EP3061666B1

EP3061666B1 - Signalling system for a railway network and method for the full supervision of a train realised by such a signalling system

Info

Publication number: EP3061666B1
Application number: EP15305284.0A
Authority: EP
Inventors: Stéphane Besure; François Hausman; Bertrand Badot
Original assignee: Alstom Transport Technologies SAS
Current assignee: Alstom Transport Technologies SAS
Priority date: 2015-02-24
Filing date: 2015-02-24
Publication date: 2020-07-22
Anticipated expiration: 2035-02-24
Also published as: EP3061666A1; AU2016201090A1; AU2016201090B2

Description

The present invention relates to a signalling system for a railway network, more particularly a signalling system based on the ERTMS/ETCS standards.
The application field of the present invention relates to the control of trains such as high-speed trains, regional trains, commuter trains, and the like.
The European Rail Traffic Management System, ERTMS, and the European Train Control System, ETCS, are international standards for Automatic Train Control, ATC, aiming at the interoperability of trains from one country to the other and the increase of the traffic with an optimal safety level.
For example, the article Maarten BARTHOLOMEUS and Martin ZWEERS: "A recipe for a fast nationwide migration to robust ERTMS L3", SIGNAL+DRAHT, TELZLAFF VERLAG GMBH, DARMSTADT, DE, Vol. 105, n° 9, 1 September 2013 (2013-09-01), pages 13-18, is a general article relative to a pure ERTMS Level 3 signalling system, able to create and manage L3 routes.
In ETCS, ATC is of the based on communication type, known by the acronym CBTC for "Communication Based Train Control ". CBTC relies on the presence of a computer on-board each train, called EVC for "European Vital Computer". An EVC determines a number of operating parameters and communicates with various ground systems to allow the train to realize the mission assigned to it.
Subset 026 of the ETCS standard defines several different levels of train control and supervision. In particular, it defines ETCS Level 2.
An example of signalling system compliant with ETCS Level 2 will now be presented in relation with figure 1.
In terms of structure, the signalling system comprises, on-board each train, an EVC, and, on the ground, a Radio Block Centre, RBC, an interlocking system, IXL, and a supervision system, ICC for "Integrated Control Centre", located in a control centre, and various trackside equipment connected to object controllers, located along the railway tracks.
An EVC is connected to at least one communication unit on-board the train, which is adapted to establish a radio link with a base station of a communication infrastructure. For example, the radio link is of the GSM-R type.
The communication infrastructure is itself connected to a communication network.
The systems in the control centre and the object controllers are also connected to the communication network.
The railway network is divided into fixed sections, each section corresponding to a portion of a railway track. For example, in figure 1, A6-A3 is a two end section (one entry point and one exit point), A3-A5-A2 is a three end section (two entry points and one exit point), etc. The border between two successive sections is identified in figure 1 by a vertical line.
This division of the railway network is physical: signal lights or panels are erected near the border of each section to inform the driver.
In addition, each section is equipped with specific trackside equipment, such as axle counters or track circuit.
The IXL determines an occupancy state of each section indicative of the presence of a train on the corresponding section from the detection data generated by the trackside equipment. For example, section A6-A3 is equipped with axle counters at each of its end points, so as to count the number of axles entering and exiting of the section. If this total number is null, the occupancy state of the section is "not occupied" and if it is not null, the occupancy state is "occupied".
In terms of data flows, the signalling system ensures the safe movement of a train on a railway network in several steps. An operator first requests, through the ICC, the creation of a route for a given train to move for example from a departure station to an arrival station.
From the section currently occupied by the train, the IXL checks whether or not, the next section among the sections making up the itinerary is in the occupancy state "not occupied". If this is the case, this section is reserved for that train and IXL considers the next section of the itinerary. The loop stops when all the sections of the itinerary have been considered or when a section is in the occupancy state "occupied".
Then, for all the reserved sections, the IXL commands, if necessary, the trackside equipment to put a reserved section in the correct operative state: for example for a section which is a switch, the operative state is "left" or "right".
A route is created once all the reserved sections are in the correct operative state.
The route which has been created is then passed to the RBC, which computes a Movement Authority, MA, for that train, based on a map of the railway network memorised by the RBC.
This MA contains different pieces of information, such as the speed limit at each point of the route. The MA in particular comprises a stop point up to the train is authorised to move. This stop point coincides with the end point of the last reserved section of the route.
The MA is then transmitted to the EVC of that train. On reception of the MA, the EVC calculates speed curves and brake profiles in order to control the train movement in Full Supervision (FS) mode along the route. In particular, the braking curves take into account the fact that the train must not go beyond the stop point of the MA. Consequently the speed of the train must be null at this stop point.
If the train goes beyond the stop point, an automatic train protection function activates an emergency braking.
These different steps are repeated each time a new route is created for the train in order to upgrade the MA in accordance with the train progression.
In such an ETCS Level 2 signalling system, the route created for a train ends at the end of the section whose neighbouring section (in the direction of the movement of the train) is "occupied" as determined by the IXL. The MA being determined from the route, the train cannot enter the neighbouring section on which a leading train is circulating. Thus, the separation between two successive trains is guaranteed by the IXL, which manages the occupancy sate of the sections and creates routes with the constraint "only one train on a given section at a time".
Beside the full supervision mode, the ETCS level 2 defines an on-sight mode, OS mode, to enter on occupied sections in case of anomalies or joining operations. In this mode, the driver has to drive the train on-sight at a reduced speed and EVC controls that the train remains inside the occupied section.
Subset 026 of the ETCS also defines ETCS Level 3.
The main difference between ETCS Level 2 and ETCS Level 3 is relative to the EVC.
An EVC compliant with ETCS Level 2 periodically sends position reports to the RBC. A position report comprises an estimated position of the train, calculated by suitable sensors on-board the train. But this position information is not used to determine the occupancy state of the section on which the train is currently circulating: this is done by the IXL. This position is used to display the position of the train on a view of the railway network in the control centre and internally by the RBC for specific ETCS functions.
An EVC compliant with ETCS Level 3 periodically sends extended position reports to the RBC, which comprises not only an estimated position of the train, but also a piece of information relative to the integrity of the train. If the train is integral, i.e. all the coaches of the train are still connected together, the RBC is able to calculate both the position of the front of the train and the position of the rear of the train.
The idea in ETCS Level 3 is that the RBC computes the MA of a following train based on the position of the rear of the leading train. The MA is computed in order to authorise the following train to move up to the rear of the previous train (taking into account a safety margin): each meter of the railway track released by the leading train can potentially be allocated to the MA of the following train.
In a signalling system based on ETCS Level 3, the train detection function is thus based on the train position reports. The number of conventional train detection devices, like track circuits or axle counters, can be reduced but it imposes the constraint to upgrade the complete train fleet to ETCS Level 3 first.
Document MAARTEN BARTHOLOMEUS AND MARTIN ZNEERS: "A recipe for a fast nationwide migration to robust ERTMS L3", SIGNAL + DRAHT, TELZLAFF VERLAG GMBH, DARMSTADT, DE, vol. 105, no. 9, 1 September 2013 (2013-09-01), pages 43-48, XP001583680, ISSN: 0037-4997, discloses an ERTMS Level 3 supervision system which, when a leading train loses its integrity, switches to Level 2.
However, there is a need for increasing the traffic on existing railway networks equipped with a signalling system of the ETCS Level 2 type. For example in figure 1, section A2-B1 is a bottleneck for the traffic.
One manner to increase the traffic is to reduce the headway between trains, i.e. the separation distance between two successive trains.
There is thus a need for a new way of managing the separation between trains.
To this end, the invention provides a signalling system according to claim 1 and a method for the full supervision of a train according to claim 10.
The invention allows upgrading the railway network to an ETCS Level 2/Level 3 mixed level, which is not possible if the solution is based only on Level 3 train position report. This will allow train not equipped with a train integrity system to circulate on the railway network without degrading existing performances. This will allow increasing the traffic without additional trackside equipment.
The invention and its advantages will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

Figure 1 is a general schematic view of the structure of an ETCS Level 2 signalling system;
Figure 2 is a schematic view of the data flow in the signalling system according to the invention;
Figures 3 and 4 are schematic representation of the process of train separation realised by the RBC of the signalling system of figure 1 and 2; and,
Figures 5 to 7 are schematic representation of the process of route creation realised by the IXL of the signalling system of figure 1 and 2.

The deployment of a signalling system 10 on a railway track 12 is shown schematically in figure 1.
The railway track 12 is divided into sections, such as two end sections A6-A3, A2-B1, etc., or three end sections A3-A5-A2, B1-B6-B4, etc.
The control centre 14 centralises a supervision system, ICC, an interlocking system, IXL, and a Radio Block Centre, RBC.
Along the tracks, object controllers 16, managed by the IXL, are capable of actuating trackside equipment such as switch blades for switches or barriers for level crossings.
These object controllers 16 are also capable of acquiring information from track circuits or axle counters.
The communication system has two main components: the wired communication network 20 linking the object controllers 16 to the control centre 14 and the GSM-R telecommunications network 22 providing communication between the RBC in the control centre 14 and EVC on-board a train, such as train 1 in figure 1.
Along the tracks, beacons 30 of the Eurobalise type are set in known positions. In conjunction with odometer sensors on-board the trains, these beacons are used by an EVC to determine the position of the train.
The current position of the train is periodically sent to the RBC, in position reports, for example over a GSM-R network..
Along the tracks, there are also fixed panels as A3 or B1 associated with key points, typically in the vicinity of the end point of a section.
The ground architecture of the signalling system 10 is compliant with a signalling system ETCS Level 2.
According to the invention, signalling system 10 is augmented with an additional sectioning, called DSS sectioning.
Broadly, over the ETCS level 2 division in fixed sections of the railway network is superimposed a Dynamic Sub-Sectioning, DSS, of the sections for ETCS Level 3. This dynamic sub-sectioning is managed by the RBC.
For example, segment A2-B1 of 20 km is sub-divided in five sub-sections of 4 km each. This sub-sectioning is virtual, because it is not associated with any particular trackside equipment or modifications of the view displayed in the control centre or on a console in the cab.
The DSS sectioning allows the circulation of trains equipped with an EVC compliant with ETCS Level 3 in its capability to report the position and the integrity of the train this EVC equips. Such trains will now be called L3 trains. Trains whose EVC is compliant with ETCS Level 2 (no integrity information in the position reports) will be called L2 trains.
With DSS sectioning, several trains can occupy the same section and the creation of routes can no longer be made by the IXL alone, based on the occupancy state of the sections and the constraint "only one train on a section at a time" like performed in ETCS Level 2. The existing routes defined for ETCS Level 2 are kept but these routes, called L2 routes, are completed with new routes foreseen for the movement of L3 trains in FS mode into an occupied section, called L3 routes. The conventional L2 routes are created by IXL based on fixed section information while the new L3 routes are created using RBC information related to the DSS sectioning.
These principles, schematised in figures 2 by the addition of a DSS interface 30 between the RBC and the IXL, will now be explained in more details.
The method for the full supervision of a L3 train realised by the signalling system 10 comprises:

the creation of a L3 route by the IXL, said route comprising a segment which is in an occupancy state "occupied" based on the information delivered by trackside equipment and on which is currently circulating a leading L3 train;
the upgrade by the RBC of a MA for a following train based on the last position report received from the leading L3 train and sending the upgraded MA to the following train.

By reference to figure 3 and 4, a process 100 will be described by which the RBC calculates MAs for the following train 1 based from the position reports sent by the leading train 2. We consider here that the RBC has received a L3 route that includes a segment, namely segment A2-B1, on which train 2, which is a L3 train, is currently moving.
At step 110, the RBC receives a position report from train 2.
At step 120, if, in said position report, the piece of information indicative of the integrity of the leading train indicates that train 2 is integral, then the RBC determines the position of the rear of train 2, from the estimated position of train 2 mentioned in the position report received and a piece of information relative to the safe length of train 2, while taking into account a safety margin.
At step 130, RBC calculates a possible new end of MA location d(end of MA) for train 1. As shown in figure 4, this possible new end of MA location d(end of MA) corresponds to the distance between the start of the segment and the rear of train 2 (safety margin included), rounded to a multiple of an elementary distance d0. d0 corresponds to the size of the sub-sectioning of the considered segment, either predefined or dynamically defined. This means that the possible new end of MA corresponds to the last dynamic sub-section that is free (compared to train 2 safe rear position d(safe train rear)), i.e.: $d (end of MA) = integer (d (safe train rear) / d 0) * d 0 .$
At step 140, the RBC compares the current MA end location with the possible new one.
At step 150, the RBC upgrades the MA of train 1 by moving the stop point of the MA to the possible new MA end location.
Finally, at step 160, the RBC transmits the upgraded MA to the EVC of train 1.
The elementary distance d0 of the DSS can be defined for each section individually. This distance can be predefined or computed dynamically in function of the track characteristics and train dynamics. When configurable like in the example, it corresponds to the subdivision of a given section by a simple section parameter of the integer type. The section parameter defines the number of sub-sections to be considered for a given segment. For example, a segment of 10 km can be decomposed into 10 sub-sections of 1 km or 20 sub-sections of 500 m. A sub-section does not correspond to an object in the RBC but is a predefined distance which can be used directly in the train separation function on the given segment.
With a position report every 5 s for example, the train position is updated every 150 m for trains traveling at 30 m/s. This is coherent with a sub-division of sections in sub-sections of 500 m. This DSS sectioning allows to give extended MAs to the following train much faster (around every 15 s in the example) than with the L2 sectioning (only when the 10 km section is freed, so, after more than 5 min).
By reference to figure 5, 6 and 7, the manner an L3 route is created will be presented.
First of all, for a sub-divided section, like section A2-B1, the RBC maintains an attribute, called Route Release RR. It has the value "0" while the rear of the leading train 2 has not passed the entry point A2 of that section. It has the value "1" once the rear of the leading train 2 has passed the entry point A2 of that section.
The process 200 of creation of an L3 route for the following train 1 comprises the following steps.
Train 1 is on an initial segment, A6-A3, corresponding for example at a departure station.
In step 210, an itinerary is allocated to train 1 in order it reaches a final segment, B6-B3, corresponding for example at an arrival station.
Then, in step 220, the operator requests, through the ICC, the creation of an L3 route for train 1, which is an L3 train according to a database of train description.
The request is send to the IXL, which, based on the L3 type of route to be created performs the following actions.
In step 230, from segment A6-A3 on which train 1 is currently circulating, the IXL checks whether the occupancy state of the next segment along the itinerary is "not occupied" or "occupied".
If the next segment is "not occupied", at step 240, the IXL reserves said segment for train 1 and adds said segment into the L3 route, and then considers the next segment of the itinerary;
If the next segment is "occupied", the IXL requires information from the RBC, namely the value of the RR attributes for that segment. Thus, at step 250, the IXL checks the current value of the RR attributes for the segment. For example, as shown in figure 6, at IXL level, segment A2-B1 is "occupied" and at RBC level, the position reports confirm at least one train on segment A2-B1.
At step 260, if the RR value of the next segment is "1", the IXL reserves said segment for train 1 and incorporates said segment into the L3 route, and then exit of the process of L3 route creation. RR equals to "1" means that the rear of train 2 has passed the entry point A2 of segment A2-B1 and that train 2 is reporting its integrity. Thus train 1 could be authorised to enter section A2-B1.
If the RR value of the next segment is "0", the IXL ends the process of L3 route creation. RR equals to "0" means that the rear of train 2 has not yet passed the entry point A2 of segment A2-B1 or that train 2 has not reported its integrity. Thus train 1 could not be authorised to enter section A2-B1.
Then the IXL command the operative states of the segments composing the created L3 route and finally sends the created L3 route to the RBC.
Then the RBC calculates the MA of train 1.
The train 1 then moves along the tracks according to its current MA. The RR attribute is set to 0 with the crossing of signal A3. As represented in figure 6, train 1 enters section A2-B1, but can not go beyond the stop point which corresponds to the end point of the second sub-section (i.e. beyond an intermediary point at two times d0 from the entry point A2 of that section).
The L3 route can be released as soon as the rear of the following L3 train has completely crossed the entry point of the "occupied" segment. The RBC updates the RR attributes with value "1" (provided that train 2 still reports of its integrity) and the upgraded RR attribute is available for the IXL.
Once the L3 route is released, a new L3 route creation request for another train can be accepted by the IXL and could lead to the creation of an L3 route comprising the occupied segment.
If the attribute RR is not available due to a degraded mode (radio loss, for example), a new L3 route creation request is rejected as long as the segment is occupied and has a RR attribute equal to "0".
The RBC uses the information of the L3 route it receives to allow train 1 to enter on the segment A2- B1 and uses the subdivision of that section to extend the MA of train 1 based on position reports of train 2 based of process 100.
In figure 6, it can be seen that, whereas an L3 route ends at the exit point of a section (as a L2 route, as can be seen in figure 7), the corresponding MAs can have a different stop, in particular for sub-divided sections when they are in an "occupied" state.
On the contrary, as can be seen in figure 7, the stop point of MAs corresponding to an L2 route always coincide with the end point of a "not occupied" section.
To be more precise, and in connection with the ETCS Level 2 standard, for example in the current version 3.3.0 of subset 026, the L3 route allows a train to enter on an "occupied" segment and to move in full supervision mode, following the leading L3 train that frees track sub-sections as it progresses along the section, this being materialized by its position reports. In comparison, the entry of a train into an occupied section is only possible in OS mode in ETCS Level 2.
In ETCS Level 3, for the supervision from the control centre, the operator keeps a view similar to the one he had in ETCS Level 2 in terms of the occupation of the railway tracks. The concept of signal to signal itinerary is preserved and primary detection based on track circuits and the axle counters gives the occupancy state of the segments of the line, which are managed more finely by the RBC with the sub-sectioning. Trains are localised by their position reports, as in ETCS Level 2, except that more than one train can be localised in the same segment. Consequently, the level of regulation and traffic supervision rely on conventional ETCS Level 2 systems. The essential difference is the possibility for the operator to request the creation of an L3 route on a given itinerary.
In ETCS Level 3, this view is also the one the driver has. The driver can see the signals corresponding to the entry and exit point of each section. Between these points, the in cab console displays the distance with the rear of the leading train. For the driver, there is not any notion of sub-sections.
Any abnormalities in the position reports lead to the invalidation of the DSS sectioning.
For example, taking into account that the position report emitted by a train comprises an attribute relative to the type of its EVC, the RBC checks the compliance of the EVC type with ETCS Level 3. If the EVC type of a train is not compliant, the RR attributes keeps the value "0", meaning that the IXL will not be able to create an L3 route for the following train.
More generally, a segment is invalidated by the RBC in the following cases:

Detection of the breaking of the train, the position report indicating the train is no more integral;
Radio failure (after expiry of a timer associated with the corresponding train);
Failure of the integrity confirmation device on board the train (after the expiry of the timer associated with the corresponding train);
Train Logout (end of mission).

Once the IXL receives an invalidation of a segment from the RBC or from the operator through the ICC, the IXL shall inform the RBC that it switches to an unconditional OS mode on the segment so as to remove the MA of the trains on the segment.
The release of the segment is then determined by the track circuit or the axle counter corresponding to that segment. More generally, an invalidated segment can also be released by the movement of a sweeping ETCS Level 3 train in OS mode through the complete segment. This principle can be used at least to reset automatically an axle counter section after a failure or to clear an invalidated segment in ETCS Level 3 when there is no conventional detection in fall-back.
As it will be apparent for the man skilled in the art, the present signalling system allows an increase of the traffic on a given railway by reducing the separation distance between successive trains. With DSS sectioning, the train separation function is maintained by the IXL at the segment level and by the RBC within a sub-divided segment.
In addition this is not realised with additional equipment (in particular, trackside equipment or additional signals along the tracks), so that the cost of the deployment of this solution has a reduced cost.
In addition, the movement of a sweeping ETCS Level 3 train in OS mode permits to manage degraded modes like the failure of an axle counter section or an invalidated segment in ETCS Level 3.
Finally, this solution is inscribed in the process of upgrading ETCS systems from Level 2 to Level 3.

Claims

Signalling system (10) for a railway network (12) comprising:
- a ground architecture comprising a control centre (14) centralizing a supervision system, ICC, an interlocking system, IXL, and a Radio Block Centre, RBC; and,

- on-board each train (1, 2) circulating on the railway network, a European Vital Computer, EVC, each EVC being configured to send position reports to the RBC and receive Movement Authority, MA, from the RBC,
the ground architecture of the signalling system being compliant with the European Train Control System level 2, the signalling system having fixed sections, the IXL being capable of creating routes, called L2 routes, based on the occupancy state of the sections and the constraint "only one train on a section at a time",
characterised in that the signalling system is augmented with a Dynamic Sub-Sectioning - DSS, managed by the RBC, wherein a DSS interface (30) is provided between RBC and IXL, in which:
- the IXL is configured to create a route, called L3 route, for a following train (1), said L3 route comprising a section (A2-B1) which is currently occupied by a leading train (2), said leading train being equipped with an EVC configured to provide, in the position reports sent, a data relative to the integrity of the leading train, and

- the RBC is configured to upgrade the MA of the following train (1) based on the last position report received form the leading train (2) and to send the upgraded MA to the following train, wherein the RBC is configured to manage a separation distance between the leading train and the following train on said section, by calculating a distance between the rear of the leading train (2) and a stop point of the current MA of the following train, and, when said distance is greater than an elementary distance (d0), said elementary distance corresponding to a size of the subsectioning of the considered section as defined by the DSS, by extending the current MA to a distance corresponding to a multiple of said elementary distance such that a possible new end of the MA corresponds to the last dynamic sub-section that is free.
Signalling system according to claim 1, characterised in that said elementary distance (d0) is predefined, the division of a section in a plurality of sub-sections being accessible in a description database.
Signalling system according to claim 1, characterised in that said elementary distance (d0) is dynamically computed in function of a track characteristic and/or a train dynamics.
Signalling system according to any one of the preceding claims, characterised in that it complies with European Train Control System level 2 and has a full supervision mode, FS mode, and an on-sight mode, OS mode.
Signalling system according to any one of the preceding claims, characterised in that an EVC having the capability to report on the integrity of the train it equipped is an EVC complying with European Train Control System Level 3.
Signalling system according to any one of the preceding claims, characterised in that an EVC not having the capability to report on the integrity of the train it equipped is an EVC complying with European Train Control System Level 2.
Signalling system according to any one of the preceding claims, characterised in that it offers the possibility to request the creation of said L3 route based on DSS sectioning.
Signalling system according to any one of the preceding claims, characterised in that the system maintains an attribute (RR) for each sub-divided section, allowing to create said L3 route for a following train (1) comprising said section (A2-B1) when said section is currently occupied by a leading train (2).
Signalling system according to claim 8, characterised in that the attribute (RR) has a specific value when the system detects that the rear of the leading train has passed the entry point of said section and that said leading train is reporting of its integrity.
Method for the full supervision of a train realised by a signalling system, characterised in that, the signalling system being a signalling system (10) according to any one of the preceding claims, the signalling system (10) comprising:
- a ground architecture comprising a control centre (14) centralizing a supervision system, ICC, an interlocking system, IXL, and a Radio Block Centre, RBC; and,

- on-board each train (1, 2) circulating on the railway network, a European Vital Computer, EVC, each EVC being configured to send position reports to the RBC and receive Movement Authority, MA, from the RBC,
the ground architecture of the signalling system being compliant with the European Train Control System level 2, the signalling system having fixed sections, the IXL being capable of creating routes, called L2 routes, based on the occupancy state of the sections and the constraint "only one train on a section at a time",
the signalling system being augmented with a Dynamic Sub-Sectioning - DSS, managed by the RBC, wherein a DSS interface (30) is provided between the RBC and IXL, the method comprises, in a full supervision mode:
- the creation of a route for a following train (1), called L3 route, by the IXL, said L3 route comprising a segment (A2-B1) which is in an occupancy state "occupied" based on the information delivered by trackside equipment and on which is currently circulating a leading train (2) of the type configured to send position reports comprising an estimated current position of the leading train and a piece of information indicative of the integrity of the leading train;

- the upgrade, by the RBC, of the Movement Authority, MA, for the following train (1) based on the last position report received from the leading train (2), by managing a separation distance between the leading train and the following train on said section, by calculating a distance between the rear of the leading train (2) and a stop point of the current MA of the following train, and, when said distance is greater than an elementary distance (d0), said elementary distance corresponding to the size of the subsectioning of the considered section as defined by the DSS of the signalling device, by extending the current MA to a distance corresponding to a multiple of said elementary distance, such that a possible new end of the MA corresponds to the last dynamic sub-section that is free; and

- the sending of the upgraded MA to the following train.
Method according to claim 10, characterised in that it comprises a step of determining the position of the rear of the leading train, from the estimated position of the leading train mentioned in the position report received and a piece of information relative to the length of the leading train, while taking into account a safety margin.
Method according to claim 10 or claim 11, characterised in that the creation of a route comprises:
- from the segment on which the following train is currently circulating, checking whether the occupancy state of the next segment is "not occupied" or "occupied";

- if the next segment is "not occupied", reserving said segment for the following train and incorporated said segment into the route;

- if the next segment is "occupied", checking if the value of an attribute of said section allows the following train entering the occupied section and incorporated said segment into the route.
Method according to claim 12, characterised in that the system maintains the attribute by verifying that the rear end of the leading train has passed the entry point of said section and if the leading trains is reporting its position and integrity, the value of said attribute allows the following train entering the occupied section when both of these conditions are verified.
Method according to any one of claims 10 to 13, characterised in that the signalling system stops the DSS sectioning of an invalidated section in case of the detection of an anomaly in the set comprising:
- the EVC of a train is not of the European Train Control System Level 3 type;

- the communication between the system and the train EVC is lost;

- the EVC of a train indicates a loss of integrity.
Method according to claim 14, characterised in that the signalling system is configured to clear an invalidated section with the movement of a sweeping European Train Control System Level 3 train in on-sight mode, OS mode, through the whole of the invalidated section.