. 67 reflects the expanded protected area 260 for ABSU-1 26, as well as the expanded protected stack 42 for ABSU-1 26 that shows train T-1 58 at the top of the stack, and provisional trains P-1 through P-n between T-1 and train T-2 56. Then FIGS. 68 & 69 reflect the movement of train T-1 58 past ABSU-3 22, the temporary identification of the approaching train to ABSU-3 as P-1, and the detection of train T-5 101 by ABSU-3 (either through radio communication or via the transponder reader for ABSU-3). Train T-5 101 will be processed normally by ABSU-3 22, and will be given a MAL upon the clearing of the protected area of ABSU-3 22.
(70) FIGS. 70 & 71 reflect the movement of train T-5 101 past ABSU-3 22, the temporary identification of the approaching train to ABSU-3 as P-2, and the detection of train T-2 56 by ABSU-3 (either through radio communication or via the transponder reader for ABSU-3). Upon the detection of train T-2 56 at ABSU-3 22, and upon communicating this detection to ABSU-1 26, ABSU-1 clears the remaining provisional train signatures from its protected stack 42.
(71) With respect to the failure mode of ABSU-2 24, and because prior to its failure it received data that approaching train T-2 56 is an equipped train with proper status, ABSU-2 has failed in the “override” failure state. This means that train T-2 56 will receive a default code as it reaches the location of ABSU-2, and will continue to operate with speed restriction until it reaches ABSU-3 22. With respect to train T-7 54, it will also continue to operate with speed restriction past ABSU-2 24 until it reaches ABSU-3 22. In effect, the above described failure management process enables the AWS to “self-heal” from the ABSU-2 failure by combining the absolute permissive blocks of ABSU-1 26 and ABSU-2 24 into a longer absolute permissive block.
(72) It should be noted that the premise of selecting an ABSU failure mode based on the operating condition of the approaching train, and without consideration of the operating conditions of trains following the approaching train within the same absolute permissive block, is based on the assumption that the zone controller and the AWS will not permit a manual train (i.e. without speed restriction) to operate following another train within an absolute permissive block. It should also be noted that if a train without a manual train was approaching ABSU-2 prior to its failure, then ABSU-2 will fail in the “stop” failure state. In such case, ABSU-2 24 will require a manual override to permit the train to proceed to ABSU-3.
(73) In general, the AWS system can be designed to provide protection to manual trains that operate within the AWS territory without speed restrictions. This requires each ABSU to provide an overlap past its location to account for the breaking distance for the manual train tripping at the ABSU location at maximum attainable speed. To implement such design without adding more wayside equipment, and to maintain the generic approach for the ABSU design, the overlap distance is provided by a second absolute permissive block. This means that for a manual train to proceed past an ABSU, the protected stack of two consecutive ABSUs must be empty. As such, the operation of a manual train without speed restriction is demonstrated in FIGS. 72-74. It should be noted that to ensure safety of operation, the minimum length of an absolute permissive block must be greater that the longest braking distance based on maximum attainable speed.
(74) FIG. 72 shows a manual train M-1 265 approaching ABSU-1 26. The recognition of a manual train is based on the design assumption that a manual train does not have a proper train status. However, a manual train is still being tracked by the AWS using the number of axles in the train. Upon the detection that M-1 265 is approaching its location, and despite the operating condition that its protected stack has no trains, ABSU-1 26 displays a stop aspect, and its automatic train stop is in the tripping position. ABSU-1 26 requests 270 ABSU-2 24 to reserve its absolute permissive block as an overlap distance for M-1 265. In effect, for this operating scenario, ABSU-1 protects 42 the required overlap (“O-1”) for M-1 265, and O-1 is considered an approach to 34 ABSU-2 24.
(75) FIG. 73 reflects the crossing of train T-11 59 past ABSU-3 22, and the availability of an overlap block 23 for train M-1 265. ABSU-2 24 communicates 272 this availability to ABSU-1 26. In turn, ABSU-1 26 displays a clear aspect and controls its automatic train stop to the clear position. Then FIG. 74 shows the movement of train M-1 265 past ABSU-1 26, the communication 274 from ABSU-1 to ABSU-2 24 that M-1 265 is approaching the ABSU-2 location, and the communication 276 from ABSU-2 to ABSU-3 22 to reserve an overlap distance to M-1 265. For this operating condition, the protected stack 42 for ABSU-1 and the approaching train data field 34 for ABSU-2 reflect train M-1. Also, the protected stack 44 for ABSU-2 and the approaching train data field 36 for ABSU-3 reflect overlap requirement O-1. This ABSU operation continues as described to control the movement of a manual train throughout the AWS territory. Although the disclosure of the AWS architecture presented herein is focused on providing a train control installation as a backup to a CBTC system, the proposed train control architecture can be used as a primary train control system on a line, or a section of a line, that does not require high throughput. Since the proposed architecture provides a distance-to-go operation compatible with CBTC, it could be installed on a branch line that feeds a high capacity corridor equipped with CBTC.
(76) As would be understood by those skilled in the art, alternate embodiments could be provided to implement an auxiliary train control system based on the absolute permissive block concept, and using the new concepts described herein. For example, each ABSU can communicate all the signatures data of the trains within its protected stack to the ABSU Ahead. This will simplify the AWS reconfiguration process in the event of an ABSU failure. Further, the overlap function could be provided via the installation of an auxiliary set of axle counter ahead of the ABSU location to ensure that sufficient braking distance is provided at each ABSU for the operation of a manual train. It is also to be understood that the foregoing detailed description of the preferred embodiment has been given for clearness of understanding only, and is intended to be exemplary of the invention while not limiting the invention to the exact embodiments shown.
(77) Also, it should be noted that the ABSU and the interlocking control device can utilize alternate vital programs to implement the described train control functions. Obviously these programs will vary from one another in some degree. However, it is well within the skill of the signal engineer to provide particular programs for implementing vital algorithms to achieve the functions described herein. In addition, it is to be understood that the foregoing detailed description has been given for clearness of understanding only, and is intended to be exemplary of the invention while not limiting the invention to the exact embodiment shown. Obviously certain subsets, modifications, simplifications, variations and improvements will occur to those skilled in the art upon reading the foregoing. It is, therefore, to be understood that all such modifications, simplifications, variations and improvements have been deleted herein for the sake of conciseness and readability, but are properly within the scope and spirit of the following claims.
