Railway control systems

Abstract

A railway control system comprises multiple train control systems (e.g. Radio Block Centres (RBC)) 105, 106 located along a railway track 102. The first train control system 105 determines a route and

Description

Field of the Disclosure The present disclosure relates to railway control systems. Background of the Disclosure Railway control systems are used to control the movement of trains along a railway track. An objective of such control systems is to optimise utilisation of the railway track by trains whilst ensuring the safety of the trains. An implementation of railway control systems is to supervise trains using automated train control systems distributed along the railway track that communicate with the trains to exchange control information as the train travels along a respective section of the track. As trains pass between track sections supervised by different train controllers, the preceding train controller communicates the train control information to the succeeding train controller. Summary of the Disclosure A first aspect of the present disclosure provides a method for operating a railway control system comprising a plurality of train control systems located along a railway track, the method comprising: determining by a first of the train control systems a route of a train, determining by the first train control system a position of the train, determining by the first train control system based on the route of the train and on the position of the train a portion of the railway track included in the route that is located ahead of the train, determining by the first train control system an operating parameter for the train to travel along the portion of the railway track, sending by the first train control system a signal representing the determined operating parameter to a second of the train control systems. Each section of the railway track may thus be assigned to a respective one of the plurality of trackside train control systems. In this arrangement, as a train travels along the track, it may communicate with the train control system associated with the respective section of track, to thereby exchange train control information, such as the operating parameter information, with the respective train control system, and ultimately with any other control systems communicating with the train control system. When the train proceeds onto the next section of track, it may cease communication with the preceding train control system and establish communication with the succeeding train control system. To facilitate efficient and safe handling of a train as it enters a new section of track, the preceding train control system may supply the operating parameter information, to the succeeding train control system. This procedure is known in the technical field as a ‘handover’. In order to avoid delaying a train as it progresses between sections of track associated with different radio block centres, all or part of the handover procedure may be initiated before the train reaches the border between the track sections. Thus, the preceding train control system may send the operating parameter information onto the succeeding train control system before the train leaves the section of track associated with the preceding train control system. This is known in the technical field as a ‘pre-announcement’. Preannouncing avoids delaying trains at borders between sections of track, and in theory allows the trains to safely travel uninhibited between sections of track. However, a potential issue arises in practice with pre-announcing a train, in that train control information, such as the operating parameter of the train, may change, potentially multiple times, between the time that the train has been preannounced by the preceding train control system to the succeeding train control system and the time that the train actually reaches the border between the sections of track. This may present a control problem, in that the succeeding train control system may be expecting the train to cross the border onto its section of track with the preannounced operating parameters, whereas the train may actually cross the border with different operating parameters. This may cause operational difficulties, which may complicate control of the train and / or slow progress of trains along the track. An approach to reducing the risk of the operating parameter changing after the preannouncement is sent and before the train reaches the border is to delay sending of the pre-announcement until the train is very close to the border. At this time, the train may report its operating parameter to the preceding train control system, which may in turn preannounce that operating parameter to the succeeding train control system. Thus, a risk of the operating parameter of the train subsequently changing before the border may be reduced. However, this may present an operational hazard, in that the late transmission by the preceding train control system may not provide the succeeding train control system sufficient time to process the pre-announced information and take any according action. And in the event of a failed transmission of the preannouncement insufficient time may be available to repeat the pre-announcement transmission before the train reaches the border. The present disclosure thus approaches this problem by predicting the operating parameter for the train to cross the border ahead of time before the train actually reaches the border. That is to say, the preceding, first, train control system determines the operating parameter for a portion of the track that is located ahead of the train, i.e., before the train has reached that portion of the track. For example, the preceding train control system may determine ahead of time an operating parameter for the train for a portion of the track located at the end of the first section of the track contiguous with the border with the second section of track. And then the preceding train control system sends that predicted operating parameter to the succeeding, second, train control system. Consequently, the pre-announcement may be sent relatively early, in good time before the train arrives at the border, yet a risk of the pre-announced operating parameter being incorrect when the train crosses the border is reduced. As a result, a risk of the train being delayed as it crosses the border between sections may be reduced, and accordingly train throughput may be improved. The disclosure is useful, for example, in the context of an Automatic Train Protection system (ATP) compliant with the European Train Control System (ETCS) standards. Within these standards, systems that are functionally similar to the presently disclosed train control systems are commonly referred to as radio block centres. In an implementation, the method comprises determining by the first train control system if the position of the train meets position criteria. In other words, the first train control system may perform a check that the determined position of the train satisfies certain criteria, for example, predefined position criteria. In an implementation, the sending by the first train control system the signal is performed based on a determination by the first train control system that the position of the train does meet the position criteria. In other words, the first train control system may delay sending the pre-announcement signal until the position of the train meets particular criteria. For example, the position criteria could be a distance of the train from an end of the section of track, and so the start of the next section of track, and this step may thus involve the first train control system determining whether the train is sufficiently close to the border before the pre-announcement is sent. This may avoid sending of the pre-announcement message too early, and so reduce a risk of the pre-announced operating parameter being incorrect when the train crosses the border is reduced. As a result, a risk of the train being delayed as it crosses the border between sections may be reduced, and accordingly train throughput may be improved. In an implementation, the method comprises repeating the determining by the first train control system if the position of the train meets the position criteria in response to an initial determination that the position of the train does not meet the position criteria. In other words, the first train control system may repeatedly determine whether the train meets the position criteria, e.g., to check whether the train is sufficiently close to the border to send the pre-announcement signal. This may avoid sending of the pre-announcement message too early, and so reduce a risk of the pre-announced operating parameter being incorrect when the train crosses the border is reduced. As a result, a risk of the train being delayed as it crosses the border between sections may be reduced, and accordingly train throughput may be improved. In an implementation, the method comprises receiving by the first train control system train position data representing the position of the train, wherein the determining by the first train control system a position of the train is performed based on the train position data. In other words, the train may self-report its position to the first train control system. This may be a relatively computationally simple way for the train control system to locate the train. In an implementation, the method comprises determining by the first train control system a condition of the portion of railway track, wherein the determining by the first train control system the operating parameter is performed based on the condition of the portion of railway track. In other words, the first train control system may determine the condition of the portion of the track ahead for which the operating parameter is to be predicted, and determine the operating parameter based on that track condition. Accordingly, the operating parameter may be tailored to the prevailing track conditions, and thus operational safety of the train may be improved. In an implementation, the method comprises receiving by the first train control system railway track condition data representing a condition of the portion of the railway track. For example, the train control system could receive the track condition data from a track interlocking system. In an implementation, the receiving by the first trail control system the track condition data comprises receiving by the train control system track condition data representing a condition of a section of the railway track that includes the portion of the railway track wherein the railway track condition data is associated with a respective position of the railway track, the method comprising determining by the first train control system a part of the railway track condition data associated with the portion of the railway track, and wherein the determining by the first train control system the operating parameter is performed based on the part of the railway track condition data. In other words, the first train control system may receive aggregated track condition data, and the method may involve the train control system extracting a segment of that aggregate data that corresponds to the portion of track for which the operating parameter is to be predicted. Receiving the track condition data in aggregate form may desirably reduce a time for which a network connecting the train control system to the source of the track condition, e.g., the interlocking, is utilised. In an implementation, the method comprises sending by the first train control system a further signal representing the determined operating parameter to the train. The predicted operating parameter may thus also be sent to the train, to be applied by the train when it eventually reaches the portion of track. In an implementation, the method comprises receiving by the second train control system the signal representing the determined operating parameter sent by the first train control system. In an implementation, the method comprises determining by the second train control system a position of the train, determining by the second train control system if the position of the train meets position criteria. In other words, the second train system may check that the position of the train is within a section of track assigned to the second train control system. For example, the position criteria could be a range of positions assigned to the second train control system. Thus, the second train control system may detect when the train has reached its area of responsibility. In an implementation, the method comprises determining by the second train control system, in response to a determination that the position of the train does meet the position criteria, whether the operating parameter is valid by reference to validity data. In an implementation, the method comprises determining by the second train control system, in response to a determination that the operating parameter is not valid, a further operating parameter for the train to travel along a further portion of the railway track. The second train control system may thus, on detecting that the train has entered its area of responsibility, perform a check to identify whether the train should be allowed to continue based on the operating parameter inherited from the first train control system, or whether a new operating parameter should be determined. For example, the validity data could be an extent to which the train has progressed into the area of responsibility, or could be whether incompatible track condition data has been received by the second train control system. A second aspect of the present disclosure provides a railway control system comprising a plurality of train control systems suitable for location along a railway track, the railway control system being configured to perform the method of any of the preceding statements. A third aspect of the present disclosure provides a computer program comprising instructions, which, when executed by a railway control system causes the railway control system to carry out the method of any of the preceding statements. A fourth aspect of the present disclosure provides a computer-readable data carrier having the computer program of the preceding statement stored thereon. These and other aspects of the invention will be apparent from the embodiment(s) described below. Brief Description of the Drawings In order that the present invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows schematically an example of a railway embodying the present disclosure, comprising a plurality of train control systems located along a railway track; Figure 2 shows schematically components of each of the train control systems; Figure 3 shows schematically a method performed by each of the train control systems to control a train on the railway track, which includes a process of handing over a train by a train control system, accepting a train by a train control system, and supervising a train by a train control system; Figure 4 shows processes involved in the process of handing over a train by a train control system; and Figure 5 shows processes involved in the processes of accepting a train by a train control system, and supervising a train by the train control system. Detailed Description of the Disclosure An example of a railway 101 embodying the present disclosure is depicted schematically in Figure 1. An example method of operating the railway 101 embodying the present disclosure will be described herein with particular reference to Figures 3 to 4. The railway 101 comprises a railway track 102 and a train 103 running on the railway track 102. The railway 101 further comprises a railway control system, which comprises a plurality of train control systems 105, 106 located trackside along the railway track 102, one or more track control systems 107 located trackside along the railway track 102, and plural trackside beacons 108, 109 also located along the railway track 102. The components of the railway 101 are not depicted to scale in the Figures. For the purposes of the example operation described herein, the train 103 is described as travelling from the left to the right of the Figure. The train 103 comprises an onboard motion control system 110 operable to control the motion of the train, a radio receiver 111 operable to receive radio signals from the trackside beacons 108, 109, and a radio transceiver 112 operable to receive and transmit radio signals to communicate with the train control systems 105, 106. The radio transceiver 112 could, for example, comprise a Global System for Mobile communications protocol device (GSM). The onboard motion control system 110 may further comprise a speed sensor, for example, an axle sensor for sensing a speed of motion of the train. The track control system 107 is provided for the purpose of configuring and monitoring the condition of the railway track 102, and monitoring the movement of trains along the railway track 102. The track control system 107 comprises sensors for monitoring various conditions of the track, for example, track characteristics such as the configuration of points on the track. The track control system 107 communicates with the train control systems 105, 106 via an ethemet network. A particular objective of the track control system 107 is to ensure the safety of trains travelling along the railway track 102, by ensuring that conflicting train movements, e.g., two trains travelling on a same section of track at a same time, is avoided, and ensuring that track points are correctly configured. The track control system 107 may thus define operational restrictions for trains running on the track, for example, positions to which a train may proceed. In the technical field, systems that are functionally similar to the track control system 107 are commonly referred to as an interlocking system, and for clarity this terminology will be used herein. The train control systems 105, 106 are provided for the purpose of communicating control information with the train 103 as it travels along the track 102. Such control information may include the train reporting its current position and speed to the train control system, and the train control system providing permissions to proceed and operating parameters to the train. The train control systems 105, 106 may also convey track condition data and other information from the track control system 107 to trains running on the track. Each of the train control systems 105, 106 comprises onboard processing resource for processing data and a radio transceiver 114 for communicating with the train 103. The radio transceiver 114 could, for example, comprise a Global System for Mobile communications protocol device (GSM). In the technical field, systems that are functionally similar to the train control systems 105, 106 are commonly referred to as Radio Block Centres (RBC), and for clarity this terminology will be used herein. The trackside beacons 108, 109 function as transponders, and are utilised by the train 103 as passive positioning devices. When the train 103 passes over a trackside beacon the antenna 111 of the train’s onboard control unit 110 energises the beacon and reads the characteristic radio signal generated by the trackside beacon. From the received signal the train 103 may determine its position, for example, by reference to a pre-defined lookup table stored by the onboard control unit 110 associating positions with characteristics of the signals received from the beacons 108, 109. In combination with the speed sensors of the onboard motion control system 110, the onboard motion control unit 110 may thereby utilise the trackside beacons 108, 109 to determine aposition of the train as it travels along the track. In the technical field, systems that are functionally similar to the trackside beacons 108, 109 are commonly referred to as a balise, and for clarity this terminology will be used herein. Within the control method implemented by the railway control system, the railway track 102 is notionally sub-divided into a plurality of successive sections, such as a first section of railway track 115, and a second section of railway track 116 located after the first section 115 in the example direction of motion of the train 103. Within this scheme, each section of the track is assigned to a respective one of the radio block centres 105, 106. Thus, in the example, the first track section 115 is assigned to the first radio block centre 105. Whereas, the second track section 116 is assigned to the second radio block centre 106. In this arrangement, as the train 103 travels along the track 102, it communicates with the radio block centre associated with the respective section of track, to thereby exchange control information with the radio block centre, and ultimately with any other control systems communicating with the radio block centre, e.g., the interlocking. When the train proceeds onto the next section of track, it ceases communication with the current radio block centre and establishes communication with the radio block centre associated with the new section of track. Thus, in the example depicted in Figure 1, train 103 may communicate with the first radio block centre 105 to exchange control information when the train is located on the first section of track 115, and when the train proceeds onto the second section of track 116 the train may cease communication with the first radio block centre 105 and establish communication with the second radio block centre 106. In particular, an operating parameter provided to the train by the radio block centre may include an operating mode of the train, known in the technical field as an ‘M_Mode’. The ‘M_Mode’ effectively defines a level of supervision that the train driver is required to assume for operating the train. Where the radio block centre is able to determine with certainty, e.g., from information received by the radio block centre from the interlocking and / or from the train, that a section of track is clear from obstruction, the radio block centre may issue a ‘Full-Supervision’ (FS) permission to proceed to the train. In this instance, the radio block centre is effectively assuming full responsibility for the train, allowing the train to proceed at maximum speed with minimum responsibility on the driver to intervene. Alternatively, where the radio block centre is unable to determine whether a section of track is clear of obstructions, for example, due to a failure in communications between the radio block centre and the interlocking, the radio block centre may issue an ’On-Sight’ (OS) permission to proceed to the train. In this instance, the train driver is required to assume responsibility for detecting track obstructions and braking the train. Thus, the maximum speed of the train, and so throughput of the line, may be disadvantageously reduced. To facilitate efficient and safe handling of a train as it enters a new section of track, the preceding radio block centre supplies train control information to the succeeding radio block centre. For example, as the train 103 progresses from the first section 115 of track 102 to the second section of track 116, the first radio block centre 105 will send a radio signal to the second radio block centre 106 notifying the second radio block centre 106 of the train control information. This procedure is known in the technical field as a ‘handover’. Such control information provided in the handover may include an identification number of the train and various operating parameters for the train, such as the M_Mode. In the technical field, the preceding radio block centre e.g., the first radio block centre 105, is referred to as the ‘handover’ radio block centre, and the succeeding radio block centre, e.g., the second radio block centre 106, is referred to as the ‘accepting’ radio block centre, and this terminology will be used herein. In order to avoid delaying a train as it progresses between sections of track associated with different radio block centres, all or part of the handover procedure may be initiated before the train reaches the border between the track sections. Thus, the handover radio block centre may send the train control information, e.g., the M_Mode, to the accepting radio block centre before the train leaves the section of track associated with the handover radio block centre. This is known in the technical field as a ‘pre-announcement’. Pre-announcing avoids delaying trains at borders between sections of track, and in theory allows the trains to safely travel uninhibited between sections of track. However, a potential issue arises in practice with pre-announcing a train, in that operating parameters of the train may change, potentially multiple times, between the time that the train has been preannounced by the handover radio block centre to the accepting radio block centre and the time that the train actually reaches the border between the sections of track. This may present a control problem, in that the accepting radio block centre may be expecting the train to cross the border onto its section of track with the preannounced operating parameters, whereas the train may actually cross the border with different operating parameters. For example, referring to the example scenario illustrated in Figure 1, the first, handover, radio block centre 105 may send a pre-announcement containing the current operating parameters to the second, accepting, radio block centre 106 when the train 103 is at the illustrated location. However, the illustrated location is some distance from the border 117 between the first and second sections of track 115, 116, in practice potentially several kilometres, and there thus exists an undesirable possibility that operating parameters of the train 103 may change before the train arrives at the border 117. For example, the handover radio block centre 105 may subsequently determine that a condition of the track between the train’s current position and the border 117 is potentially degraded, for example, due to condition data relating to the track ahead provided by the interlocking 107. Thus, the first radio block centre 105 may subsequently compute and send to the train 103 alternative operating parameters appropriate to the degraded track condition, for example, a downgraded M_Mode. An approach to reducing the risk of the train operating parameters changing after the preannouncement is sent and before the train reaches the border is to delay sending of the preannouncement until the train is very close to the border. Thus, a risk of the operating parameters of the train subsequently changing before the border may be reduced. However, this may present an operational hazard, in that the late transmission by the handover radio block centre may not provide the accepting radio block centre sufficient time to process the pre-announced information and take any according action. And in the event of a failed transmission of the pre-announcement insufficient time may be available to repeat the pre-announcement transmission before the train reaches the border. An alternative approach is for the handover radio block centre to predict operating parameters for the train to cross the border ahead of time before the train actually reaches the border. The handover radio block centre may then send the predicted operating parameters in the preannouncement to the accepting radio block centre. Consequently, the pre-announcement may be sent relatively early, in good time before the train arrives at the border, yet a risk of the preannounced operating parameters being incorrect when the train crosses the border is reduced. As a result, a risk of the train being delayed as it crosses the border between sections may be reduced, and accordingly train throughput may be improved. Thus, in the example illustrated in Figure 1, when the train 103 is located at the illustrated position of the first section of track 115, which may be approximately midway along the first section of track 115, the first radio block centre 105 may predict one or more operating parameters that will be appropriate for the train 103 to travel along an end portion 118 of the first section of track 115 located ahead of the train 103 and contiguous with the border 117. For example, the first radio block centre 105 may predict an appropriate M_Mode for the train 103. The first radio block centre 105 may then issue a pre-announcement radio signal to the second radio block centre 106 containing the predicted M_Mode data. The radio block centres 105, 106 are substantially like, and for brevity therefore only the first radio block centre 105 will be described herein in detail, on the understanding that substantially the same teaching applies to radio block centre 106 also. Referring next to Figure 2, in examples, each of the radio block centres 105, 106 comprises a processor 201, memory 202, radio transceiver 114, input / output device 203 and system bus 204. Each of the radio block centres 105, 106 is configured to run a computer program for controlling the operation of trains on the railway track 102. Processor 201 is configured for execution of instructions of the computer program for controlling the operation of trains on the railway. Memory 202 is configured for non-volatile storage of the computer program, defining machine-readable instructions, for execution by the processor, and for serving as read / write memory for storage of operational data associated with computer programs executed by the processor 201. Radio transceiver 114 is configured for communicating by radio with trains running on the track 102, e.g., train 103, and with other of the radio block centres,. Radio transceiver 114 may, for example, operate as a GSM protocol transceiver. Input / output interface 203 is configured for connection of the radio block centre 105, 106 to other external systems, e.g., for connection to an ethemet protocol local area network to enable communication with the interlocking 107. The components 201, 202, 114, and 203 of the radio block centre 105, 106 are in communication via system bus 204. Referring next to Figure 3, in examples the computer program for controlling trains on the railway track 102 implemented by each of the radio block centres 105, 106 comprises three operations 301 to 303. In Figure 3, the operations are presented in an example order to be consistent with the scenario illustrated in Figure 1, in which the first radio block centre 105 hands over responsibility for the train 103 to the second radio block centre 106. At operation 301, the computer program causes the processor 201 of the first radio block centre 105 to handover responsibility for the train 103 to the second radio block centre 106. Processes involved in the first radio block centre 105 handing over the train 103 will be described in further detail with reference to Figure 4. At operation 302, the computer program causes the processor 201 of the second radio block centre 106 to accept responsibility for supervision of the train 103 after the train 103 has crossed the border 117. Processes involved in the second radio block centre 106 accepting the train 103 will be described in further detail with reference to Figure 5. At operation 303, the computer program causes the processor 201 of the second radio block centre 106 to supervise the train 103 as it travels along the second section of track 116. Processes involved in the second radio block centre 106 supervising the train 103 will be described in further detail also with reference to Figure 5. It should be understood that in the example the operations 301 to 303 may be performed by each of the radio block centres in turn as the train progresses along the track. That is to say that each radio block centre will firstly perform operation 301 to accept responsibility for the train from the preceding radio block centre as the train enters the section of track assigned to that radio block centre. Then that radio block centre will perform operation 302 to supervise the train along its assigned section of track. And then the radio block centre will perform operation 303 to handover responsibility for the train to the succeeding radio block controller when the train leaves that section of track. Referring next to Figure 4, operation 301 performed by the first radio block centre 105 for handing over responsibility for supervising the train 103 to the second radio block centre 106 involves eight processes. At process 401, the computer program causes the processor 201 of the first radio block centre 105 to receive position data from the train 103. Process 401 could, for example, involve the processor 201 operating the transceiver 114 to receive a radio signal from the train 103 whereby the train 103 reports position data generated based on the signal received from the balise 108 and onboard speed sensors. At process 402, the computer program causes the processor 201 of the first radio block centre 105 to determine the position of the train 103 based on the position data received at process 401. Process 402 could, for example, involve the processor 201 processing aggregated data received at process 401 to extract the relevant position data, or performing some other processing operation. As an alternative to processes 401 and 402, process 401 could be omitted, and process 402 could involve the first radio block centre 105 determining a position of the train 103 by alternative means, for example, by communicating with other sensors to sense a position of the train 103. At process 403, the computer program causes the processor 201 of the first radio block centre 105 to determine whether the position of the train 103 determined at process 402 meets particular position criteria. An object of process 403 is to determine whether the train 103 is in the appropriate position with respect to the border 117 between the first and second sections of track 115, 116 to send the pre-announcement message to the second radio block centre 106. It may be desirable to avoid sending the pre-announcement message excessively early, as sending the message too early may increase a risk of the train operating parameters announced in the preannouncement changing before the train reaches the border 117, for example, resulting from unexpected degradation of the track condition. Whereas, as previously described, it may be desirable to send the pre-announcement message with sufficient time before the train 103 reaches the border 117 for the second radio block centre 106 to take any appropriate actions, etc. The position criteria could therefore be a distance from the border 117 value, and process 403 may thus involve the processor 201 comparing the position of the train 103 to the position of the border 117 and determining if that distance is equal to or less than the position criteria. The position criteria, e.g., the distance from the border 117 value, could be predefined and stored in the memory 202 of the first radio block centre 105. As an example alternative, the position criteria could be received by the first radio block centre dynamically from an external source, e.g., from the interlocking 107 via the radio transceiver 114. Ifat process 403 it is determined that the current position of the train 103 does not meet the position criteria, e.g., that the train 103 is not sufficiently close to the border 117, the processor may pause and revert to executing processes 401 and 402 to receive further position data from the train 103 at a later time, and the processor may cycle through stages 401 to 403 repeatedly until process 403 is answered in the affirmative, indicating that the train does meet the position criteria, e.g., that the train is sufficiently close to the border 117. When process 403 is answered in the affirmative, the processor 201 may proceed to process 404 of the computer program. At process 404, the computer program causes the processor 201 of the first radio block centre 105 to retrieve route information for the train 103; that is information defining a route of the train 103. This route information could, for example, be provided to the first radio block centre 105 by the train 103 in response to a request issued by the first radio block centre 105 to the train at process 404, or could, for example, be provided to the first radio block centre 105 by the preceding radio block centre as a part of an earlier handover procedure. At process 405, the computer program causes the processor 201 of the first radio block centre 105 to determine a portion of the track that is ahead of the train, based on the position of the train 103 determined at process 402 and on the route of the train determined at process 404. This will be the portion of the track 102 for which the first radio block centre 105 will predict suitable operating parameters for the train 103. In the example previously described with reference to Figure 1, this may be the end-portion 118 of the track that is located immediately before the border 117, and is thus the portion of the track from which the train 103 will pass across the border 117 into the second section of track 116. At process 406, the computer program causes the processor 201 of the first radio block centre 105 to retrieve track condition data from the interlocking 107 representing a condition of the portion of track. For example, in process 406 the track condition data could be provided by the interlocking in response to a request issued by the first radio block centre 105. As an example alternative, the track condition data could have been provided to the first radio block centre 105 by the interlocking 107 at an earlier time, and process 406 could involve the processor 201 retrieving the track condition data from memory 202. At process 407, the computer program causes the processor 201 of the first radio block centre 105 to determine an operating parameter for the train 103 to travel along the end portion 118 of the first section of track 115. For example, process 407 may involve the processor 201 processing the track condition data retrieved at process 406, and / or may involve the processor 201 processing other data, e.g., data relating to the characteristics of train 103 which could be communicated to the first radio block centre 105 by the train, e.g., at process 401. At process 408, the computer program causes the processor 201 of the first radio block centre 105 to send the pre-announcement message to the second radio block centre 106. In the example, this may involve the radio transceiver 114 of the first radio block centre 105 generating a radio transmission for reception by the radio transceiver 114 of the second radio block centre 106. Operation 301 may further involve the first radio block centre 105 sending the determined operating parameter to the train 103 also, such that the onboard motion control unit 110 of the train 103 may subsequently implement that operating parameter when it reaches the end-portion 118 of the first section of track 115. Referring next to Figure 5, operation 302 performed by the second radio block centre 106 for accepting responsibility for supervising the train 103 from the first radio block centre 105 involves eight processes. At process 501, the computer program causes the processor 201 of the second radio block centre 106 to receive the pre-announcement signal transmitted by the first radio block centre 105. At process 502, the computer program causes the processor 201 of the second radio block centre 106 to establish communication with the train 103. Process 502 may, for example, involve the radio transceiver 114 of the second radio block centre 106 sending a communication initiation request to the train 103. At process 503, the computer program causes the processor 201 of the second radio block centre 106 to receive position data from the train 103. Process 503 could, for example, involve the radio transceiver 114 of the second radio block centre 106 sending a request to the train 103 for the position data. Alternatively, process 503 could involve the second radio block centre 106 passively monitoring for the train 103 to itself initiate sending of position data to the second radio block centre 106. At process 504, the computer program causes the processor 201 of the second radio block centre 106 to determine whether the position of the train 103 meets particular position criteria. An object of process 504 is to determine whether the train 103 has actually crossed the border 117 and advanced into the second section of track 116. The position criteria applied at process 504 may therefore be a position of the border 117, that being the beginning of the second section of track 116 and so the area of responsibility of the second radio block centre 106. The determination may therefore be whether the position of the train 103 is after the position of the border 117, and so whether the second train control system 106 should yet assume responsibility for the train 103. If the determination at process 504 is that the train’s position does not meet the position criteria, e.g., that the train 104 has not yet advanced past the border 117, the computer program causes the processor 201 of the second radio block centre 106 to return to pause and return to process 503, whereby more position data for the train is collected, and then compared to the position criteria at process 504. Processes 503 to 504 may thus be performed repeatedly by the processor 201 of the second radio block centre 106. When the determination at process 504 is that the position of the train 103 does meet the position criteria, e.g., that the train 103 has crossed the border 117 onto the second section of track 116, the processor 201 of the second radio block centre 106 may progress to performance of process 505. At process 505, the computer program causes the processor 201 of the second radio block centre 106 to determine whether the pre-announced operating parameter received at process 501 remains valid. An object of process 505 is to determine whether the second radio block centre 106 should determine another operating parameter for the train 103, or whether the train 103 should be allowed to proceed further along the second section of track 116 using the operating parameter received in the pre-announcement at process 501. Process 505 could, for example, involve the processor 201 of the second radio block centre determining whether the train 103 has yet advanced to a particular position of the second section of track 116. In such a scenario, the second radio block centre 106 may allow the train 103 to proceed to a particular position of the second section of track 102 using the operating parameter inherited from the first radio block centre 105. Whereas, after a particular position of the second section of track 116, the second radio block centre 106 may provide anew operating parameter. If the determination at process 505 is that the operating parameter remains valid, the processor 201 may pause and return to process 503 and repeat processes 503 to 505. If the determination at process 505 is that the operating parameter is not valid, the processor 201 may proceed to perform process 506. At process 506, the computer program causes the processor 201 of the second radio block centre 106 to receive further track condition data from the interlocking 107. For example, process 506 may involve the processor 201 sending a request for track condition for the second section of track via the radio transceiver 114 to the interlocking 107. At process 507, the computer program causes the processor 201 of the second radio block centre 106 to determine a further operating parameter for the train 103. The process of stage 507 could be similar to the process of stage 407, whereby the processor 201 determines the new operating parameter based on the track condition data received at process 506. At process 508, the computer program causes the processor 201 of the second radio block centre 106 to send the further operating parameter determined at stage 507 to the train 103, for example, via the radio transceiver 114. Referring still to Figure 5, operation 302 performed by the second radio block centre 106 for supervising the train along the track section may involve the processor 201 of the second radio block centre 106 repeatedly performing processes 506 to 508. Thus, the second radio block centre 106 may continuously receive track condition data from the interlocking, and / or other data, e.g., condition data from the train, and may periodically determine new operating parameters for the train 103 to proceed along the second section of track 116. Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims._In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.

Claims

1. A method for operating a railway control system comprising a plurality of train control systems located along a railway track, the method comprising:determining by a first of the train control systems a route of a train,determining by the first train control system a position of the train,determining by the first train control system based on the route of the train and on the position of the train a portion of the railway track included in the route that is located ahead of the train,determining by the first train control system an operating parameter for the train to travel along the portion of the railway track,sending by the first train control system a signal representing the determined operating parameter to a second of the train control systems.

2. The method of claim 1, comprising determining by the first train control system if the position of the train meets position criteria.

3. The method of claim 2, wherein the sending by the first train control system the signal is performed based on a determination by the first train control system that the position of the train does meet the position criteria.

4. The method of claim 3, comprising repeating the determining by the first train control system if the position of the train meets the position criteria in response to an initial determination that the position of the train does not meet the position criteria.

5. The method of any one of the preceding claims, comprising receiving by the first train control system train position data representing the position of the train, wherein the determining by the first train control system a position of the train is performed based on the train position data.

6. The method of any one of the preceding claims, comprising determining by the first traincontrol system a condition of the portion of railway track, wherein the determining by the first train control system the operating parameter is performed based on the condition of the portion of railway track.

7. The method of claim 6, comprising receiving by the first train control system railway track condition data representing a condition of the portion of the railway track.

8. The method of claim 7, wherein the receiving by the first trail control system the track condition data comprises receiving by the train control system track condition data representing a condition of a section of the railway track that includes the portion of the railway track wherein the railway track condition data is associated with a respective position of the railway track, the method comprising determining by the first train control system a part of the railway track condition data associated with the portion of the railway track, and wherein the determining by the first train control system the operating parameter is performed based on the part of the railway track condition data.

9. The method of any one of the preceding claims, comprising sending by the first train control system a further signal representing the determined operating parameter to the train.

10. The method of any one of the preceding claims, comprising receiving by the second train control system the signal representing the determined operating parameter sent by the first train control system.

11. The method of any one of the preceding claims, comprising:determining by the second train control system a position of the train,determining by the second train control system if the position of the train meets position criteria.

12. The method of claim 11 comprising determining by the second train control system, in response to a determination that the position of the train does meet the position criteria, whether the operating parameter is valid by reference to validity data.5 13. The method of claim 12, comprising determining by the second train control system, inresponse to a determination that the operating parameter is not valid, a further operating parameter for the train to travel along a further portion of the railway track.

14. A railway control system comprising a plurality of train control systems suitable for 10 location along a railway track, the railway control system being configured to perform the method of any one of claims 1 to 13.

15. A computer program comprising instructions, which, when executed by a railway control system causes the railway control system to carry out the method of any one of claims 1 to 13.1516. A computer-readable data carrier having the computer program of claim 15 stored thereon.

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