EP2168840A1

EP2168840A1 - Method for operating a train on a railway system, in particular comprising a national ATP infill in ETCS

Info

Publication number: EP2168840A1
Application number: EP08017159A
Authority: EP
Inventors: Georg Dr. Karner
Original assignee: Thales Security Solutions and Services GmbH
Current assignee: Thales Security Solutions and Services GmbH
Priority date: 2008-09-30
Filing date: 2008-09-30
Publication date: 2010-03-31
Anticipated expiration: 2028-09-30
Also published as: EP2168840B1; ATE517012T1

Abstract

The invention relates to a method for operating a train (11) on a railway system (1), wherein the railway system (1) is equipped both with a train protection system with non-continuous information transfer, such as level 1 ETCS, and a target speed information system with a continuous information transfer, such as a national ATP system. The target speed information system is used to update the track profile information of the train protection system between information transfer points, such as balise groups (4a, 6a, 7a), by replacing checkpoint speeds of the track profile information with target speeds. However, the track profile information is not altered in other ways by the replacement; in particular there is no re-calculation of a track profile information by the on-board-unit (11a) of the train (11) for safety reasons. In order to be able to use the updated checkpoint speeds, the train (11) receives track profile information also for track section parts (13) adjacent and beyond the last forthcoming checkpoint with a corresponding red railway signal, and the setting of track elements, such as switches (2), in said track section part are assumed to allow the highest possible speed when transmitted to the train (11). A safe train speed is guaranteed by the proper choice of the target speeds. The target speed is provided by the existing target speed information system, without an intervention into it. The invention improves the train traffic flow on the railway system.

Description

The invention relates to a method for operating a train on a railway system, - wherein a train protection system provides to the train a track profile information about a forthcoming track section, wherein the track profile information comprises a speed profile information for the entire forthcoming track section, location of checkpoints within the forthcoming track section and a checkpoint speed information for the last checkpoint within the forthcoming track section, wherein track profile information is provided non-continuously to an on-board-unit of the train at discrete information transfer points of the railway system upon bypassing of the train, wherein the on-board-unit enforces a maximum train speed according to the track profile information, - wherein a target speed information system provides to the train a target speed information, valid for the next checkpoint of the forthcoming track,
wherein the target speed information is provided to the train continuously.
When operating a train on a railway system (i.e. basically a network of railway tracks), the traffic situation on the forthcoming railway tracks must be taken into account for making operating decisions, such as choosing the train speed, a delay time at a station, etc. Usually, a train driver makes these operating decisions, based on, in particular, his knowledge of the forthcoming railway tracks, the setting of railway signals, and a time-table.
However, in modern railway systems, the train driver is supported by electronic systems, which help to optimize the train operation. The most important goal of these supporting electronic systems is an increased train safety, and often also a minimization of travelling times between stations or energy conservation. The train driver and typically also an on-board-unit on the train are, during travelling, supplied with up-to-date information about the traffic situation well before the moment the train driver could get the same information by looking out of the front window of the train. For example, as long as a driver cannot see a railway signal, he must assume it might be in the "stop" setting ("red signal") and approach it carefully, i.e. slowly, in order to be able to stop the train in time. When the driver is supported by electronic systems, in contrast, railway signals in the "proceed" setting ("green" signal) can be taken into account before the driver can see the shining of the corresponding signal lamp and approach with higher speed. In this way, the train operation can be handled in a more anticipatory way, typically by applying an electronic on-board-unit which translates the incoming information in train operation procedures.
A first type of supporting electronic system is here referred to as a "target speed information system". This system (quasi) continuously transmits a "target speed information", i.e. a train speed the train is supposed to stick to when passing a next "checkpoint" on the forthcoming track. Typically, said checkpoint is linked to a railway signal. At in principle any time during approaching the checkpoint, the target speed information can be updated on the train, and the train driver of the on-board-unit may react accordingly. However, with such a system the driver may only be supported in a rather selective way. Examples for such systems are local or national ATP (automated train protection) systems.
A second type of supporting electronic system is here referred to as a "train protection system". In this system, the on-board-unit on the train is supplied non-continuously with track profile information about a forthcoming track section. Note that said forthcoming train section typically does not cover the entire remaining tracks the train is scheduled to drive, but only an adjacent fraction of them. The track profile information includes, above all, a speed profile information and checkpoint speeds (see below). The track profile information is supplied at discrete information transfer points distributed along the tracks, such as balise groups. The information transfer points are typically separated by about 1000 metres. When the train has passed the known track section as described in the last track profile information, it must be supplied with the track profile information of the next forthcoming track section at a next information transfer point. A well known train protection system of this type is the level 1 ETCS (ETCS: European train control system).
The track profile information is rather extensive, and comprises speed profile information, i.e. appropriate train speeds as a function of the location, taking into account the terrain, and further checkpoint speeds, i.e. maximum speeds that must be obeyed when passing specific locations, such as locations of railway signals and switches. By means of the track profile information, the on-board unit can propose resp. enforce train operation procedures in a relatively broad extent.
However, since the track profile information is only transferred in a non-continuous matter, there is the possibility that the track profile information becomes outdated before the train arrives at the next information transfer point where it could be updated. Using outdated track profile information disturbs the train operation and, in particular, may lead to unnecessary delays.
More specifically, let us assume that a train approaches a checkpoint related to a railway signal, which protects a railway switch, and the train has passed the last information transfer point before said checkpoint already. When the train was passing said last information transfer point, the checkpoint had a checkpoint speed "zero" (i.e. the train must stop at a "red" railway signal), and a corresponding track profile information has been transferred to the on-board-unit of the train. However, let us further assume that after the train has passed the last information transfer point already, the railway signal switches to "pass" and accordingly to a "non-zero" checkpoint speed (e.g. the preceding train has left the area of the protected railway switch). Then the train will not be able to receive this new information on time. According to the most recent track profile information known by the on-board-unit, the train will slow down and stop at the railway signal. Only after having received updated track profile information, which is typically provided at the railway signal the train stopped at, the train may reaccelerate and pass the railway signal.

Object of the invention

It is therefore the object of the invention to improve the train operation on a railway system when using a non-continuous train protection system, and in particular to avoid unnecessary delays.

Short description of the invention

This object is achieved, in accordance with the invention, by the method as specified in claim 1.
When operating a train on a railway system equipped with a non-continuous train protection system, during the time a train travels between the discrete information transfer points, it is unavailable for the train protection system. Often, the railway system is already equipped with (or may, at relatively low costs, be equipped with) a continuous target speed information system. The continuous target speed information may be used for filling in the times of unavailability of the train in the non-continuous train protection system, in order to update checkpoint speeds. This is useful when the traffic situation changes during the times of unavailability, e.g. if a preceding train has cleared a track.
Additionally, the inventive method also provides that a checkpoint speed increased by an inventive infill can actually be used in agreement with the stored track profile of the on-board unit. Typically, when a track profile information comprises a "zero" checkpoint speed, the track profile information basically ends with the corresponding (last) checkpoint; further information would be of no relevance, since the train has to stop anyway and may collect further track profile information at the information transfer point of the checkpoint. In contrast to that, according to the present invention, the track profile information also covers a track section part adjacent and beyond this checkpoint. In this situation, the straightforward approach for providing a track profile information extending beyond the checkpoint would be to assume the most restrictive setting of possible track elements beyond the checkpoint, to achieve guaranteed train safety. The profile related to the assumed most restrictive setting would cause a braking of the train.
In contrast to that, the inventive method arranges for altering the track profile information in the track section part beyond the checkpoint, in order to allow the full use of the checkpoint speed increased by the target speed information infill. Typically, said track section part (which is safeguarded by the checkpoint) comprises a track element with different possible speed limits (such as a switch comprising a setting "straightforward" with a high speed limit, and a setting "turn" with a low speed limit). In this situation, according to the invention, the track profile information provided to the on-board-unit is based on the setting of the highest speed limit, no matter what the actual setting is at the point of time the train passes the information transfer point. The reason for this is that if the on-board-unit assumed a setting with a low speed limit, the train speed at the checkpoint would not be limited by the checkpoint speed (increased by infill with the target speed), but by the low speed limit at the subsequent track element according to the track profile information, which is taken into account when the train speed is controlled by the on-board-unit in an anticipatory way. By means of the invention, it is actually the checkpoint speed increased by infill with the target speed which limits the train speed at the checkpoint, since the track profile information assumes a high speed limit at the track element.
In order to ensure the safe train operation under these conditions, the target speed information system, according to the invention, has to indicate a target speed for the checkpoint which takes into account the current setting at the subsequent track element. The checkpoint assigned to (i.e. preceding) the track element safe-guards the track-element (i.e. the train's passing of the track element). In other words, if the actual current setting of the subsequent track element requires a low train speed, the target speed indicated is correspondingly equally low. In contrast, if the actual current setting of the subsequent track element allows a high train speed, the target speed indicated is correspondingly equally high.
As an example, assume that a train enters a station from the double-track main line with permitted speed of 120 km/h where it is scheduled to stop. The information transmitted to the train at the entry signal announces the exit signal as showing "stop". Assume further that a switch located beyond the exit signal allows a speed limit of 40 km/h when positioned for a change of tracks and that the main line beyond the station allows 80km/h, e.g. due to tight curves. The inventive track profile information transmitted to the train will contain the 80 km/h limit but not the 40 km/h. Thus when the exit signal switches to "proceed with line speed", the onboard unit will allow to accelerate the train to 80 km/h. In case the train is a rather short one (therefore having a good acceleration), and in case the scheduled stop point was several hundred metres in rear of (before) the exit signal, then the train will considerably exceed 40 km/h when passing the exit signal. This shows the intended performance gain.
Further, the invention prescribes an update of the track profile information for the on-board-unit at an information transfer point assigned to (i.e. located at or in the vicinity of) the last checkpoint, so the artificially altered track profile information is used only for approaching and the immediate passing of the checkpoint with the checkpoint speed in accordance with the normal operation of the on-board-unit. When the train passes the checkpoint and its respective information transfer point, the on-board-unit receives new track profile information, with accurate information about the forthcoming track element.
It should be mentioned that in accordance with the invention, during approaching of the last checkpoint after having passed the last information transfer point before the last checkpoint ("final approach"), the target speed information may change multiple times and the checkpoint speed may be "filled in" accordingly ("multiple consecutive upgrades"). However, note that typically the target speed is only increased in this way (such as from 0 km/h to 40 km/h to MAX), for safety reasons.
Note that the track profile information considers information about current settings of signals and track elements, such as switches, as well as fixed track profiles, such as curves, and gradient profiles of the forthcoming track section. The target speed information system considers information about current settings of signals and track elements on the forthcoming track section only. The track section part, which is adjacent and beyond the last checkpoint, typically extends until the next checkpoint (though this next checkpoint is not considered part of the track profile information). The track element is close enough to the checkpoint such that the lowest of the possible speed limits of the track element may limit the train speed already at the checkpoint. Typically a checkpoint is assigned to a railway signal. The last checkpoint is defined as the checkpoint in the travelling direction of the train which is farthest away within the forthcoming track section covered by the track profile information.

Preferred variants of the invention

A preferred variant ("initial checkpoint speed non-zero") of the inventive method is characterized in

that the track profile information covers a track section part adjacent and beyond said last checkpoint, independent of the checkpoint speed information,
that in case the latter track section part comprises a track element with different possible speed limits, wherein the speed limit depends on the current setting of the track element, the speed profile information provided to the on-board-unit belongs to the setting of the track element with the highest of the possible speed limits, independent of the actual setting of the track element,
and that in case the target speed information for said last checkpoint indicates a higher speed than the checkpoint speed information, then the on-board-unit allows the train to approach and pass said last checkpoint as if the checkpoint speed information according to the track profile information was indicating said higher speed, and obtains an update of the track profile information at a discrete information transfer point assigned to said checkpoint. This further improves the flow of train traffic on the railway system. The information that an increased train speed at the track element - and therefore also at the corresponding (preceding) checkpoint - has become possible can be used (i.e. upgraded to) during the train's final approach also if the initial checkpoint speed information was non-zero. So an unnecessary slow passing of the checkpoint can be avoided. Note that again, a faked setting of the track element is forehandedly communicated to the on-board-unit. In a variant of the above example, assume that the entry signal (resp. a corresponding information transfer point) transmits the track profile information "change tracks after the exit signal" which includes a speed limit of 40 km/h valid after the exit signal. While the train is at standstill, the station master decides to allow the train to continue without changing tracks. This means that the exit signal goes to stop (Such change is safe because the concerned train is at standstill). The target speed information system transmits this information to the train. Then the switch is re-positioned and the exit signal goes to "proceed" again, this time without a speed limit. Again this information is transmitted to the onboard unit by means of the target speed information system. If the track profile information has been prepared according to the invention, the train can fully accelerate without having to stick to the 40 km/h limit announced at the entry signal.
In a further variant of the inventive method, the track profile information always contains exactly one checkpoint. In this variant, the target speed information can directly be correlated to the only checkpoint, simplifying the processing of the target speed information and its use in the on-board-unit. Note that an appropriate (high) checkpoint speed allows sufficient system performance while conserving safety. In ETCS terms,
The standard ETCS infill mechanisms must be avoided as the OBS (on board system / on board unit) always converts an infill MA (MA=movement authority) to a 2-section MA.
gradient profile and SSP (= Static Speed Profile) must cover all sections up to the intended stop point, plus one extra section in case V_LOA = 0 (V_LOA= speed at the end of movement authority)
section borders are located exactly at all main signals

Example: Assume that

- the line speed is 160 km/h
- 2 sections suffice to brake the train to standstill from 160 km/h
- 1 section suffices for braking from 120 km/h
When the information available at a signal's transmission point suffices to give a 3-section MA a 1-section MA with V_LOA = 160 km/h and 3 sections gradient profile and SSP are transmitted to the train. In place of a 2-section MA, a 1-section MA with V_LOA = 120 km/h and 2 sections gradient profile and SSP are transmitted. A 1-section MA is handled according to claim 1, i.e. gradient profile and SSP are given for 2 sections, with the inventive improvements applied.
Note: an improvement of this method along the lines of claim 2 is also possible.
In another variant of the inventive method, the target speed information system may transmit the special value "no speed limit", and the on-board-unit supervises a fixed speed limit in such a case. Said special value "no speed limit" is also referred to as "MAX". The fixed speed limit may be a general maximum train speed valid throughout the entire railway system, such as 160 km/h. Alternatively, the fixed speed limit may be derived from general assumptions about required/guaranteed brake performance of the train. For example, supervising a checkpoint speed of 120 km/h will always guarantee that the train can be stopped in rear of the checkpoint following the one for which 120 km/h is supervised.
In a highly preferred variant, the location of the last checkpoint corresponds to a position of a railway signal. Typically, in accordance with the invention, all railway signals or at least the main railway signals are safe-guarded by checkpoints.
Further, in a highly preferred variant of the inventive method, the information transfer points comprise balise groups. With balise groups, information can be transferred in a reliable way with a ground-based system.
Further, in a preferred variant of the invention, the track element comprises a switch. Switches are very common in railway systems and typically have different speed limits in dependence of their setting (straightforward or turn).

Note that other track elements, such as railway crossings, may be handled by means of the invention, too.
Another variant of the inventive method is characterized in that information transfer points are provided on the railway system at least at all signals. By this means, trains may collect new track profile information at all signals, in particular when having to stop at a railway signal. Note that preferably checkpoints are also provided at (assigned to) at least all signals. Further note that preferably information transfer points are provided on the railway system at least at all checkpoints.
In a highly preferred variant, the train protection system is a level 1 ETCS system. Existing installed level 1 ETCS systems can easily be prepared for use with the inventive method. Note that in this variant, the checkpoint speed is "V_LOA" and checkpoints are ETCS section borders (or railway signals). The track profile description (information) comprises at least a gradient profile and a static speed profile, both extending beyond the EOA/LOA.
Equally highly preferred is a variant wherein the target speed limit information provided by the target speed information system originates from a local or national automatic train protection (=ATP) system. Existing ATP systems can easily be prepared for use with the inventive method.
In another advantageous variant, the target speed information is provided to the train by means of current pulses between the two rails the train travels on. This is a simple and reliable way for continuously providing target speed information to a running train. Current pulses have been proved in practice in national ATP systems.
A further variant of the inventive method is characterized in that that in case the on-board-unit wants to use a target speed for replacing a checkpoint speed, the train driver is requested to acknowledge said procedure before the on-board-unit allows the train to approach and pass the checkpoint using said target speed as the checkpoint speed. This variant improves the train safety. The train driver should have the possibility to do - and should actually do - a visual check on the checkpoint in question (which is typically a signal) before doing the acknowledgement. In case the visible checkpoint (signal) also indicates the allowed passing speed, the driver should also check and acknowledge the correct speed limit, i.e. the target speed information.
In a highly preferred variant, the provided track profile information defines "forbidden areas" of the forthcoming track section, with the on-board-unit not being allowed to accept target speed information for use in replacing a checkpoint speed when the train is within a forbidden area. Forbidden areas are used to deny checkpoint speed replacements under unsafe circumstances, e.g. if there is a high danger of erroneous information transfer to the train, or if the attribution to the correct checkpoint is unclear (e.g. if the train is close to an insulation / track circuit boundary) or if the train is already too close to a peril point of the railway system. Note that a forbidden area adjacent and beyond a checkpoint, such as F2 in Fig. 1b, is typically established when the quality of transmission of the target speed information is expected to be bad due to the railway track construction (such as at switches).
In a further development of this variant, a forbidden area extends adjacent and before a checkpoint, see for example F1 in Fig. 1b. The latter further development is used in particular when the on board unit possibly would allocate the target speed to an incorrect checkpoint. Note that the checkpoint to which the forbidden area extends adjacent and before is typically the last checkpoint within the forthcoming track section.
Also within the scope of the invention is a tool, in particular software program, for reading out a track profile information of a forthcoming railway track section of a train from a database, and for delivering the read out track profile information to a discrete information transfer point of a train protection system,
wherein the track profile information comprises a speed profile information for the entire forthcoming track section and a checkpoint speed information for a last checkpoint within the forthcoming track section,
wherein in case the checkpoint speed according to the checkpoint speed information is "zero", the track profile information covers a track section part adjacent and beyond said last checkpoint,
wherein the tool is designed such that in case said track section part comprises a track element with different possible speed limits, wherein the speed limit depends on the current setting of the track element, the read out speed profile information delivered to the information transfer point belongs to the setting of the track element with the highest of the possible speed limits, independent of the actual setting of the track element. The inventive tool is used to provide a track profile information to an on-board-unit of a train in accordance with the invention, namely with a track profile information extending beyond the next stop signal and altered with respect to the actual traffic situation as saved in the database. By means of the inventive tool, the inventive method can be realized as far as the track side is concerned.
In a preferred embodiment of this tool, the read out and delivered track profile information also covers a track section part adjacent and beyond said last checkpoint when the checkpoint speed according to the checkpoint speed information is "non-zero". This adapts the tool for improving the train traffic also in case of non-zero scheduled checkpoint speeds.
Also within the scope of the present invention is the use of an on-board unit of a train in an inventive method as described above, characterized in that the on-board-unit enforces a maximum train speed according to a stored track profile information about a forthcoming railway track section, wherein the track profile information comprises a speed profile information for the entire forthcoming track section, location of checkpoints within the forthcoming track section and a checkpoint speed information for the last checkpoint within the forthcoming track section,
wherein the on-board-unit comprises means for receiving track profile information upon passing of discrete information transfer points,
wherein the on-board-unit comprises means for enforcing a maximum train speed according to the track profile information,
wherein the on-board-unit has an input for continuously inputting a target speed information of for the train, valid for a next checkpoint of the forthcoming track,
wherein the on-board-unit is designed to allow the train to approach and pass the last checkpoint of the stored track profile information as if the checkpoint speed was indicating the speed according to the target speed information, which is higher than the checkpoint speed, provided that

the on-board-unit has received a target speed information with respect to the last checkpoint,
and the stored track profile information about the forthcoming railway track section also covers a track section part adjacent and beyond said checkpoint. By means of the inventive use of the on-board-unit, the inventive method of train operation can be realized as far as the train is concerned.
Also in accordance with the invention is the use of an on-board unit of a train in a method according to claim 3, characterized in that the on-board-unit enforces a maximum train speed according to a stored track profile information about a forthcoming railway track section, wherein the track profile information comprises a speed profile information for the entire forthcoming track section, location of a checkpoint within the forthcoming track section and a checkpoint speed information for the checkpoint within the forthcoming track section,

the on-board-unit has received a target speed information,
and the stored track profile information about the forthcoming railway track section also covers a track section part adjacent and beyond said checkpoint. In this use variant, an allocation of the checkpoint speed to ETCS sections can be avoided.
Note that when there is more than one checkpoint in a track profile of a forthcoming track section, the expressly given checkpoint speed always refers to the last checkpoint. (Note that separate auxiliary checkpoint speeds may be assigned to previous checkpoints, though; if no separate auxiliary checkpoint speeds are assigned, this is equivalent to implicitly assigning "unlimited"/"infinite" speed ("no speed limit") to all other (previous) checkpoints within the track profile so that the target speed information can never deliver less restrictive information for these checkpoints).
Further advantages can be extracted from the description and the enclosed drawing. The features mentioned above and below can be used in accordance with the invention either individually or collectively in any combination. The embodiments mentioned are not to be understood as exhaustive enumeration but rather have exemplary character for the description of the invention.

Drawing

The invention is shown in the drawing.

Fig. 1a: shows schematically a railway system on which a train is operated by means of the inventive method, at a first train position
Fig 1b: shows the railway system of Fig. 1a, at a later second train position.

The invention describes a method for operating a train on a railway system, at which are installed both a

- train protection system with non-continuous information transfer, and a
- target speed information system with a (quasi) continuous information transfer. By means of the invention, both systems are used in combination. However, the inventive method proposes a few alterations to the way the train protection system is used, in order to achieve an optimized train traffic flow.

In the following, the invention is described by way of example, wherein, in accordance with the invention, the train protection system is a level 1 ETCS system, and the target speed information system is a national ATP system.
A railway system 1 for use with the invention is illustrated schematically in Fig. 1a ; note that the figure can only illustrate a part of the railway system. The railway system 1 comprises, in particular, a plurality of tracks (see the paired rails 15 in the figure), a switch 2, a railway crossing 14, railway signals 4, 5, 6, 7 and balise groups 4a, 6a, 7a. Further, along the tracks of the railway system 1, checkpoints CP4, CP5, CP6, CP7 are defined, all of which correspond to the location of railway signals, namely signals 4, 5, 6, and 7.
On the railway system 1, a train 11 is operated. The train 11 has a general movement direction from left to right (see arrow). To help the train conductor drive the train 11, and in particular to have efficient accelerating and braking, the train 11 comprises an on-board-unit 11a which can collect track profile information from balise groups 4a, 6a, 7a it bypasses. The on-board-unit 11a basically enforces maximum speeds, typically derived from a speed profile. The track profile information covers a forthcoming track section the train 11 is intended to travel on. However, between balise groups (such as between balise groups 4a and 6a), the track profile information cannot be updated.
In the example shown in Fig. 1a, the train 11 has just received track profile information from balise group 4a, and said track profile information covers a forthcoming track section marked with TS1, basically extending from balise group 4a until some distance beyond switch 2.
The track profile information TS1 includes here a speed profile information for the forthcoming track section TS1, information about the location of the checkpoints CP5 and CP6, as well as a checkpoint speed information for the last checkpoint CP6 of the forthcoming track section TS1. In the example shown in Fig. 1a, the checkpoint speed for checkpoint CP6 is "zero", i.e. the train 11 is scheduled to stop at the "red" railway signal 6 (recognizable by the lowered signal bar) - there is still a train 12 on the track section beyond railway signal 6 the switch 2 targets at in its current "turn" setting. The speed profile information also includes a speed limit for the area of the switch 2, wherein the setting of the switch 2 (straightforward or turn) influences the allowable maximum speed there. Since the switch 2 is currently in the "turn" setting, the advocated local speed limit is rather restrictive at 40 km/h (however, for the transmitted track profile information for the switch 2 see below). Although the "movement authority" for the train 11 ends at (red) railway signal 6, the track profile information for track section TS1 includes a track section part 13 (including switch 2) adjacent and beyond the last checkpoint CP6 (here extending up to but excluding checkpoint CP7), in accordance with the invention.
The balise groups 4a, 6a, 7a each are attached to a tool 4b, 6b, 7b (such as a computer program run on a computer), which in turn is connected to a data base 8 which has stored data about the actual current traffic situation, and on the geography of the railway system 1. Note that the data base 8 does not necessarily have a central storage device containing all information about the railway system 1, with said central storage device being accessed by all tools 4b, 6b, 7b. It is sufficient that the database 8 provides that each tool 4b, 6b, 7b has access to a small portion of all information, namely the portion relevant for its respective track section; for the latter purpose, the database 8 may consist of a number of local storage devices, each containing information only for one or a few tools 4b 6b, 7b (not shown). The tools 4b, 6b, 7b extract information from the database 8 and prepare the track profile information for the respective balise groups 4a, 6a, 7a which act as information transfer points of the level 1 ETCS.
Further, through the metal rails 15 of the railway system 1, namely isolated bars, electric pulses may be sent to the travelling (or still-standing) train 11 in order to allow a simple information transfer (the electric circuits are not shown in Figs. 1a, 1b). Here the national ATP system sends information about the target speed at the next checkpoint, e.g. by indicating one of a limited number of possible target speeds, such as "zero" (0 km/h), 40 km/h, 80km/h, 120 km/h and MAX). I.e. between railway signal 4 resp. checkpoint CP4 and railway signal 5 resp. checkpoint CP5, the train 11 receives the target speed information for the checkpoint CP5; further between railway signal 5 resp. checkpoint CP5 and railway signal 6 resp. checkpoint CP6, the train 11 receives target speed information for checkpoint 6 (and so on). Typically, it is the on-board-unit 11a which will receive and analyse the target speed information on the train 11.
According to the inventive method of train operation,

- the balise groups may transmit a track profile information which is specifically altered in view of the actual setting of the railway system 1 at the point of time it is transmitted, and
- the on-board-unit may replace a checkpoint speed by a target speed information in specific circumstances.

When train 11 passes the balise group 4a, railway signal 6 is red (indicating stop), and switch 2 is in a turn setting allowing only low passing speed of 40 km/h (see Fig. 1a). This corresponds to a track profile information with a checkpoint speed (which refers to the last checkpoint CP6 of TS1) of "zero", and a speed limit for the switch 2 of 40 km/h in the turn setting, which is present in the database 8 at that point of time. However, in accordance with the invention, the track profile information transmitted to the train 11 by the balise group 4a, in accordance with the invention, comprises a speed limit for switch 2 of 120 km/h in the straightforward setting; the checkpoint speed is still "zero" though. The deviation in the track profile information as compared to the data base 8 is established by means of the inventive tool 4b. Note that the inventive tool 4b does not need access to the information about the current setting of the switch 2 by means of the database 8, since the transmitted track profile information is independent of the current switch setting.
In case the signal 6 remains "red" during the further approach of the train, then the target speed information transmitted to the train between checkpoints CP5 and CP6 would be and remain "zero", too. As a result, the checkpoint speed of the track profile information would also remain "zero", and the train would safely stop at railway signal 6.
In contrast thereto, let us now assume that during the further approach of the train to signal 6, e.g. when the train 11 has just passed railway crossing 14, railway signal 6 has changed to "pass", and the switch 2 has changed into "straightforward" setting which would allow a high passing speed of 120 km/h, compare Fig. 1b . Then, there is no more need for the train 11 to stop at railway signal 6. In this case, the target speed information is transmitted to the train between checkpoints CP5 and CP6 with a target speed value of 120 km/h. The latter value indicates both that the signal 6 has switched to "pass", and that the adequate speed at the (last) checkpoint CP6 may be chosen as 120 km/h since the subsequent switch 2 is in a setting allowing such a high speed. In this situation, according with the invention, the on-board-unit 11a of the train 11 is allowed to replace the original checkpoint speed of "zero" of the stored track profile information with the target speed, here 120 km/h ("infill" or "upgrade"). Since the stored track profile information further assumes a straightforward setting of the switch 2 allowing also 120 km/h, the speed limit of the switch 2 (as the subsequent track element protected by the checkpoint CP6) does not limit the train speed at the checkpoint CP6. Note that in case the track profile information assumed the original speed limit of 40 km/h for a "turn" setting at the switch 2, the train speed would be limited to about 40 km/h at the preceding checkpoint CP6, too, in order to be able to obey the speed limit at the switch 2 which is very close to the checkpoint CP6 as compared to the braking distance of the train 11. Further note that in case no track profile information was available for the track section part 13 at all, the on-board-unit 11a could not supervise the train speed near and beyond the checkpoint CP6 properly. This shows the usefulness of the manipulation of the track profile information as transmitted to the train for improving the flow of the train traffic.
If during the train's approach only the signal 6 had switched to "pass", but the switch 2 remained in the "turn" setting allowing only 40 km/h, then the target speed information transferred to the train between checkpoints CP5 and CP6 would be 40 km/h. The checkpoint speed would be updated from "zero" to 40 km/h only, and the train would slow down and pass the railway signal with 40 km/h.
In all the three above mentioned cases, when stopping at or passing the railway signal 6, the train also passes the associated balise group 6a, which updates the track profile information to the next forthcoming track section TS2 (including at least checkpoint CP7 and extending beyond it). In track section TS2, the switch 2 does not belong to the track section part beyond the last checkpoint of the track section TS2 (said last checkpoint of TS2 may be checkpoint CP7, or a checkpoint further to the right in Figs. 1a, 1b; note that the latter situation resp. such a further checkpoint is, for simplicity, not illustrated in said figures), and therefore the updated track profile information will contain the correct actual speed limit corresponding to the correct actual turn setting of the switch 2. Therefore, the faked setting of the switch 2 in the former track profile information does not affect the safety of the further train voyage.

The above three cases are summarized in table 1 below.

table 1	checkpoint speed at CP6	setting of switch 2	speed limit at switch 2	remark
actual setting when train bypasses balise group 4a, as noted in database 8	zero	turn	40 km/h
setting assumed by tool 4b as track profile information for transmission at balise group 4a	zero	straight-forward	120 km/h
track profile information of the train after infill with target speed information for CP6 of 120 km/h (switch 2 changed into straightforward)	upgraded to 120 km/h	straight-forward	120 km/h	train passes CP6 with 120 km/h
track profile information of the train after infill with target speed information for CP6 of 40 km/h (switch 2 remains in the turn setting)	upgraded to 40 km/h	straight-forward	120 km/h	train passes CP6 with 40 km/h
track profile information with no infill	zero	straight-forward	120 km/h	train stops at CP6

It is worth mentioning that the target speed information transmitted to the train must correctly reflect the traffic situation with respect to the setting of the track element (here switch 2) subsequent to the last checkpoint (here CP6) in order to guarantee a safe train operation.
Therefore, for safety reasons, it may be necessary to disallow the infill in some situations. Typically, this is accomplished by defining particular track segments as "forbidden areas". When the train is in a forbidden area, the received target speed information is not used for replacing a checkpoint speed. Typically, the space between a balise group and a corresponding railway signal, wherein the railway signal is positioned at a track circuit boundary (insulation location) of the national ATP system, is defined as a forbidden area (see F1 in Fig. 1b), since the allocation of a target speed to a particular checkpoint may be unclear then. Further, often some distance behind a checkpoint is also defined as a forbidden area (see F2 in Fig. 1b). Note that there may be more reasons for defining "forbidden areas", though.
Note that the invention can also be used when, in the example of Fig. 1a and 1b, the railway signal 6 does not simply switch from "red" to "pass", but the switch 2 switches form "turn" to "straightforward" (note that this involves that the railway signal 6 switches form pass to stop and again to pass). Then the track profile information as transferred by balise group 4a assumes the "straightforward" (high speed) position of the switch even though the switch 2 is in "turn" (low speed) setting when the train passes balise group 4a. The on-board-unit may then upgrade the checkpoint speed from 40 km/h to 120 km/h in case the target speed changes from 40 km/h to 120 km/h. A safe passing speed of the train is secured by the correct target speed information for checkpoint CP6.
In summary, the invention relates to a method for operating a train (11) on a railway system (1), wherein the railway system (1) is equipped both with a train protection system with non-continuous information transfer, such as level 1 ETCS, and a target speed information system with a continuous information transfer, such as a national ATP system. The target speed information system is used to update the track profile information of the train protection system between information transfer points, such as balise groups (4a, 6a, 7a), by replacing checkpoint speeds of the track profile information with target speeds. However, the track profile information is not altered in other ways by the replacement; in particular there is no re-calculation of a track profile information by the on-board-unit (11a) of the train (11) for safety reasons. In order to be able to use the updated checkpoint speeds, the train (11) receives track profile information also for track section parts (13) adjacent and beyond the last forthcoming checkpoint with a corresponding red railway signal, and the setting of track elements, such as switches (2), in said track section part are assumed to allow the highest possible speed when transmitted to the train (11). A safe train speed is guaranteed by the proper choice of the target speeds. The target speed is provided by the existing target speed information system, without an intervention into it. The invention improves the train traffic flow on the railway system.

Claims

Method for operating a train (11) on a railway system (1),
- wherein a train protection system provides to the train (11) a track profile information about a forthcoming track section (TS1, TS2),
wherein the track profile information comprises a speed profile information for the entire forthcoming track section (TS1, TS2), location of checkpoints (CP4, CP5, CP6, CP7) within the forthcoming track section (TS1, TS2) and a checkpoint speed information for the last checkpoint (CP6) within the forthcoming track section (TS1, TS2),
wherein track profile information is provided non-continuously to an on-board-unit (11a) of the train (11) at discrete information transfer points of the railway system (1) upon bypassing of the train (11),
wherein the on-board-unit (11a) enforces a maximum train speed according to the track profile information,
- wherein a target speed information system provides to the train a target speed information, valid for the next checkpoint (CP4, CP5, CP6, CP7) of the forthcoming track,
wherein the target speed information is provided to the train (11) continuously,
- wherein in case the checkpoint speed according to the checkpoint speed information is "zero", the track profile information also covers a track section part (13) adjacent and beyond said last checkpoint (CP6),

- wherein in case said track section part (13) comprises a track element with different possible speed limits, wherein the speed limit depends on the current setting of the track element, the speed profile information provided to the on-board-unit (11a) belongs to the setting of the track element with the highest of the possible speed limits, independent of the actual setting of the track element,

- and wherein in case the target speed information for the said last checkpoint (CP6), for which a "zero" checkpoint speed is indicated according to the most recent track profile information of the on-board-unit (11a), indicates a "non-zero" target speed, then the on-board-unit (11a) allows the train (11) to approach and pass said last checkpoint (CP6) as if said the checkpoint speed according to the track profile information was indicating said "non-zero" speed, and obtains an update of the track profile information at a discrete information transfer point assigned to said last checkpoint (CP6).
Method according to claim 1, characterized in
- that the track profile information covers a track section part (13) adjacent and beyond said last checkpoint (CP6), independent of the checkpoint speed information,

- that in case the latter track section part (13) comprises a track element with different possible speed limits, wherein the speed limit depends on the current setting of the track element, the speed profile information provided to the on-board-unit (11a) belongs to the setting of the track element with the highest of the possible speed limits, independent of the actual setting of the track element,

- and that in case the target speed information for said last checkpoint (CP6) indicates a higher speed than the checkpoint speed information, then the on-board-unit (11a) allows the train (11) to approach and pass said last checkpoint (CP6) as if the checkpoint speed information according to the track profile information was indicating said higher speed, and obtains an update of the track profile information at a discrete information transfer point assigned to said checkpoint.
Method according to claim 1, characterized in that the track profile information always contains exactly one checkpoint (CP4, CP5, CP6, CP7).
Method according to claim 1, characterized in that the target speed information system may transmit the special value "no speed limit", and that the on-board-unit (11a) supervises a fixed speed limit in such a case
Method according to claim 1, characterized in that the location of the last checkpoint (CP6) corresponds to a position of a railway signal (6).
Method according to claim 1, characterized in that information transfer points are provided on the railway system (1) at least at all signals (4, 5, 6, 7).
Method according to claim 1, characterized in that the train protection system is a level 1 ETCS system.
Method according to claim 1, characterized in that the target speed limit information provided by the target speed information system originates from a local or national automatic train protection (=ATP) system.
Method according to claim 1, characterized in that that in case the on-board-unit (11a) wants to use a target speed for replacing a checkpoint speed, the train driver is requested to acknowledge said procedure before the on-board-unit (11a) allows the train (11) to approach and pass the checkpoint (CP6) using said target speed as the checkpoint speed.
Method according to claim 1, wherein the provided track profile information defines "forbidden areas" (F1, F2) of the forthcoming track section (TS1, TS2), with the on-board-unit (11a) not being allowed to accept target speed information for use in replacing a checkpoint speed when the train (11) is within a forbidden area (F1, F2).
Method according to claim 10, characterized in that a forbidden area (F1) extends adjacent and before a checkpoint (CP4, CP5, CP6, CP7).
Tool (4a, 6a, 7a), in particular software program, for reading out a track profile information of a forthcoming railway track section (TS1, TS2) of a train (11) from a database (8), and for delivering the read out track profile information to a discrete information transfer point of a train protection system,
wherein the track profile information comprises a speed profile information for the entire forthcoming track section (TS1, TS2) and a checkpoint speed information for a last checkpoint (CP6) within the forthcoming track section (TS1, TS2),
wherein in case the checkpoint speed according to the checkpoint speed information is "zero", the track profile information covers a track section part (13) adjacent and beyond said last checkpoint (CP6),
wherein the tool (4a, 6a, 7a) is designed such that in case said track section part (13) comprises a track element with different possible speed limits, wherein the speed limit depends on the current setting of the track element, the read out speed profile information delivered to the information transfer point belongs to the setting of the track element with the highest of the possible speed limits, independent of the actual setting of the track element.
Tool (4a, 6a, 7a) according to claim 12, characterized in that the read out and delivered track profile information also covers a track section part (13) adjacent and beyond said last checkpoint (CP6) when the checkpoint speed according to the checkpoint speed information is "non-zero".
Use of an on-board unit (11a) of a train (11) in a method according to claim 1, characterized in that the on-board-unit (11a) enforces a maximum train speed according to a stored track profile information about a forthcoming railway track section (TS1, TS2), wherein the track profile information comprises a speed profile information for the entire forthcoming track section (TS1, TS2), location of checkpoints (CP4, CP5, CP6, CP7) within the forthcoming track section (TS1, TS2) and a checkpoint speed information for the last checkpoint (CP6) within the forthcoming track section (TS1, TS2),
wherein the on-board-unit (11a) comprises means for receiving track profile information upon passing of discrete information transfer points,
wherein the on-board-unit (11a) comprises means for enforcing a maximum train speed according to the track profile information,
wherein the on-board-unit (11a) has an input for continuously inputting a target speed information of for the train (11), valid for a next checkpoint (CP4, CP5, CP6, CP7) of the forthcoming track (TS1, TS2),
wherein the on-board-unit (11a) is designed to allow the train (11) to approach and pass the last checkpoint (CP6) of the stored track profile information as if the checkpoint speed was indicating the speed according to the target speed information, which is higher than the checkpoint speed, provided that
- the on-board-unit (11a) has received a target speed information with respect to the last checkpoint (CP6),

- and the stored track profile information about the forthcoming railway track section (TS1, TS2) also covers a track section part (13) adjacent and beyond said checkpoint (CP6).
Use of an on-board unit (11a) of a train (11) in a method according to claim 3, characterized in that the on-board-unit (11a) enforces a maximum train speed according to a stored track profile information about a forthcoming railway track section (TS1, TS2), wherein the track profile information comprises a speed profile information for the entire forthcoming track section (TS1, TS2), location of a checkpoint (CP6) within the forthcoming track section (TS1, TS2) and a checkpoint speed information for the checkpoint (CP6) within the forthcoming track section (TS1, TS2),
wherein the on-board-unit (11a) comprises means for receiving track profile information upon passing of discrete information transfer points,
wherein the on-board-unit (11a) comprises means for enforcing a maximum train speed according to the track profile information,
wherein the on-board-unit (11a) has an input for continuously inputting a target speed information of for the train (11), valid for the checkpoint (CP6) of the forthcoming track (TS1, TS2),
wherein the on-board-unit (11a) is designed to allow the train (11) to approach and pass the checkpoint (CP6) of the stored track profile information as if the checkpoint speed was indicating the speed according to the target speed information, which is higher than the checkpoint speed, provided that
- the on-board-unit (11a) has received a target speed information,

- and the stored track profile information about the forthcoming railway track section (TS1, TS2) also covers a track section part (13) adjacent and beyond said checkpoint (CP6).