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The present invention relates to a railway control system, in particular, a railway control system in which a railway signalling system comprises trackside infrastructure operating under a first signalling protocol and a communication centre and communication apparatus adapted to communicate with the communication centre installed on at least one train operating on the railway under a second signalling protocol.
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The European Train Control System (ETCS) is the signalling and control component of the European Rail Traffic Management System (ERTMS). It is designed to replace the various legacy signalling systems in place across Europe, ensuring a common standard. In addition, it has been adopted as an option globally, and offers Positive Train Control (PTC) in various locations across the world. There are currently four numbered levels of ETCS, based upon the extent of cab-based signalling versus trackside equipment in the train control process. The levels are as follows:
Table 1: ETCS levels | Level | Description |
| 0 | ETCS compliant rolling stock does not interact with trackside equipment |
| NTC | ETCS-compliant train rolling stock is provided with additional Specific Transmission Modules (STM) to interact with legacy signalling systems under National Train Control (NTC) |
| 1 | ETCS trackside equipment is installed and spot transmission of data between trackside equipment and rolling stock via balises takes place |
| 2 | As level 1 but signalling information is provided by continuous transmission with a Radio Block Centre (RBC) via GSM-R (Global System for Mobile Communication - Railway), with balises used to detect train position |
| 3 | As level 2 but trackside equipment such as axle counters or track circuits is no longer relied upon |
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Level 1 is a cab-signalling system that is often superimposed on existing signalling systems. The balises are electronic beacons or transponders placed between the rails of the railway track that provide data as a train passes over via an uplink. A fixed balise is programmed to provide the same information to every train, and a programmable balise is used to transmit data to a train from a Lineside Electronic Unit (LEU) as part of ETCS Level 1 signalling control. Balises are installed in pairs so that the direction of travel can be indicated by the order in which the balises are detected.
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An ETCS signalling design specifies the locations in which the balises are installed. In a Level 1 system, the balise installation points are determined by the position of the existing signalling system, as indicated in Figure 1. Figure 1 is a schematic diagram of the interaction between an ETCS design and an existing signalling system. A railway track 1 comprises two rails 2 (of which one is shown) mounted on sleepers 3 resting on ballast 4. A signal 5 is provided at the start of a track section, along with an interlocking 6. A balise 7 is provided close to the signal 5. An approaching train 8 is provided with an ETCS receiver 9 and a GSM-R antenna 10. As the train 8 approaches the signal 5, the balise 7 provides details of its location and the state of the signal 5 based on interaction with the interlocking 6. As the train 8 passes though the signal 5 and over the train detection section boundary 11, the interlocking 6 detects the train movement and the aspect of the signal 5 is changed.
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Longer term, moving to an ETCS Level 2 signalling system, with or without trackside signals and/or ATO (Automatic Train Operation) is greatly desirable. The transition to a cab-based signalling system rather than a lineside-based signalling system brings significant benefits including improved safety, increased performance, reduced cost and lower environmental impact. However, the path to achieving a system that does not rely on lineside signalling is not clear. For example, moving to ETCS Level 2 requires the fitting of essential equipment into thousands of train cabs as well as training tens of thousands of train drivers. Although new trains can be fitted with the equipment or trains retrofitted with the equipment required, train drivers must refresh their training and knowledge regularly in order to maintain their competence in driving using such equipment.
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One solution to this issue is to overlay an ETCS system onto a legacy signalling system, such as NTC (National Train Control). Attempting to include ETCS capability in existing SSI and RRI interlockings comes with technical challenges due to the memory capacity and/or complexity of these systems. Although it is more likely that such functionality may be added into a more modern interlocking these account for a much smaller number of interlockings throughout the United Kingdom, for example, than the older SSI and RRI equipment. Providing ETCS functionality is typically done therefore by re-signalling the route to provide either ETCS alone or a combination of ETCS signalling and legacy signalling along the route, re-engineering the existing SSI (Solid State Interlocking) and RRI (Relay Interlocking) systems. The cost of re-signalling however may run into hundreds of millions of GBP and require a huge amount of time and resources depending upon the route(s) being re-signalled. Consequently, whilst this is the preferred solution for some routes, it may not always be possible to justify for every route in a move towards cab-based signalling. It also does not deal with the issue of re-equipping trains with the equipment required to communicate with a Radio Block Centre or with the need to train so many train drivers.
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The present invention aims to address these issues by providing a railway control system, comprising: a railway signalling system comprising trackside infrastructure adapted to operate under, and generate data using, a first signalling protocol; a communication centre adapted to operate under, and utilise data generated using, a second signalling protocol and store valid train routes; communication apparatus adapted to communicate with the communication centre installed on each train capable of utilising the second signalling protocol; an interface configured to link the trackside infrastructure to the communication centre, wherein the interface comprises an adapter configured to: collate and combine data received from the trackside infrastructure under the first signalling protocol; translate this collated and combined data into data under the second signalling protocol; and provide the collated, combined and translated data to the communication centre; wherein the communication centre is further adapted to check the collated, combined and translated data against the stored valid train routes, and, if check is successful, issue a movement authority to a train.
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By checking and converting data in one direction only, from the trackside infrastructure to the communication centre, the resources required to convert a legacy signalling and railway control system to an ETCS Level 2 system are greatly reduced compared with existing ETCS overlay approaches. Training of all drivers and upgrading of all existing rolling stock is not immediately required, as trains or drivers which are not able to use ETCS Level 2 can continue to use the first signalling protocol.
Preferably, the adapter is adapted to receive signal aspects, points states and trackside train detection states. Preferably, the adapter is realised in a CENELEC SIL 4 interlocking processor.
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Preferably, the communication centre is further adapted to not issue a movement authority if the check is unsuccessful, such that the railway control system is adapted to revert to using the first signalling protocol.
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Preferably, the trackside infrastructure comprises an interlocking. Preferably, the trackside infrastructure further comprises a front end processor adapted to feed data obtained from the trackside infrastructure to the interface.
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The interlocking may be an SSI interlocking, and the interface may be a network packet analyser to obtain data from a network data link connecting the interlocking to trackside equipment. wherein the trackside equipment comprises signals, points, trackside train detectors and lineside controllers.
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Alternatively, the interlocking may be a relay interlocking, and the interface may be a parallel input module in the CENELEC SIL 4 interlocking processor.
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Alternatively, the interlocking may be a computer-based interlocking, and the interface may be an I/O port in the front end processor.
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Preferably, the first signalling protocol is NTC and the second signalling protocol is ETCS Level 2.
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The present invention also provides a method of permitting a train to proceed along a route comprising a track section of a railway, comprising: at an adapter: receiving data from trackside infrastructure operating under a first signalling protocol; collating and combining the data and translating the collated combined data into data under the second signalling protocol; providing the collated, combined and translated data to a communication centre; at the communication centre: checking the collated, combined and translated data against stored valid rail routes; wherein if the check is successful, issuing a movement authority to a train; and if the check is unsuccessful, a movement authority is not issued and instead enabling the train to proceed under the first signalling protocol.
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The method may further comprise, if the check is unsuccessful and the train is already in motion towards the track section, issuing a stop command to the train prior to enabling the train to proceed under the first signalling protocol.
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The step of checking the data comprises preferably verifying the data against a state diagram, and the step of converting preferably comprises converting data in a first format compatible with the first signalling protocol to data in a second format compatible with the second signalling format.
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By checking and converting data in one direction only, from the trackside infrastructure to the communication centre, the resources required to convert a legacy signalling and railway control system to an ETCS Level 2 system are greatly reduced compared with existing ETCS overlay approaches. Training of all drivers and upgrading of all existing rolling stock is not immediately required, as trains or drivers which are not able to use ETCS Level 2 can continue to use the first signalling protocol.
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The present invention will now be described by way of example only and with reference to the accompanying drawings, in which:
- Figure 1 is a schematic diagram of the interaction between an ETCS design and an existing signalling system;
- Figure 2 is a schematic diagram of a railway control system in accordance with embodiments of the present invention;
- Figure 3 is a flowchart outlining a method in accordance with embodiments of the present invention;
- Figure 4 is a flowchart showing the data checking and conversion steps in a method in accordance with the embodiments of the present invention; and
- Figure 5 is a schematic signalling diagram illustrating the stages of employing embodiments of the present invention on a railway line.
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The present invention takes the approach that ETCS functionality does not need to be included in existing interlockings in order to provide a path to ETCS operation on existing and new routes on a railway. Instead, an adapter, hosted, for example, in a computer-based interlocking, such as a SIL Level 4 interlocking, can be used as a data converter to enable trackside infrastructure data in NTC track sections to be provided to a Radio Block Centre in order to check a route and issue a Movement Authority (MA) under ETCS Level 2 full supervision. The railway control system comprises a railway signalling system comprising trackside infrastructure adapted to operate under, and generate data using, a first signalling protocol, such as NTC. A communication centre adapted to operate under, and utilise data generated using, a second signalling protocol, such as ETCS, Level 2, as well as store valid train routes, is also provided. Communication apparatus adapted to communicate with the communication centre is installed on each train capable of utilising the second signalling protocol. The trackside infrastructure and the communication centre are linked by an interface that comprises an adapter configured to collate and combine data received from the trackside infrastructure under the first signalling protocol. The adapter then translates this collated and combined data into data under the second signalling protocol and provides this to the communication centre. The communication centre is further adapted to check the collated, combined and translated data against the stored valid routes. If the check is successful, the communication centre is able to issue a movement authority (MA) to the train.
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Figure 2 is a schematic diagram of a railway control system in accordance with embodiments of the present invention. The railway control system 20 comprises a railway signalling system 21 comprising trackside infrastructure 22 adapted to operate under, and generate data using, a first signalling protocol. In this example, the first signalling protocol is a legacy signalling system, such as NTC, which is used with various interlockings and is the existing train control system in use in countries such as the United Kingdom. The second signalling protocol is ETCS, preferably ETCS Level 2. The trackside infrastructure 21 comprises interlockings 23, which for simplicity are shown as a single interlocking in Figure 2, and will be described in the singular, however the principle illustrated should be understood to be applicable to multiple interlockings within a track section. As part of the infrastructure 22, other trackside equipment are included but not shown, such as signals, points, trackside train detectors and lineside controllers. The interlocking 23 is coupled to a Front End Processor (FEP) 24 and at least one trackside train detection processor 25. Trackside train detection includes axle counters and track circuits, which are used at the entry and exit of track sections. Both of the FEP 24 and trackside train detection processor 25 link to trackside equipment 26. As a train 27 enters a track section, the axle counter or track circuit detects the and counts the number of axles crossing into the track section, which is communicated by the trackside train detection processor 25 via a data link to the FEP 24. Similarly, when a train leaves the track section, a second axle counter detects and checks the number of axles, or activates a track circuit, which the trackside train detection processor 25 communicates to the FEP 24. The trackside train detection processor/FEP arrangement therefore acts to prove track vacancy, enabling the interlocking 23 to set points and signals as required for the next train 27 to enter the track section.
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An interface 28 is configured to link the trackside infrastructure 22 via the FEP 24 to a communication centre 29. Under ETCS, the communication centre 29 is a Radio Block Centre (RBC) or Radio Block Control, and whilst this is used in this example, it should be understood that the communications centre 29 may be any suitable control centre for rail signalling and management. The communication centre 29 also stores data relating to routes, and is able to check data against valid train routes when required, as described in more detail below. The interface 28 is a data link into an adapter 30, which is configured as a data checker and protocol converter to check the data output by the trackside infrastructure 22 and convert it to data to be input to the RBC 29. The adapter 30 is adapted to receive signal aspects, points states and trackside train detection states. Preferably, the adapter is realised in a CENELEC SIL 4 interlocking processor (in accordance with CENELEC standard EN50128). An example of a suitable processor is the Westrace Mk II available at www.siemens.com, which uses a 2-out-of-2 safety architecture for all modules and utilises existing trackside ethernet communication systems. The operation of the adapter 30 is discussed in more detail below.
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The adapter 30 enables the FEP 24 to communicate data gathered from the interlocking 23 to the communication centre 29. Firstly, the adapter 30 collates and combines the data received from the trackside infrastructure 22 under the first signalling protocol. This collated and combined data is then translated into data under the second signalling protocol and provided to the communication centre 29. Once this has happened, the RBC 29 checks the collated, combined and translated data, against its stored list of routes, and if correct will issue a Movement Authority (MA) to the train 27 to enable it to use the selected route and enter the appropriate track section. To enable the MA to be received by the train 27, the railway control system 20 further comprises communication apparatus 33 adapted to communicate with the RBC 29, installed on each train 27 capable of utilising the second signalling protocol. The communication apparatus 33 comprises a) radio, which sends and receives secure voice and data communications between railway operational staff, such as between the RBC 29 and the train 27.
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Consequently, if the data output by the trackside infrastructure 22 passes the data check by the RBC 29, the railway control system 20 utilises the second signalling protocol. However, if the data output by the trackside infrastructure 22 fails the data check by the RBC 29 or no data is converted or input to the RBC 29, the railway control system 20 utilises the first signalling protocol. If no data has been converted, no MA can be issued to the train 27 by the RBC 29, and the driver effectively has no instructions on how to operate under the second signalling protocol. The only option, therefore, at this juncture, is to issue a stop command to the train 27 and revert back to signalling procedures under the first signalling protocol. It may be preferable for the adapter 30 to issue an error message to the RBC 29 in the situation where data cannot be collated, combined and translated correctly, to enable the RBC 29 to issue a stop command immediately. As an alternative, the train driver is warned on approach to a track section that no MA has been received and therefore is trained to revert back to the first signalling protocol immediately and follow the trackside signals.
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In the case of an existing interlocking, such as a Westlock interlocking (available from www.siemens.com), the interface 28 is coupled to a port in the front end processor 24 of the interlocking 23 to obtain data. This may be done remotely, using an existing virtual I/O port, or by physically plugging in an ethernet connector that provides a specific link for the data into an I/O port already present in the interlocking. For a Westrace Mk II interlocking processor, this is done using a WNC or WNC+ I/O port. Within the railway network however, there are also other interlockings, including SSI and RRI systems. In an SSI system, the interface 28 may be a network packet analyser to obtain data from the trackside data link connecting the interlocking to other devices 26 such as signals, points and trackside train detection including axle counters and track circuits. The network packet analyser is able to eavesdrop onto the signals sent along the trackside data link in order to determine the relevant data. If an RRI system is being used, the interface 28 may be a parallel input module (PIM) connected to the adapter 30 to obtain data. The parallel input module is preferably present in the CENELEC SIL 4 interlocking processor forming the adapter 30.
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As outlined above, the adapter 30 is preferably realised within a CENELEC SIL 4 interlocking processor. The adapter 30 obtains data from the interlocking to trackside interface, comprising the status of all signals, trackside train detection and points. Hence the data checking and conversion is done against the same data that the signaller has at their disposal, as will now be described.
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Figure 3 is a flowchart outlining a method in accordance with embodiments of the present invention. The method 300 permits a train 27 to proceed along a route comprising a track section of a railway. At step 302, an indication that permission for a train 27 to proceed is required is obtained. This is done by receiving data from trackside infrastructure 22 operating under a first signalling protocol, which in this example, is NTC, but may be any other legacy train control system. At step 304, the data is collated, combined and translated into a second signalling protocol. At step 306 the collated, combined and translated data is input to an RBC 29, and checked against the valid train routes held by RBC 29. If the check is correct, a movement authority is issued to the train 27 to proceed under the second signalling protocol, which in this example, is ETCS Level 2. If the data fails the check at step 306, a movement authority is not issued at step 308, and at step 310 the train 27 is enabled to proceed under the first signalling protocol. If the train 27 is already in motion towards the track section, then at step 312 a stop command is issued to the train 27 prior to enabling the train 27 to proceed under the first signalling protocol. The checking and conversion steps are outlined in greater detail in Figure 4.
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Figure 4 is a flowchart showing the data checking and conversion steps in a method in accordance with the embodiments of the present invention. At step 304 (From Figure 3) the first step 402 is to collate and combine the data that has been received from the trackside infrastructure 22. Then, at step 404, this collated and combined data is translated into data under the second signalling protocol. This is done by enabling the adapter 30 to act as a protocol converter, based on an internal/external slave and database model. Preferably, the step of converting comprises converting data in a first format compatible with the first signalling protocol to data in a second format compatible with the second signalling format. At step 406 the collated, combined and translated data is provided to the RBC 29. Since the RBC 29 stores the details of valid train routes a check on the collated, combined and translated data is run against these stored valid train routes to determine if a movement authority can be issued to a train. This is done at step 408. The checking is preferably done using a finite state machine verification approach, where individual valid train routes are represented as processes in a state diagram and the collated, combined and translated data is verified against this state diagram. The route data may be represented, for example, using a state/event table, UML (Unified Modelling Language) descriptors or SDL (Specification and Description Language) descriptors. The checking may alternatively be done by using graphical representation systems, with the valid train route data represented as nodes within a graph rather than as a state diagram. If the check is successful, the method reverts to step 308 above and a movement authority is issued.
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However, if the check is not successful, three alternative events may occur. The first, at step 410, is that an error message is issued to the RBC 29 and the RBC then sends a stop command by reverting to step 312 above to the train 27. The second, at step 412, is that the process reverts to step 310 above, and the train is enabled to proceed under the first signalling protocol. The third is that nothing is sent to the train 27 by the RBC 29, and as the train approaches the track section a warning is given to the driver by the on-board train systems at step 414 that no movement authority has been received. The result of both of these possibilities is that the train driver reverts to using the first signalling protocol.
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In typical ETCS conversion schemes, much of the engineering resource is tied up in providing a two-way synchronisation between the interlocking and the RBC, wherein each system is always in full agreement in terms of routes and authorities with the other. This requires engineering changes at the level of the trackside infrastructure, with re-signalling interlockings that either do not have sufficient memory or operational capacity, or are too complex for the inclusion of ETCS functionality within the interlocking itself easily. In the embodiments of the present invention, the RBC 29 is only ever a follower of the interlocking 23, since there is no facility for the RBC 29 to send data back to the interlocking 23 via the adapter 30 or interface 29, only for data to be sent to the RBC 29 from the interlocking 23 via the interface 29 and adapter 30. This results in the train 27 running in full supervision mode, with all train and track data being available on board. When no movement authority is sent by the RBC 29, this data is not available on board the train 27, and thus the railway control system reverts back to using lineside signals under the legacy system - the first signalling protocol.
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Not only, therefore, do the embodiments of the present invention offer a fallback to a legacy signalling system when ETCS is not available due to a fault, it is also possible to run trains using the legacy signalling system and trains employing ETCS along the same routes. This reduces the need to retrofit ETCS on-board equipment into existing rolling stock, and the amount of driver training required if older rolling stock with only legacy signalling working capabilities are still in use.
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Figure 5 is a schematic signalling diagram illustrating the stages of employing embodiments of the present invention on a railway line. Figure (i) shows the stations and junctions on a main railway line 50. A, B, C, D are stations at which all train services call, with E being a station with a limited daily service. Various railway lines to other destinations a, b, c, d, e, f, g, h served by services from the stations A, B, C, D on the main railway line 50 are also shown, and may have a station on the main railway line 50 as a terminus, such as station E and destination e, or use branch lines to and from a station or the main railway line 50, such as destination c. The main railway line 50 is divided into three track sections 51, 52, 53, and in this example, the legacy signalling system NTC is served mainly by relay interlockings RRI. However, three sections 54 use computer-based interlockings CBI within the overall RRI signalling scheme.
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Figure (ii) shows a first stage in upgrading the main railway line 50 to ETCS Level 2. Initially, the first track section 51 and the line to destination d are provided with the railway control system 20, 55 of Figure 2. For the first track section 51, the RRI are upgraded by installing a CENELEC SIL 4 interlocking processor and using a parallel input module in the CENELEC SIL 4 interlocking processor as the interface 28. For the line to destination d, an SSI interlocking is upgraded again by installing a CENELEC SIL 4 interlocking processor along with a network packet analyser to obtain data from a trackside data link connecting the SSI to trackside devices 22 as the interface 28 to the CENELC SIL 4 interlocking processor. In both upgrades, a new cabinet containing the CENELC SIL 4 interlocking processor is installed at the interlockings, and connected as required. The CENELC SIL 4 interlocking processor is connected to the local ethernet present at the interlockings in order to communicate with the RBC 29. Such an installation would be easily included in a Signalling Equipment Room.
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Figure (iii) shows a final stage in upgrading the main railway line 50 to ETCS Level 2. Here all of the RRI in the three track sections 51, 52, 53 have been upgraded using a CENELEC SIL 4 interlocking processor and using a parallel input module in the CENELEC SIL 4 interlocking processor as the interface 28. In addition, in the CBI sections 54, I/O ports in the front end processors of the interlockings have been utilised as the interface 28, and a small section 56 of line has been fully re-signalled to achieve ETCS Level 2 compliance for operational reasons. As above, a cabinet including the CENELC SIL 4 interlocking processor is installed for each interlocking or for a group of interlockings, depending on location, with minimal lineside engineering requirements. As a result of this, the entire main railway line 50 from stations A to D is now ETCS Level 2 compliant, without any major infrastructure work, and offers the fallback position that should the ETCS Level 2 control fail, the legacy signalling system, such as NTC, may be used instead.