Patent ID: 12187330

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention describes a new structure, and/or a new method to implement an Autonomous Train Control System (ATCS). This new structure is based on the concept of a plurality of autonomous train control elements that operate independent of each other, and interface with each other for the purpose of relinquishing and/or acquiring “track space.” The ATCS normally controls train movements within a section of a railroad or within a transit line. Similar to other train control systems, an ATCS installation covers a plurality of tracks, as well as track switches that provide means for trains to move from one track to another. The “track space” is defined as the longitudinal stretch along the entire physical track installed within the ATCS territory, and including the track within interlockings. For the preferred embodiment, the track space within the ATCS territory is allocated to the various autonomous train control elements, which include physical trains, interlocking elements, absolute block signal units (optional), grade crossings, and any other train control element that requires an allocation of track space. An additional class of autonomous train control elements is used in the preferred embodiment to represent free, un-occupied, or un-allocated track space. This additional class is defined as “virtual trains.” Each of the autonomous train control elements operate pursuant to a set of rules. Further, each class of autonomous train control elements is assigned a priority level with respect to the acquisition or relinquishment of track space. An element with a higher priority level, can acquire allocated track space from another element with lower priority level.

The use of virtual trains to represent free track space requires the introduction of a secondary concept related to the acquisition and relinquishing of track space. Since a virtual train does not represent, or correspond to a physical train entity, certain physical train functions are not suitable to be performed by a virtual train. For example, a virtual train should not activate grade crossing protection as it moves in the approach to and through a grade crossing territory. However, there is still a need for a virtual train to operate and move through grade crossing territory. Similarly, some interlocking functions require the acquisition of track space held by a grade crossing element. For example, when performing traffic reversal between interlockings the track space allocated to a grade crossing element must be assigned to interlocking element. Such assignment must be performed without activating the grade crossing element. As such, the preferred embodiment employs the concept of “leasing” and “vacating” track space. By leasing track space assigned to a grade crossing control element, a virtual train can proceed through the grade crossing track section without activating the crossing. Similarly, by leasing track space from a grade crossing element, an interlocking element can reverse traffic without activating the grade crossing. It should be noted that although a grade crossing element leases track space to a virtual train or an interlocking element, the track space remains assigned to the grade crossing element. As such leased rack space must be returned to the grade crossing element when it is vacated and cannot be transferred directly to another element. For example, a virtual train that vacates a track space leased from a grade crossing element returns the vacated track space back to the grade crossing element for releasing to a following virtual train, or to be relinquished to a following physical train.

The interfaces between autonomous train control elements are identified based on relative geographic locations, and include the communication pairing of adjacent elements for the purpose of acquiring/relinquishing track space, as well as exchanging operational data. The preferred embodiment includes two additional elements: The first element is defined as Track Space Controller (TSC), and its main functions include the implementation and management of virtual trains, as well as to facilitate the interfaces between various autonomous train control elements. The second element is defined as a Communication Interface Controller (CIC), and its main function is to manage the communication pairing of autonomous train control elements.

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.1is a conceptual abstract diagram of the proposed ATCS, showing the track space10, and the various autonomous train control elements, including physical trains20, interlocking elements30, grade crossing elements40, virtual trains50, Absolute Block Signal Units (ABSU)60& any other train control element62. The initial allocation of track space to the train control elements is made during system and/or train initialization, and is based on predefined rules. With respect to fixed location train control elements, track space initial allocation is based on fixed geographical limits. For example, the initial track space allocated to an interlocking element30includes the switch detector area as well as the approaches to the interlocking. Similarly, the initial track space allocated to a grade crossing element40includes the track space along the grade crossing island as well as the approaches. ABSUs60receive an initial track space allocation that includes the associated absolute signal block. A virtual train50receives an initial track space allocation, or a leased track space allocation, upon the creation of the train based on predefined rules. Similarly, a physical train20receives an initial track space allocation upon the initialization of the train based on predefined rules. It should be noted that the initial allocation to ABSUs60is an interim allocation until the track space is reallocated to other train control elements during normal system operation.

The system initialization process, during which track space is initially allocated to train control elements, is based on an initial sweep of the track space sections to ensure that they are vacant. As a design choice, fixed block detection could also be used in certain track sections to ensure that no trains are present in these track sections. For example, fixed block detection could be used within switch detector areas and the island sections of grade crossings. Upon system and train initializations, and the establishment of normal operation, the train control elements relinquish and acquire70track space to paired element based on operating conditions and predefined set of rules. Virtual trains operating in the vicinity of grade crossing elements lease and vacate track space71based on operating conditions and predefined set of rules.

FIG.2shows a block diagram of a typical configuration for the proposed ATCS in accordance with the teachings of the preferred embodiment. This configuration includes physical trains T-1108and T-2112, virtual trains V-3136, V-6122& V-8128, interlocking element126, absolute block signal units ABSU2116& ABSU3117. The ATCS also includes centralized computing resources100, which includes two main elements: the Track Space Controller (TCS)120, and the Communication Interface Controller (CIC)110. The main functions performed by the TCS120include the implementation and management of virtual trains130&134, and the management of interfaces with physical elements124as well as interfaces with external systems134. The main function of the CIC110is to pair the autonomous train control elements together based on location and operational data received from the TCS120. As such, for the ATCS configuration shown inFIG.2, and for the relative positions of trains shown, virtual train V6122is paired140with physical train T-1108, virtual train V-8128is also paired142with T-1108. In turn, V-8128is also paired144with physical train T-2112and absolute block signal unit ABU2116. Further, physical train T-2112is paired146with interlocking element IXL-1126. In addition, virtual train V-3136is paired148with IXL-1126and ABSU3117. It should be noted that as the relative positions of trains change, the pairing of train control elements changes. This is a dynamic process based train locations and operational data.

As indicated above, physical trains acquire and relinquish track space from/to other train control elements. More specifically, and as shown inFIG.3, a physical train150can acquire track space from another physical train152, a virtual train154, an interlocking control element156, a grade crossing control element157, or an absolute block signal unit (ABSU)158. The acquisition of track space takes place as a train ahead (physical152or virtual154) vacates track space, in response to a route request to an interlocking control element156, in response to a request for track space to a grade crossing control element157, or during a failure condition, wherein an ABSU158relinquishes the track space associated with its absolute signal block (ASB) after ensuring that the ASB is vacant. It should be noted that to proceed through a grade crossing section, it is necessary for the physical train to acquire track space directly from the grade crossing. A train (physical or virtual) moving ahead of the physical train must relinquish/release vacated track space to the grade crossing element for reassignment to the following physical train.

Similarly, a physical train150can relinquish track space to another physical train160, a virtual train162, an interlocking control element164, a grade crossing control element166, or an absolute block signal unit (ABSU)168. The relinquishing of track space takes place after the physical train150vacates track space upon its movement in the indicated direction151.

FIGS.4&5show certain characteristics of the autonomous operation for physical trains. Each physical train control element establishes a movement authority limit (MAL) based on the available track space it has acquired from paired elements. Also, a physical train control element establishes a stopping profile that is based on the MAL. As disclosed above, to the extent possible, it is desirable to provide an “optimum” track space to a physical train in order for the physical train to operate at the maximum allowable operating speed within the territory. As such,FIG.4reflects an operating scenario, wherein the current track space and associated MAL170for a physical train is less than the required optimum track space172. Based on the premise that physical trains have an assigned level of track space acquisition priority that is higher than that of virtual trains, the autonomous operation of physical trains includes a feature wherein a physical train acquires more track space from a paired virtual train to satisfy its optimum track space requirements. As such, inFIG.4, physical train153requests track space from paired front virtual train176to satisfy the requirement for an optimized track space172. In the event the needed track space174is more that the track space175allocated to the virtual train176, the process is repeated until the optimized track space172is satisfied. Alternatively, if the needed track space174is less than the track space175allocated to the virtual train176, then the virtual train176will relinquish the needed track space174to the physical train153. However, if the remaining track space for the virtual train176is less than a certain threshold, the entire track space175assigned to the virtual train176is relinquished to the physical train153. In such a case, the virtual train176is retired.

A second characteristic of the physical train autonomous operation is associated with the operating scenario depicted inFIG.5, wherein the track space180allocated to a physical train155exceeds a maximum track space threshold182. In the preferred embodiment, it is not desirable for a physical train to acquire track space way in excess of its optimum track space. As such, one autonomous operation characteristics of physical train is to relinquish track space when its allocated space exceeds a maximum threshold. An example of an operational scenario that results in excess track space186occurs when a physical train is delayed and keeps accumulating track space from a train ahead that is moving away from its location. InFIG.5, when the track space allocated to a physical train155exceeds the maximum track space threshold182, the physical train relinquishes the excess track space186for the creation or activation of a new virtual train181.

FIG.6shows another operating scenario, wherein a physical train relinquishes track space to a paired autonomous train control element. In the preferred embodiment, a physical train is requested to relinquish track space to a paired autonomous train control element that has a higher assigned level of track space acquisition priority. Upon receiving such request, the physical train relinquishes part or all of the requested track space provided that it does not violate safety rules. InFIG.6, interlocking element IXL-1188requests physical train T-5157to relinquish part of its track space190in order to process a higher priority move for physical train T-7159through the interlocking. As part of the physical train autonomous operation, physical train T-5157relinquishes the requested track space to IXL-1188only if it can stop using service brake prior to reaching the interlocking, within its truncated track space192. It should be noted that, under rare operating conditions, a physical train will truncate its movement authority without relinquishing any track space, and resulting in an emergency brake application in order to mitigate safety hazards. An example of such operating condition is an open switch point within the track space assigned to the physical train. An alternate design requires the allocated track space to be relinquished to the interlocking element in the event of an open switch point.

Another characteristic of physical train autonomous operation is related to failure conditions. One unique characteristic of the ATCS is the mechanism used to detect failures of physical trains and communicate failure information to other train control elements. A failure is detected by self-diagnostics of the failed physical train element or by loss of communication with a paired train control element. Failure information, including the identity and characteristics of the failed physical train are propagated within the ATCS using daisy chain communication by paired train control elements. The preferred embodiment identifies a physical train by a “train signature.”FIG.7shows various design options to provide physical train signature for a train consist161. A first design option is to define the train signature as the number of axles193in the train consist161. A second design option is to define the train signature as the combination of a fixed ID195embedded in a first passive transponder (tag)196, and the number of train axles193. The third design option is similar to the second option, wherein the train signature is a combination of a train ID and the number of axles. However, the train ID includes a fixed field based on information embedded in a transponder, and a variable field that reflects the route ID for the train197. The route ID changes for each train trip, but remains fixed during a train trip. In the preferred embodiment, a train trip is defined as the trip from an initiating terminal station to a destination terminal station. The fourth design option is to define the train signature as a combination of a first fixed train ID195, the number of axles193in the train consist, and a second fixed train ID199embedded in a second passive transponder194. It should be noted that additional train status information could be included in the train signature. For example, the train signature could reflect the train operating status, including if the train is operating with a restricted speed or based on a movement authority limit.

FIG.8demonstrates the concept of propagating physical train failure information by relaying the failure data from one train control element to the next. InFIG.8, physical train T-1200has experienced a failure and is unable to communicate with paired205virtual train204and paired203physical train202. Upon losing communication with T-1200, physical train T-2202transmits a “Trailing Train Failure” (“TTF”) message207to paired train control elements ABSU-3210and virtual train V-12208. The TTF message207identifies the failed physical train as T-1200, using its train signature. Upon the movement of physical train T-2202past ABSU-3210, ABSU-3 is preconditioned to detect the crossing of T-1200. Further, as physical train T-2202continues to move, it will propagate the T-1200failure data to paired fixed location train control elements.

Similarly, upon losing communication with T-1200, virtual train V-8204transmits a “Leading Train Failure” (“LTF”) message209to paired train control elements ABSU-2212and virtual train V-6206. The LTF message209identifies the failed physical train as T-1200, using its train signature. Upon receiving the LTF message209, ABSU-2212requests V-8204to relinquish its entire track space. In addition, ABSU-2212requests V-6206to relinquish part of its track space that falls within the absolute signal block211. The track space controller will then retire virtual train V-8, and ABSU-2212switches to the active mode to control the movement of trains into its associated absolute signal block. Upon receiving confirmation from ABSU-3210that failed train T-1200has passed its location, ABSU2212will switch to a permissive state and will relinquish its entire track space (equal to the absolute signal block) to an approaching train. It should be noted that with respect to virtual train V-6206, it will relay the LTF message to an approaching train, and will most likely relinquish its remaining track space to the approaching train.

Although physical trains have a high level of priority with respect to the acquisition of track space, this high priority level is reduced in the event of a failure or a loss of communication. The movement of a failed physical train and the recovery of the ATCS from such failure are described as part of the ABSU autonomous operation.

Virtual trains are logical elements that represent free/unassigned track space, but have a similar operational behavior to physical trains. These logical elements are implemented as part of the TSC and operate autonomously based on predefined rules.FIG.9shows the interactions between a virtual train220and other train control elements. A virtual train220can acquire track space from a physical train222, another virtual train224, an interlocking control element228, or an absolute block signal unit (ABSU)226. In addition, virtual train220can lease space from a grade crossing element230. The acquisition of track space takes place as a train ahead (physical222or virtual224) vacates track space, in response to a route request to an interlocking control element228, or during a failure condition, wherein an ABSU226relinquishes the track space associated with its absolute signal block (ASB) after ensuring that the ASB is vacant. Further, the virtual train220receives leased space in response to a request for track space to a grade crossing control element230.

In addition, a virtual train220can relinquish track space to a physical train232, another virtual train234, an interlocking control element238, or an absolute block signal unit (ABSU)236. Also, the virtual train220returns vacated space back to a grade crossing control element240. The relinquishing of track space takes place after the virtual train220vacates track space upon its movement in the indicated direction221.

FIG.10shows certain characteristics of the autonomous operation for virtual trains. Similar to physical trains, each virtual train establishes a movement authority limit (MAL) based on the available track space it has acquired from paired elements. Also, a virtual train establishes a stopping profile that is based on the MAL, as well as simulation engine parameters that provide operation of virtual trains based on line operating conditions. It should be noted that although a virtual train has a stopping profile associated with a MAL, such a stopping profile does not constrain certain autonomous functions for virtual trains. For example, if a virtual train needs to be retired, this function could be executed without a delay associated with stopping the virtual train. Referring toFIG.10, upon the creation of a virtual train245, it receives an initial track space allocation250, and the virtual train is then paired with adjacent train control elements to acquire/relinquish track space. As the virtual train245continues to operate on the line, its allocated track space varies. If the allocated track space falls below a minimum threshold252, the virtual train245is retired and its allocated track space is relinquished to a paired train control element. Conversely, if the allocated track space exceeds a maximum track space threshold254, the allocated track space is truncated to the initial track space250, and the excess track space256is used to create a new virtual train. These autonomous rules for the operation of a virtual train ensures that during service interruption affecting the movement of a physical train, there is a manageable track space assigned to the virtual train.

FIG.11shows examples of operating scenarios during which a virtual train258relinquishes a part or its entire allocated track space to another autonomous train control element. In the first example, virtual train258relinquishes track space259to physical train260during the initialization process of the physical train. In the second example, virtual train258relinquishes track space261to physical train260for the purpose of enabling physical train260to meet its optimum space requirements. In the third example, virtual train258relinquishes track space263to interlocking element262to enable interlocking operation (for example, the movement of a switch, or the establishment of a route). In the fourth example, virtual train258relinquishes track space265to an ABSU element264upon the detection of a physical train failure. It should be noted that additional rules for the autonomous operation of virtual trains may be required under unique operating conditions. Such rules will supplement the rules disclosed herein, and will be based on the premise that virtual trains have the lowest priority with respect to track space acquisition. It should also be noted that the concept of virtual trains provides a number of benefits to the ATCS, including flexibility of operation for autonomous train control architecture.

FIG.12shows characteristics of the autonomous operation of an interlocking element270for an operating traffic direction271. In general, an interlocking element acquires track space from a paired element when it is necessary to modify an existing route, establish a new route or modify traffic directions. There are a number of alternate design choices when routes are fleeted (same route is established for consecutive trains). In the first alternative, and pursuant to one design choice, a train moving away from the interlocking relinquishes vacated track space to a following train that is operating on the same route. In such a case, the interlocking element simply monitors the track space transaction between the two trains, and ensures that the route remains secured and locked. In the second alternative, a train moving away from the interlocking relinquishes vacated track space to the interlocking element for reassignment to a following train. As such,FIG.12shows various operating conditions during which the interlocking element270acquires track space from paired elements. The interlocking element270acquires vacated track space from physical train272and virtual train277as they move away from its location. Also, the interlocking element270acquires track space from a second interlocking element274, and leases track space from grade crossing element278for the purpose of changing a traffic direction. Further, the interlocking element270acquires track space from an ABSU276for the purpose of performing an interlocking function.

The interlocking element270also relinquishes track space285to paired elements under various operating conditions. For example, upon receiving a request for a route from an approaching physical train280, or an approaching virtual train286, the interlocking element270will establish and secure the requested route and will relinquish the associated track space to the train that has requested the route. Also the interlocking element270relinquishes track space to another interlocking element284to enable the modification of a traffic direction. Further, the interlocking element270relinquishes track space to an ABSU284to enable a failed train to operate in a section controlled by the ABSU284. In addition, the interlocking element270vacates track space287that was leased from a grade crossing element288after completing a traffic reversal operation. It should be noted that a physical train is not required to be paired to an interlocking element to request an interlocking route. The preferred embodiment employs a concept wherein an interlocking route request could be relayed to an interlocking element through a daisy chain configuration of virtual trains ahead of its location.

FIGS.13&14show the configuration of the various routes at a typical diamond crossover interlocking for the preferred embodiment. In general, there are three route sections for each interlocking route: an “approach” section “R1NA”300, “R2NA”302, “R1SA”304& “R2SA”306, a “switch” section “R1NN”301, “R1NR”303, “R2NN”305, “R2NR”307, “R1SN”309, “R1SR”311, “R2SN”313& “R2SR”315, and an “exit” section “R1NX”310, “R2NX”312, “R1SX”314& “R2SX”316.

FIG.15explains the designation of the route sections for the preferred embodiment. The left most letter “R”320is the designation for “Route.” The second letter322designates the track where the route initiated. In this case, the designation is “1” for TK1 or “2” for TK2. The third letter324designates direction of travel: “N” for North and “S” for South. The fourth (right most) letter326designates the function of route section, i.e. “A” for an approach section, “N” for a switch section in the Normal position, “R” for a switch section in the Reverse position, and “X” for an exit route section. It should be noted that this designation is provided for the purpose of demonstrating the preferred embodiment and is not intended to limit the invention hereto. As would be understood by a person skilled in the art, different route designations could be used. For example, a designation based on switch number could be used.

With respect to the interaction between a train290approaching an interlocking element291, the train290requests track space associated with a route to reach a destination track. For example, inFIG.14train290moving South on track TK2 requests the interlocking element291to relinquish track space to reach destination track TK1. In such case, the interlocking element291establishes and secures a route that includes the route sections “R2SA”306, “R2SR”315and “R1SX”314. The interlocking element291will then relinquish the track space associated with the route sections to train290. In effect, the interlocking element291is paired with approaching train290, and as such it has the origination point for the route. Upon receiving the destination point, it is able to establish and secure the requested route.

FIG.16demonstrates the concept of advanced route setting, wherein physical train330relays its request for a route to TK2336to paired virtual train332. In turn, virtual train332will request the interlocking element334to establish a route to track TK2336. Upon receiving this request from virtual train332, the interlocking element334establishes the requested route for both the virtual train332and the physical train330.

FIG.17demonstrates one of the autonomous functions performed by an interlocking element344related to the creation of a virtual train346under certain operating conditions. In this operational scenario, physical train340is moving over an interlocking route from track TK1 to track TK2. During the operation of physical train T-3340, the interlocking element acquires vacated track space from virtual train V-9342, which is moving away from the interlocking. Since no train is able to follow virtual train V-9342while the physical train340movement is in progress, the interlocking element will continue to acquire more track space343. When the acquired track space exceeds a maximum threshold343, the interlocking element creates a new virtual train V-5346that is assigned the excess track space347. This process continues until a train is able to make a normal move over the interlocking.

FIG.18demonstrates another autonomous function performed by the interlocking element related to the traffic reversal process. In the shown example, Traffic362is set to a Northern direction. The traffic reversal process starts by a request from physical train T5358to interlocking element IXL-2356to establish a route from track TK2 to track TK1. To implement the requested route, IXL-2356requires the reversal of traffic direction362. Interlocking element IXL-2356initiates a request for traffic reversal to IXL-1352. To implement the traffic reversal function, IXL-1352needs to acquire the entire track space364between IXL-1352and IXL-2356on TK1. As such, IXL-1352continues to acquire vacated track space366from physical train354. Upon the acquisition of the entire track space364between the two interlockings, IXL-1352relinquishes the entire track space364to IXL-2356. In turn, IXL-2356reverses traffic direction362and establishes the requested route for physical train T5356.

FIG.19demonstrates an alternative configuration of autonomous train control elements, and an associated process for traffic reversal. Similar to the operational scenario ofFIG.18, physical train T5358requests interlocking element IXL-2356to establish a route from track TK2 to track TK1. This requires that the direction of traffic362be reversed to a Southern direction. As explained above, interlocking element IXL-2356initiates a request for traffic reversal to DM-1352. To implement the traffic reversal function, IXL-1352needs to acquire the entire track space364between IXL-1352and IXL-2356on TK1. In this case, the track space364between IXL-1 and IXL-2 includes track space that is allocated to virtual train V-9372, virtual train V-7374and grade crossing370. In view of the premise that virtual trains have the lowest priority with respect to track acquisition, upon receiving a request from interlocking element IXL-1352, virtual trains V-9372and V-7374relinquish their entire allocated track space to IXL-1352. Virtual trains V-9 and V-7 are then retired. With respect to the track space376allocated to grade crossing370, it cannot be relinquished to IXL-1352, as such transfer of track space will result in the activation of the grade crossing370, which is operationally undesirable. However, as explained above, the preferred embodiment includes the premise of leasing the track space allocated to the grade crossing to an interlocking element for the purpose of enabling traffic reversal. As such, upon receiving a request from IXL-1352, grade crossing370leases its allocated track space376to IXL-1. The interlocking element IXL-1352then transfers the entire track space364to IXL-2356. This will enable IXL-2 to reverse traffic direction and establishes the route requested by physical train T-5358. Upon the completion of the traffic reversal, interlocking element IXL-2356releases track space376back to the grade crossing element370.

FIG.20demonstrates the autonomous functions performed by an interlocking element IXL-2355upon completing a traffic reversal function. The first action performed by IXL-2355is to release track space376to grade crossing element370. IXL-2355relinquishes track space to physical train358as part of the established route from track TK2 to track TK1. IXL-2358also relinquishes the remaining traffic track space364to a newly created virtual train V-5379. It should be noted that the initial assignment of track space associated with traffic to the physical train358and the newly created virtual train379is performed without consideration of the track space rules associated with the autonomous operation of physical trains and virtual trains. These rules become effective after such initial assignment, and may result in the creation of additional virtual trains.

FIG.21shows characteristics of the autonomous operation of a grade crossing control element400for an operating traffic direction401. In general, a grade crossing control element maintains track space that enables vehicle traffic to proceed on the intersecting roadway. It communicates with traffic signal controller to provide advance notification of an approaching physical train, and receive status information related to traffic signal operating and health conditions. The grade crossing element400relinquishes its track space only after ensuring that the traffic signal controller is operating correctly, that all minimum functional timing requirements for traffic signals and any associated pedestrian signals have been complied with, and that its warning signals and gates have been activated. As such, grade crossing element400relinquishes track space403to an approaching physical train402or to an absolute block signal unit404in the event of a failure condition. The grade crossing element leases track space407(without affecting road traffic operation) to virtual trains406and interlocking elements408.

Upon the movement of a physical train410past its location or the completion of manual train operation under the supervision of an ABSU412, the grade crossing element400acquires the associated track space405before notifying the traffic signal controller to resume road traffic. Similarly, a virtual train414or an interlocking element416will release track space409back to the grade crossing element400either after the completion of the virtual train movement, or the completion of the interlocking function requiring the leased track space.

FIG.22demonstrates interactions between the grade crossing control element430and other autonomous train control elements. The grade crossing element430controls the warning lights and gates440at the intersecting roadway438. In general, the grade crossing element holds track space associated with grade crossing islands444for TK1 and TK2. The grade crossing islands444correspond to the intersections between railroad tracks TK1 & TK2 and the roadway438protected by the grade crossing element. Further, the grade crossing element430controls track space in the approach to island sections440on both tracks from both the North and South directions442. There are two main trigger mechanisms for the grade crossing element430. The first trigger is based on normal operation, wherein a physical train420activates the crossing as it moves within a predetermined distance from the intersection. The second trigger occurs during a physical train failure condition, wherein the operation of the failed physical train426is under the control of ABSUs432&434.

Under normal train operation, the grade crossing element430must provide adequate warning time to pedestrian and vehicle traffic when a physical train approaches the intersection. With respect to operation on TK1 ofFIG.22, virtual trains V-7422and V-9424traverse through the grade crossing boundaries (track space associated with approaches and island) without activating the grade crossing equipment. This is based on the above described concept of leased track space. Virtual train V-9422is paired with following physical train T-1420, and as such it informs the grade crossing controller430that physical train T-1420is approaching. Upon receiving such notification, the grade crossing controller430monitors the position of virtual train V-9422, and when the virtual train V-9422is at the boundary of its southern approach, it acquires the entire track space leased to virtual train V-9422and effect the retirement of this virtual train. This will result in the pairing of grade crossing controller430with approaching physical train T-1420. When physical train T-1420reaches a predefined location from the grade crossing island, the grade crossing controller430will execute a process to communicate with traffic light signal controller, and activate the grade crossing equipment440. After receiving confirmation that the grade crossing equipment440has been activated, the grade crossing controller430relinquishes track space to the physical train T-1420to proceed through the grade crossing territory. It should be noted that the location of physical train T-1420at which the grade crossing controller430starts to execute the grade crossing activation process can vary based on the speed of the approaching physical train T-1420. In order to ensure adequate warning time at the grade crossing, the grade crossing controller430transmits to approaching physical train T1420a minimum time duration before physical train T-1 can enter the island track space. When physical train T-1420vacates the island track space444, the grade crossing controller430commences a process to deactivate the grade crossing equipment440.

With respect to the operation on track T-2 ofFIG.22, failed physical train T-5426is held at ABSU3434, until the absolute block track space436associated with ABSU3434is free of physical trains. Upon acquiring the entire absolute block track space436, including leased track space442&444from the grade crossing controller430, ABSU3434requests the grade crossing controller430to acquire the leased track space associated with the grade crossing442&444in order to enable failed physical train T-5426to proceed through the absolute block territory436. Upon receiving such request, the grade crossing controller430executes the grade crossing activation process and upon receiving confirmation that the grade crossing equipment440has been activated, it enables failed physical train T-5426to proceed through the absolute block track space436. Then upon receiving confirmation from ABSU5432that failed physical train T-5426has crossed its location, the grade crossing controller starts the process to deactivate the grade crossing equipment440. It should be noted that under this operation scenario, the activation time for grade crossing equipment could be long. One design choice is to use auxiliary detection at the crossing island444to shorten the activation time by deactivating the crossing equipment440after the failed physical train T-5426leaves the crossing island444.

As explained above, the grade crossing element430normally holds the track space at the intersection islands444, and controls the track space442in the approach to intersections. This enables the grade crossing element430to allow vehicle traffic on the roadway438when there are no physical trains approaching the intersection, or in the event of an operational scenario that requires a physical train to move close to the intersection without actually crossing the intersecting roadway. One such operating scenario is shown inFIG.23, wherein physical train T-1420makes a station stop and then turns back over an interlocking switch447without reaching the intersection island track space444. The grade crossing controller430relinquishes only the approach track space442to physical train T-1420upon receiving a stop assurance that the physical train will stop before reaching the grade crossing island444. A stop assurance function is generated by the physical train420, and indicates that the train is able to stop within its allocated track space that was relinquished to the train by the grade crossing controller430.

As explained above, the ATCS includes an optional autonomous train control element, which is defined as an Absolute Block Signal Unit (ABSU), to provide a backup mode of operation during system failures. Further, the ABSU facilitates system and train initializations. The ABSU operation is based on the absolute permissive block principle, wherein a train is given a movement authority to proceed through a block from the entering boundary of the block to its exit boundary when the entire block is vacant. The design of the ABSU is based on a generic configuration of traditional signal elements. As shown inFIG.24, a typical ABSU500includes a processing module512, a communication module502, an axle counter506, a transponder antenna508, an optional active transponder510and an optional signal/stop element514.

FIG.25shows characteristics of the autonomous operation of an Absolute Block Signal Unit (ABSU)515for an operating traffic direction520. In general, an ABSU element acquires track space from a paired element when it is necessary to provide a backup mode of operation during system failures. As such,FIG.25shows various operating conditions during which the ABSU element515acquires track space from paired elements. The ABSU element515acquires vacated track space from physical train532during a failure condition. This ABSU function is triggered upon the detection of a failed physical train approaching its location. Similarly, when operationally required, the ABSU element515acquires track space from a virtual train534during a failure condition. The acquisition of track space from a virtual train534is not based on vacated track space, but rather an ABSU element acquires the entire track space assigned to a virtual train, and which falls within the ABSU territory. Further, an ABSU element515acquires track space within its associated absolute block territory from an interlocking element536. In such a case, the ABSU element515also ensures that an interlocking route is secured for the movement of a failed physical train through its absolute block territory. Similarly, an ABSU element leases/acquires track space from a grade crossing element528that is located within its absolute block territory.

Normal ATCS operation does not require an ABSU element515to acquire track space from an ABSU ahead540. However, under unique operating condition, wherein it is desirable to operate a manual train, an ABSU element acquires track space from an ABSU ahead to provide an overlap (sufficient breaking distance) for manual train operation.

The ABSU element515does not directly relinquish track space to a failed physical train since the failed physical train may not be paired with the ABSU element. Rather, the ABSU515permits the failed physical train to proceed through its track space until it leaves its absolute block territory. Further, upon receiving confirmation from the ABSU ahead that the failed physical train has passed its location, the ABSU element515relinquishes its track space to an approaching physical train522. Similarly, an ABSU element515relinquishes its track space to a new created virtual train524upon the completion of a failed physical train movement outside of its absolute block territory. In addition, an ABSU element515relinquishes track space to an interlocking element526to enable the execution of interlocking functions. Also, the ABSU element515relinquishes space to a grade crossing element528as demonstrated inFIG.22. Furthermore, the ABSU515relinquishes track space to an approach ABSU530to support manual train operation as explained above.

FIG.26demonstrates the basic autonomous operation of an ABSU element. As explained above, during normal ATCS operation, the ABSU elements operate in a passive mode to monitor the operation of autonomous trains (physical and virtual), without performing any control function that affects train movements. Upon the detection of failed physical train T-7542that is approaching its location, ABSU-5543switches to an active mode of operation wherein it controls the movement of trains into its associated absolute block track space548. ABSU-5543acquires track space550that is vacated by a physical train T-5544, which is moving away from its location. Then upon acquiring the entire absolute block track space550, ABSU-5543permits failed train T-5544to move past its location and enter its associated absolute block territory550. Depending on the type of failure, ABSU-5543can transmit a movement authority limit to failed train T-5544using an active transponder510(FIG.24). Alternatively, ABSU-5543can activate a permissive wayside signal to authorize failed train T-5543to operate manually past its location.

FIG.27illustrates certain ABSU autonomous functions associated with a physical train T-5553failure. In this figure, physical trains T-3555, T-5553and T-7551are operating in the vicinity of ABSU-3559and ABSU-5551. Prior to the failure, the physical trains had track space allocations552,554&556as shown inFIG.27. Upon the failure of physical train T-5553, and especially if physical train T-5 is not able to communicate with paired train control elements T-3555and T-7551, physical train T-5553cannot relinquish vacated track space to T-7551, and cannot acquire additional track space from T-3555. As such, failed physical train T-5553initially retains the track space it had554at the time of the failure. The movement of T-5 is then governed by operating rules and procedures. Typically in the preferred embodiment, T-5 receives authorization to proceed at restricted speed passed the limit of its allocated track space554. Further, physical train T-7551is not able to acquire additional track space, and as such is not able to move past the movement authority limit associated with its track space552. In addition, track space vacated by T-3555cannot be assigned to T-5.

Upon losing contact with failed physical T-5, physical train T-3555informs ABSU-3559that a failed physical train is approaching its location. It also provides ABSU-3 with the train signature information for failed train T-5. This enables ABSU-3 to identify physical train T-5 when it approaches its location. It also enables ABSU-3 to determine when all the axles of T-5 have passed its location. Further, upon receiving T-5 failure information, ABSU-3559switches to the active mode. Then upon the movement of physical train T-3555past its location, ABSU-3559assumes the “stop” operating state and acquires the track space vacated by T-3 in the approach to its location. ABSU-3 then holds said vacated track space in abeyance to be relinquished to the next train T-7551at a later time. In addition, ABSU-3 starts acquiring the additional track space vacated by T-3555. Then, upon accumulating track space equal to its associated absolute block track space, ABSU-3559authorizes failed physical train T-5553to pass its location as explained by the operation shown inFIG.26. Also, after the movement of T-5 past the location of ABSU-3559, ABSU-3 creates a new virtual train and relinquishes the track space that was originally assigned to T-5 together with the track space held in abeyance560to the new virtual train. The newly created virtual train will operate within the track space occupied by T-5, and will relinquish vacated track space to physical train T-7551.

In addition to providing a fallback mode of operation during ATCS failures, ABSUs are used to support system and train initialization functions. Upon entering a territory controlled by the Autonomous Train Control System (ATCS), a physical train is initialized to operate in the territory. The physical train initialization process consists of a number of functions, including localization of the physical train, sweeping track space adjacent to the front and back ends of the train (also known as the “sieving function”), establishing communication with the Track Space Controller (TSC), transmitting physical train operating data to the TSC, allocating an initial track space to the physical train, and pairing the physical train with appropriate autonomous train control elements. To establish initial communication with the TSC, the CIC includes a number of memory pairing modules defined as “incubators,” and are used to establish communication between a newly initialized physical train and the TSC. In order to control the initialization process, ABSUs operate in the active mode, wherein they control movement of localized and paired trains into the associated absolute block track space territories. Under the active mode, an ABSU accumulates track space from a paired physical train that is localized. Further, an ABSU receives the sieving status of the localized train moving away from its location, and uses this status as one of the parameters to determine if an approaching physical train should be authorized to move into its associated absolute block track space.

An illustration of the sweeping process is shown inFIG.28, wherein a localized physical train T-5563is sieved at the location of ABSU-7565. The sieving process ensures that there is no short train hidden in front or in the back of the physical train563. As such, the sieving process is performed in two steps. In the first step, the front of physical train T-5563is sieved when T-5 reaches the location of ABSU-7 while the absolute block track space564in its entirety is assigned to ABSU-7565(i.e. free of physical trains). Alternatively, the front of T-5 is sieved when it reaches the location of ABSU-7 while ABSU-7 holds part of its associated absolute block track space564. Similarly, in the second step, the rear end of physical train T-5563is sieved when all the axles of T-5 pass the location of ABSU-7565while the absolute block track space562in its entirety is assigned to ABSU-5561(i.e. free of physical trains). To implement this sieving process, it is necessary for ABSU-3566, ABSU-5561and ABSU-7565to exchange operational data. It is also necessary to establish communication between ABSU-7565and T-5563to confirm to T-5 that the sieving process was completed successfully. Further, during the implementation of a sieving process, it is necessary for the ABSUs to coordinate their activities and ensure that train movements do not interfere with the sieving process. For example, ABSU-5561prevents trains from entering its associated absolute block track space562while the sieving process for T-5563is on-going. Similarly, ABSU-7565prevents T-5 from entering its associated absolute bock track space564until it verifies that at least the near end part of this track space is vacant. This will ensure the successful sieving of T-57563.

It should be noted that additional autonomous train control elements could be implemented in an ATCS system. For example, an autonomous train control element could be defined and implemented to establish a work zone and to authorize the movement of trains within its boundaries. Since work zones could be implemented at any location on the track, they are classified as a temporary autonomous train control element. In the preferred embodiment, a work zone element is created by the Track Space Controller (TSC) and is allocated an initial track space. Upon its creation, the work zone train control element can create virtual trains to operate within its allocated track space. The work zone element can also relinquish track space to other train control elements, including an approaching physical train, based on predefined rules. A physical train operating within the territory assigned to a work zone element must operate at a reduced speed that is established by the work zone element and communicated to the physical train. In the preferred embodiment, track space that is located within a work zone and vacated by a physical train is relinquished back to the work zone element for reassignment to a virtual train or a following physical train. When the work zone is no longer needed and upon receiving confirmation from a supervisory control system, the TSC will retire the work zone element. The track space assigned to the work zone element will then be reassigned to virtual trains and/or to an approaching physical train as the case may be.

One element of the ATCS is defined as the Track Space Controller (TSC). The TCS manages the interfaces between the various autonomous train control elements, as well as the interfaces between the ATCS elements and other systems in the ATCS operating environment. In addition the TCS manages the creation and retirement of virtual trains and work zone elements. The TCS can be implemented on a dedicated centralized computing environment, or in a network computing environment such as cloud, distributed or virtual network computing. The general architecture of the TCS is demonstrated by the block diagram shown inFIG.29.

The TCS599includes a physical interface module602to interface the various TCS elements with physical elements, including physical trains612, interlocking control elements616, grade crossing control elements614and Absolute Block Signal Units (ABSU)618. A data communication network600is used to interconnect the TCS599with the autonomous physical elements. In addition, the TCS599includes a diversity of logical and memory modules. Logical modules634&636are used to provide computing resources for virtual trains, while memory modules626,628,630&638are used to store operational data related to autonomous physical elements.

In the preferred embodiment, the operation of the TCS is controlled by the train controller module604, which also controls the creation/activation and retirement of virtual trains. To that extent, an address bus608and a data bus632are used to enable the train controller module604to control the operation of the various modules included in the TCS599. It should be noted that, and as would be understood by a person skilled in the art, a separate TCS processor could be used to control the operation of the TCS. In such an embodiment, the function of the train controller module604is limited to the creation/activation and retirement of virtual trains. Upon receiving a request from an autonomous train control element to create or activate a new virtual train, the train controller604selects and activates a “spare” logical element634to provide the computing resources for the newly created virtual train. The train controller604assigns a unique train ID to the newly created virtual train, as well as an initial location that must be confirmed with the autonomous train control element that requested the creation of the new virtual train. Further, the train controller604communicates with the Communication Interface Controller CIC610via the CIC Interface620requesting that the newly created virtual train be paired with the autonomous train control element that requested the creation of the virtual train. In turn, the paired autonomous train control element confirms the location of the new virtual train and relinquishes track space to it.

Alternatively, under certain operating conditions, an autonomous train control element requests the retirement of a virtual train. An example of such operating conditions is during the initialization of a physical train. Typically for the preferred embodiment, a physical train is initialized as a replacement of an existing virtual train, and by acquiring its allocated track space. The virtual train is then switched to a standby mode or state (“standby mode”), its logical element is spared, and the physical train receives an initial movement authority limit associated with the retired virtual train. This movement authority limit is adjusted to account for the length of the physical train. In general, upon receiving a request from an autonomous train control element to retire a virtual train, the train controller604acknowledges the request and informs the train control element of a “pending” status of the request. The train control element then acquires the track space assigned to the virtual train, and confirms to the train controller604that the virtual train is ready to be retired. Upon receiving such confirmation, the train controller604retires the virtual train and assigns a “spare” status to the corresponding logical module634.

The TSC599further includes a Simulation Engine Module624that provides nominal operating speeds for the various virtual trains operating in the ATCS territory. The nominal operating speeds are based on the average operating speeds of physical trains612operating at various sections of the ATCS territory, as well as civil speed limits. It should be noted that physical trains612provide operational data (location, speed, etc.) to corresponding memory modules638that reside in the TSC599.

At the time of a physical train initialization, the train controller604assigns a memory module to it. Similarly, each autonomous train control element614,616&618is assigned an associated memory module625,628&630within the TSC599. The memory modules stores real time data related to the operational statuses of the corresponding autonomous train control elements, and provide relevant data to the CIC610. The real time data includes operational and maintenance data and are used to provide train location and status information for the Automatic Train Supervision displays as well as for maintenance functions.

In addition, the TSC599includes two memory modules that provide line data necessary for the operation of the autonomous train control elements. The line data memory unit622stores track geometry information including data for grades, curves, super elevation, station platforms, civil speed limits, locations of wayside equipment, etc. Similarly, interlocking data memory unit626stores data related to interlocking configuration, route and traffic patterns, track switch information, etc. In the preferred embodiment, the line data is downloaded from the Automatic Train Supervision (ATS) system via the ATS interface module606. In turn, relevant line data is downloaded to physical trains612at the time they are initialized in ATCS operation. In addition the ATS system provides itinerary data for each physical train to control and regulate its movement through the ATCS territory. The train itinerary data includes train destination, identity of interlocking routes, required station stops, schedule data, etc. In addition, the ATS system can issue direct commands to physical trains that impact normal scheduled operation. These commands include skip station stop, hold train at station, emergency stop, change itinerary, etc. Further, the ATS system provides line/train regulation data that is sent in the form of performance parameters to physical trains. It should be noted that one design choice is to store the physical train612itinerary data, any direct ATS commands and regulation data in the corresponding memory modules638. In addition, and as disclosed above, operational parameters of virtual trains could be used for the purpose of train regulation.

The physical interface unit602provides the needed wireless communications, via wireless communication network600, between trackside physical elements612,614,616&618and corresponding logical/memory modules638,625,628&630. It should be noted that communications between paired and interconnected physical elements do not go through the physical interface602. However, communications between paired physical elements and virtual trains pass through the physical interface unit602.

Another element of the ATCS is defined as the Communication Interface Controller (CIC). The CIC's main function is to dynamically manage in real time the pairing of various ATCS elements. In general, the CIC receives location information from the Track Space Controller (TSC), and assigns communication frequencies/channels to paired ATCS elements. Further, in the preferred embodiment, the CIC provides fixed communication links/channels between fixed location ATCS elements. The general CIC architecture proposed for the preferred embodiment is shown inFIG.31.

The CIC610includes a CIC processor650that control the operation of the CIC unit, a plurality of pairing memory modules652,654,656,658,660,668,670,672&674, a data bus662, an address bus664, and an interface to the data communication system600. The main function of a pairing memory module is to store in real time the identity information of the ATCS elements paired together, as well as data related to the communication frequencies/channels used for the paired communications. To that extent, and to facilitate the implementation of the pairing process, the preferred embodiment employs an architecture that includes different types of modules. There are modules that include two cells652,656,658&660, which are used for the pairing of two ATCS elements. Further, there are modules that include three cells654,668,670,672&674, which are used for the pairing of three ATCS elements. In general, a three-cell module is used to pair a fixed element (IXL616, XING614& ABSU618) with physical and/or virtual trains. Also, certain two-cell modules660are used to pair or provide communication links between fixed location elements. Other two-cell modules656are used to pair moving ATCS elements. Spare modules658are provided to accommodate increased traffic conditions. In addition, a number of cells652are dedicated for incubator functions to establish initial communication between newly initialized physical trains and the TSC599.

It should be noted that the preferred embodiment employs cell designations to facilitate the dynamic pairing of ATCS elements. For example, the designations “F” for fixed location, “C” for physical train and “I” for incubator are designed to establish communication for physical elements through the Data Communication Network. Similarly, the designations “V” for virtual train and “t” for Track space controller are designed to establish communication to modules within the TSC. The “s” designation is for spare cells. Preferably, the pairing memory modules could be configured geographically during the application design along individual tracks. It should also be noted that the above CIC architecture is being disclosed for the description of the preferred embodiment. As would be understood by persons skilled in the art, different architectures could be devised to provide the functions for the CIC element. For, example network communication switching could be used to provide the interconnections (pairing) for the various ATCS elements. In addition, pairing memory modules capable of pairing more than three elements could be provided if required by the track configuration warrants it.

As would be understood by those skilled in the art, alternate embodiments could be provided to implement an Autonomous Train Control System based on the new concepts disclosed herein. For example, and as disclosed in the detailed description of an alternate embodiment, physical elements, including physical trains, interlocking control devices, grade crossing control devices and ABSUs could be virtualized and implemented in a network computing environment.

DETAILED DESCRIPTION OF AN ALTERNATE EMBODIMENT

Referring now to the drawings where the illustrations are for the purpose of describing an alternate embodiment of the invention and are not intended to limit the invention hereto,FIG.32shows a block diagram of a configuration of the proposed Autonomous Train Control System (ATCS) in accordance with the teachings of the alternate embodiment. This configuration includes physical trains T-1710and T-2112, virtual trains V-3742, V-6746& V-8744, interlocking element706, absolute block signal units ABSU2709& ABSU3707. The ATCS also includes centralized computing resources760that is implemented in a cloud computing environment, and which includes two main elements: the Track Space Controller (TCS)700, and the Communication Interface Controller (CIC)750.

The TCS700includes logical modules that provide virtualization of physical train control elements. More specifically, the TCS700includes logical modules that are defined as “Avatar” trains A-1745& A-2743, and which correspond to physical trains T-1710and T-2712. Also, the TCS700includes a logical module VIXL-1730that virtualizes the interlocking control unit714. In addition, the TCS700includes logical modules VABSU-2732and VABSU-3728that virtualize Absolute Block Signal Units ABSU-2709and ABSU-3707. It should be noted that if the physical train control installation includes a grade crossing control device, then the ATCS will also include a virtual grade crossing control element that performs the required grade crossing functions in the context of an Autonomous Train Control System.

In the alternate embodiment, the main functions performed by the TCS700include the management of virtual trains742,744&746, the management of logical modules that provide virtual train control elements that correspond to physical elements, management of interfaces716and communications between virtual train control elements and corresponding physical elements, and the management of interfaces with external systems720. In effect, the main concept used in the alternate embodiment is for the virtual train control elements (avatar trains, virtual trains, virtual interlocking control elements, virtual Absolute Block Signal Units, and virtual grade crossing control units) to operate autonomously from each other, exchange virtual track space that corresponds to the physical track space within the ATCS territory, receive status information from corresponding physical elements and transmit control data to corresponding physical elements.

Similar to the preferred embodiment, the main function of the CIC750is to pair the virtual train control elements together based on location and operational data received from the TCS700. As such, for the ATCS configuration shown inFIG.32, and for the relative positions of trains shown, virtual train V6724is paired with avatar train A-1745, virtual train V-8744is also paired with A-1745. In turn, V-8744is also paired with avatar train A-2743and virtual absolute block signal unit VABU-2732. Further, avatar train A-2743is paired with virtual interlocking control element VIXL-1730. In addition, virtual train V-3742is paired with VIXL-1730and ABSU3728. It should be noted that avatar trains A-1 and A-2 continuously reflect the movements of associated physical trains T-1 and T-2. It should also be noted that as the relative positions of avatar (physical) trains and virtual trains change, the pairing of train control elements change. This is a dynamic process based train locations and operational data.

Referring now toFIG.33, where the illustrations are for the purpose of describing the alternate embodiment of the invention and are not intended to limit the invention hereto,FIG.33is a conceptual diagram of the proposed ATCS, showing virtual track space800, and the various autonomous virtual train control elements, including avatar trains802, virtual interlocking control elements803, virtual grade crossing control elements804, virtual trains805, virtual Absolute Block Signal Units (ABSU)806& any other virtual train control element811. The virtual track space800corresponds to the track space within the ATCS territory. Similar to the preferred embodiment, the main concept for the operation of the alternate embodiment is for the various virtual train control elements to acquire virtual track space, then operate autonomously within that space in accordance with predefined rules. As part of normal ATCS operation, virtual train control elements exchange virtual track space807with paired elements. Similar to the preferred embodiment, the initial allocation of virtual track space809to the virtual train control elements is made during system and/or train initialization, and is based on predefined rules.

With respect to the autonomous operation of an avatar train, it is similar to the operation of the physical train described in the preferred embodiment. As such, an avatar train acquires and relinquishes virtual track space from/to other virtual train control elements. More specifically, and as shown inFIG.34, an avatar train821can acquire track space from another avatar train820, a virtual train822, a virtual interlocking control element824, a virtual grade crossing control element826, or a virtual absolute block signal unit (ABSU)828. The acquisition of virtual track space takes place as a train ahead (avatar820or virtual822) vacates virtual track space, in response to a route request to a virtual interlocking control element824, in response to a request for virtual track space to a virtual grade crossing control element826, or during a failure condition, wherein a virtual ABSU828relinquishes the virtual track space associated with its absolute signal block (ASB) after ensuring that the ASB is vacant. It should be noted that to proceed through a grade crossing section, it is necessary for the avatar train to acquire track space directly from the grade crossing. A train (avatar or virtual) moving ahead of the avatar train must relinquish/release vacated virtual track space to the virtual grade crossing element for reassignment to the following avatar train.

Similarly, an avatar train821can relinquish virtual track space to another avatar train830, a virtual train832, a virtual interlocking control element834a virtual grade crossing control element836, or a virtual absolute block signal unit (ABSU)838. The relinquishing of virtual track space takes place after avatar train821vacates virtual track space upon its movement in the indicated direction825.

FIGS.35&36show certain characteristics of the autonomous operation for avatar trains. Each avatar train establishes a movement authority limit (MAL) based on the available virtual track space it has acquired from paired elements. The MAL is then transmitted to the associated physical train. In turn, the physical train establishes a stopping profile that is based on the MAL received from the avatar train. Similar to the preferred embodiment, to the extent possible, it is desirable to provide an “optimum” virtual track space to an avatar train in order for the associated physical train to operate at the maximum allowable operating speed within the ATCS territory. As such,FIG.35reflects an operating scenario, wherein the current virtual track space and associated MAL840for an avatar train839is less than the required optimum virtual track space842. Based on the premise that avatar trains have an assigned level of virtual track space acquisition priority that is higher than that of virtual trains, the autonomous operation of avatar trains includes a rule wherein an avatar train839acquires more track space from a paired virtual train846to satisfy its optimum virtual track space requirements. As such, inFIG.35, avatar train839requests virtual track space from paired front virtual train846to satisfy the requirement for an optimized virtual track space842. In the event the needed virtual track space844is more that the virtual track space845allocated to the virtual train846, the process is repeated until the optimized virtual track space842is satisfied. Alternatively, if the needed virtual track space844is less than the track space845allocated to the virtual train846, then the virtual train846will relinquish the needed track space844to the avatar train839. However, if the remaining virtual track space for the virtual train846is less than a certain threshold, the entire virtual track space845assigned to the virtual train846is relinquished to the avatar train839. In such a case, the virtual train846is retired.

A second characteristic of the avatar train autonomous operation is associated with the operating scenario depicted inFIG.36, wherein the virtual track space852allocated to an avatar train855exceeds a maximum virtual track space threshold852. Similar to the preferred embodiment, it is not desirable for an avatar train to acquire virtual track space way in excess of its optimum virtual track space. As such, one autonomous operation characteristics of avatar train is to relinquish virtual track space when its allocated space exceeds a maximum threshold. An example of an operational scenario that results in excess virtual track space856occurs when a physical train (and associated avatar train) is delayed, and wherein the avatar train keeps accumulating virtual track space from a train ahead that is moving away from its location. InFIG.36, when the virtual track space allocated to avatar train855exceeds the maximum virtual track space threshold852, the avatar train relinquishes the excess virtual track space856for the creation or activation of a new virtual train851.

As indicated above, the autonomous operation of an avatar train in the alternate embodiment is similar to the autonomous operation of a physical train in the preferred embodiment. As such, additional operational scenarios that involve an avatar train are similar to the operational scenarios disclosed in the preferred embodiment. For example, the operational scenario described inFIG.6, wherein a physical train relinquishes track space to a paired autonomous train control element that has a higher assigned level of track space acquisition priority.

With respect to the autonomous operation of an avatar train during a failure condition in the associated physical train, the avatar train detects such failure and communicates the failure information to other train control elements. The failure is detected either based on self-diagnostics of the failed physical train or by loss of communication between the avatar train and the physical train. Failure information, including the identity and characteristics of the failed physical train are propagated within the ATCS using daisy chain communication by paired virtual train control elements. Similar to the preferred embodiment, the alternate embodiment identifies a physical train by a “train signature.”FIG.7shows various design options to provide physical train signature for a train consist161. The various design options are described and explained in the preferred embodiment.

As in the preferred embodiment, virtual trains are logical elements that represent free/unassigned virtual track space, but have a similar operational behavior to avatar trains. These logical elements are implemented as part of the TSC and operate autonomously based on predefined rules. In addition, the autonomous operation of virtual trains in the alternate embodiment is similar to the autonomous operation of virtual trains in the preferred embodiment, except that virtual trains have to interact with avatar trains in lieu of physical trains. In that respect, the autonomous rules that govern the operation of a virtual train in both the preferred and alternate embodiments are similar. Further, the characteristics of the virtual train autonomous operation are similar in both embodiments.

In the alternate embodiment, the virtual interlocking control element (V-IXL) provides the control logic functions for trackside interlocking equipment. The V-IXL communicates with a physical interlocking interface unit through a data communication network. In turn, the interlocking interface unit provides local control functions for the track side interlocking equipment based on control data received from the V-IXL. Further, the interface unit receives status information from the interlocking trackside equipment, and transmits this information to the V-IXL. The characteristics of the autonomous operation of the V-IXL are similar to the characteristics of the autonomous operation of the interlocking control element in the preferred embodiment. Some of the characteristics are related to operating scenarios, wherein the V-IXL acquires virtual track space from paired elements. Other characteristics are related to operating scenarios, wherein the V-IXL relinquishes virtual track space to paired elements. During these operating scenarios, the V-IXL performs various interlocking functions (modify a route, establish new route, modify traffic direction, etc.). Examples of the operating scenarios are shown inFIGS.13,14,16,17,18,19&20, and are described in the preferred embodiment.

The alternate embodiment could also includes a virtual grade crossing control element (V-XING). The V-XING provides the control logic functions for physical grade crossing equipment. The V-XING communicates with a physical grade crossing interface unit through a data communication network. In turn, the grade crossing interface unit provides local control/activation functions for the physical grade crossing equipment based on activation data received from the V-XING. Further, the interface unit receives status information from the grade crossing equipment, and transmits this information to the V-XING. The characteristics of the autonomous operation of the V-XING are similar to the characteristics of the autonomous operation of the grade crossing control element in the preferred embodiment. These characteristics are related to operating scenarios, wherein the V-XING relinquishes/recaptures virtual track space (physical track space in the preferred embodiment) from paired elements. During these operating scenarios, the main function of the V-XING is to provide safe operation of vehicle and rail traffic at an intersection. In general, and as described in the preferred embodiment, the V-XING maintains virtual track space in the approach to and at the associated intersection to allow vehicle traffic to proceed. The V-XING relinquishes virtual track space to paired avatar trains to allow associated physical trains to proceed through the intersection. Further, the V-XING relinquishes virtual track space to other paired elements to allow them to perform various autonomous functions. Examples of the operating scenarios during which virtual track space is exchanged between the V-XING and other virtual train control elements are shown inFIGS.22&23, and are described in the preferred embodiment.

The alternate embodiment also includes an optional virtual Automatic Block Signal Unit (VABSU). The VABSU provides the control logic functions for physical ABSU equipment. The VABSU communicates with a physical ABSU interface unit through a data communication network. In turn, the physical ABSU interface unit provides local control functions for the physical ABSU equipment based on control data received from the VABSU. Further, the interface unit receives status and monitoring data from the physical ABSU equipment, and transmits this information to the VABSU. The characteristics of the autonomous operation of the VABSU are similar to the characteristics of the autonomous operation of the ABSU element in the preferred embodiment. These characteristics are related to operating scenarios, wherein the V-XING relinquishes/recaptures virtual track space from paired elements. During these operating scenarios, the main function of the V-XING is to provide system initialization functions and to support a backup mode of operation during system failures. Further, the interactions between a VABSU and other virtual autonomous train control elements are similar to those described in the preferred embodiment.

The configuration of physical ABSU equipment is similar to the ABSU configuration described in the preferred embodiment and shown inFIG.24. As in the preferred embodiment, the VABSU operates in a plurality of modes. During a passive mode, the VABSU monitors train movements during normal train operation without any impact on train service. During a failure condition (active VABSU mode), the VABSU provides control function that ensures safe train separation for a failed physical train. During its autonomous mode of operation, the VABSU acquires virtual track space from an avatar train or a virtual train moving away from its location. The VABSU controls the physical ABSU equipment to hold a failed physical train, and allows it to proceed only after ensuring that its associated absolute signal block is vacant.FIGS.26&27and associated descriptions in the preferred embodiment provide examples of operational scenarios that demonstrate the characteristics of the autonomous operation of ABSUs. The VABSU also provides control functions during system initialization. More specifically, a VABSU controls the movement of an avatar train and associated physical train into its associated signal block to enable the performance of track sweep, and the initialization of a physical/avatar train into ATCS operation.FIG.28and associated description in the preferred embodiment provide an example of operational scenario for system initialization.

Similar to the preferred embodiment, the alternate embodiment employs a Track Space Controller (TSC), which includes logical elements that provide the autonomous operations for various virtual train control elements. The TCS is implemented in a cloud computing environment to provide a very high level of reliability/availability. The TSC manages the interfaces between virtual train control elements, between virtual elements and associated physical elements, and between virtual elements and external elements in the ATCS operating environment (for example ATS).FIG.37shows a block diagram of the architecture for the TCS in accordance with the alternate embodiment. The TCS899includes elements that are similar to elements included in the TCS of the preferred embodiment. A physical interface module902performs the function of interfacing the various virtual TCS elements with associated physical elements, including physical trains912, interlocking control elements916, grade crossing control elements914and Absolute Block Signal Units (ABSU)918. A data communication network900is used to interconnect the TCS899with the physical elements. In addition, the TCS899includes a diversity of logical modules925,928,930,936&938that are used to provide computing resources for virtual crossing elements, virtual interlocking controllers, virtual ABSUs, virtual trains and avatar trains.

In the alternate embodiment, the operation of the TCS is controlled by the train controller module904, which also controls the creation/activation and retirement of virtual trains, as well as the management of avatar trains. To that extent, an address bus908and a data bus932are used to enable the train controller module904to control the operation of the various modules included in the TCS899. It should be noted, and as would be understood by a person skilled in the art, that a separate TCS processor could be used to control the operation of the TCS. In such an embodiment, one of the main functions of the train controller module904is to create/activate and retire of virtual trains. Upon receiving a request from a virtual train control element to create or activate a new virtual train, the train controller904selects and activates a “spare” logical element934to provide the computing resources for the newly created virtual train. The train controller904assigns a unique train ID to the newly created virtual train, as well as an initial location that must be confirmed with the virtual autonomous train control element that requested the creation of the new virtual train. Further, the train controller904communicates with the Communication Interface Controller CIC910via the CIC Interface920requesting that the newly created virtual train be paired with the virtual autonomous train control element that requested the creation of the virtual train. In turn, the paired virtual autonomous train control element confirms the location of the new virtual train and relinquishes virtual track space to it.

Alternatively, under certain operating conditions, a virtual autonomous train control element requests the retirement of a virtual train. An example of such operating conditions is during the initialization of a physical/avatar train. Typically for the preferred embodiment, a physical/avatar train is initialized as a replacement of an existing virtual train, and by acquiring its allocated virtual track space. The virtual train is then switched to a standby mode or state (“standby mode”), its logical element is spared, and the avatar train receives an initial movement authority limit associated with the retired virtual train. This movement authority limit is adjusted to account for the length of the associated physical train. In general, upon receiving a request from a virtual autonomous train control element to retire a virtual train, the train controller904acknowledges the request and informs the virtual train control element of a “pending” status of the request. The virtual train control element then acquires the virtual track space assigned to the virtual train, and confirms to the train controller904that the virtual train is ready to be retired. Upon receiving such confirmation, the train controller904retires the virtual train and assigns a “spare” status to the corresponding logical module934.

Further, the TSC899has the function of initializing a new avatar train when a physical train enters or is activated in the ATCS territory. When a new physical train establishes communication with the TSC899, the train controller904assigns a spare logical module939to operate as an avatar train it. In addition, at the time the ATCS system is configured, fixed location physical elements are assigned logical elements within the TSC899. For example, a physical interlocking element916is assigned a logical module928to operate as a virtual interlocking control element, a physical ABSU element918is assigned a logical element928to act as a virtual ABSU, and a physical grade crossing element914is assigned a logical element925to act as a virtual grade crossing control element. In addition to providing autonomous control functions, the logical elements store real time data related to the operational statuses of the corresponding physical train control elements. Also, the logical elements provide relevant data to the CIC910to effect the pairing process. The real time data includes operational and maintenance data related to physical/virtual elements and is used to provide train location and status information for the Automatic Train Supervision displays as well as for maintenance functions.

The TSC899further includes a Simulation Engine Module924that provides nominal operating speeds for the various virtual trains operating in the ATCS territory. The nominal operating speeds are based on the average operating speeds of avatar trains938, which receive operational data from associated physical trains912operating at various sections of the ATCS territory, as well as civil speed limits. In addition, the TSC899includes two memory modules that provide line data necessary for the operation of the autonomous virtual train control elements. The line data memory unit922stores track geometry information including data for grades, curves, super elevation, station platforms, civil speed limits, locations of wayside equipment, etc. Similarly, interlocking data memory unit926stores data related to interlocking configuration, route and traffic patterns, track switch information, etc. In the alternate embodiment, the line data is downloaded from the Automatic Train Supervision (ATS) system via the ATS interface module906. In turn, relevant line data is provided to avatar trains938, which in turn download relevant data to associated physical trains912at the time they are initialized in ATCS operation. In addition the ATS system provides itinerary data for each avatar train to control and regulate its movement through the ATCS territory. The train itinerary data includes train destination, identity of interlocking routes, required station stops, schedule data, etc. Further, the ATS system can issue direct commands to avatar trains that impact normal scheduled operation. These commands include skip station stop, hold train at station, emergency stop, change itinerary, etc. Also, the ATS system provides line/train regulation data that is sent in the form of performance parameters to avatar trains, and then transmitted to associated physical trains. In addition, and as disclosed above, operational parameters of virtual trains could be used for the purpose of train regulation.

The physical interface unit902provides the needed wireless communication interfaces, via wireless communication network900, between trackside physical elements912,914,916&918and corresponding logical modules938,925,928&930. It should be noted that communications between paired virtual train control elements are managed by the Communication Interface Controller910based on operational data provided by the TSC899. Also, the CIC910provides initial communication links for physical trains as they enter the ATCS territory.

Similar to the preferred embodiment, the alternate embodiment includes an ATCS element defined as the Communication Interface Controller (CIC). The CIC's main function is to dynamically manage in real time the pairing of various virtual ATCS elements. In general, the CIC receives location information from the Track Space Controller (TSC), and assigns communication channels to paired virtual ATCS elements. Further, in the alternate embodiment, the CIC manages the allocation of fixed communication links between virtual train control elements that are associated with fixed location physical elements. The general CIC architecture proposed for the alternate embodiment is shown inFIG.38. It should be noted, and unlike the preferred embodiment, the communication channels needed for communications between the virtual train control elements reside within the TSC899. As such, one design choice is for the CIC to provide addressing information for the various logical modules to communicate in dynamic pairing configurations.

The CIC910includes a CIC processor950that control the operation of the CIC unit, a plurality of pairing memory modules952,954,956,958,960,968,970,972&974, a data bus962, an address bus964, and an interface to the data communication network900. The main function of a pairing memory module is to store in real time the identity (or address) information of the virtual ATCS elements paired together, as well as data related to the communication links used for the paired communications. To that extent, and to facilitate the implementation of the pairing process, the alternate embodiment employs an architecture that includes different types of modules. There are modules that include two cells952,956,958&960, which are used for the pairing of two virtual ATCS elements. Further, there are modules that include three cells954,968,970,972&974, which are used for the pairing of three virtual ATCS elements. In general, a three-cell module is used to pair a fixed location element (VIXL916, VXING914& VABSU918) with avatar and/or virtual trains. Also, certain two-cell modules960are used to pair or provide communication links between fixed location virtual elements. Other two-cell modules956are used to pair moving virtual ATCS elements. Spare modules958are provided to accommodate increased traffic conditions. In addition, a number of cells952are dedicated for incubator functions to establish initial communication between newly initialized physical trains and the TSC899. It should be noted that in the alternate embodiment, one design choice is to integrate the CIC910as part of the TSC architecture899. In such configuration, the TSC performs the functions performed by the CIC.

It should be noted that the foregoing detailed descriptions of the preferred and alternate embodiments have been given to demonstrate the various disclosed concepts and functions. As would be understood by a person skilled in the art, there are different design choices to implement the concepts presented herein. It should also be noted that the various autonomous elements disclosed in the preferred and alternate embodiments can utilize alternate vital programs to implement the described autonomous 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 descriptions of the preferred and alternate embodiments have been given for clearness of understanding only, and are 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.