Concatenation (ETCS)

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Eurobalise on slab track : A balise group can consist of one to eight such balises.
Balisenlesegerät ( beacon transmission modules , BTM) at a locomotive of the series 189 : therefore, the vehicle reads information from from the balise.

As concatenation (technical terminology also linking ) is the European Train Control System ETCS the logical link of a balise group designated by a subsequent balise group. The associated distance, along with other information, is transmitted from the route to the train via transparent data balise (in ETCS level 1 ) or radio (mostly in level 2 or 3 ).

As part of the linkage, the following balise groups in the direction of travel are announced and monitored with their identities and the distances to be traveled in between. This ensures the integrity of the route information transmitted. In the event of deviations, safety reactions can be triggered, for example emergency brakes . In particular, the chaining of individual balises also protects against driving in the wrong direction, which would otherwise require groups of balises consisting of at least two balises.

In addition, the interlinking serves to reset deviations in the distance measurement ( ETCS odometry ), which arise, for example, from slippage , before they become too large, and allows systematic deviations, e.g. due to decreasing wheel diameter, to be corrected .

Chained and non-chained balise groups

Balise groups each consisting of two balises in the Badischer Bahnhof in Basel. The direction of movement of the train can be clearly determined at each balise group.

As chained a balise group whose true concatenation information ( "linking information") is previously known. All balises of a linked group must be marked as chained with the value 1 of the binary variable Q_LINK in their telegram. Balise groups that contain repositioning information are also considered to be chained because these balise groups are pre-announced, marked as chained, and contain corresponding repositioning information. (A fixed absolute location of a balise, e.g. with route kilometer information programmed into the balise , is not possible because the route covered along a route is not clear, especially due to switches . The linking information can take into account the set route , for example .)

If a linked balise group is read by the vehicle, it becomes the decisive balise group (LRBG). In ETCS Levels 2 and 3, the train notifies the RBC u. a. the new LRBG with. From now on it serves as a spatial reference point, u. a. also for further position reports and driving permits .

Balise groups, each consisting of one balise, on block identifiers in front of a tunnel portal. The direction of movement of the train and the information provided by the balises for this direction can only be processed with interlinking information.

Unlinked balise groups must be identified as such ( Q_LINK = 0) and contain at least two balise groups. They may not be announced by chaining and they may not transmit any chaining information themselves (exception: infill ). They cannot therefore serve as a position reference and cannot become the LRBG.

Need not be chained beacons for example, that in ETCS Level 1 operation, a temporary speed restriction ( Temporary Speed Restriction secure, TSR). The permissible speed at a slow speed point can thus be monitored by the short-term installation of at least two groups of two balises without interfering with the long-term projected linkage. (With a link, only a group of two would be required.)

purpose

Balise groups each consisting of two balises on ETCS stop boards in front of a tunnel portal. In this way, the unauthorized passage of a train by emergency braking can be safely prevented, because it can determine its possibly wrong direction of movement even without any link information available.

According to the ETCS system requirements specification (SRS), the chaining serves three purposes:

  • To take action if expected balise groups are not found or are not found at the expected location.
  • To attach an oriented coordinate system to a single balise.
  • Correct the confidence interval of the odometry.

Chaining also provides additional protection against the dangers of unintentional reading of information from groups of balises that are away from the route being traveled ("cross-talk"). The margin of safety with which cross-talk from the neighboring track is excluded by limiting the field strengths and sensitivities is not great if a balise there is excited by another train.

By chaining it is also possible to "mask" certain balises for certain operating cases. So- called “Haltbalisen” are being laid on the ETCS routes of the VDE 8 project , the information of which is only taken into account by trains passing through a disturbed radio area. (If this balise is not found in the search window, an emergency brake is triggered. This ensures that a possible stop command from the balise is safely evaluated.)

In the "Staff Responsible" (SR) operating mode , no linking information (link lists) is managed.

A significant simplification of the ETCS operating mode Limited Supervision consists in dispensing with the chaining. This means that uniform data points can be used and measurement can be dispensed with.

Concatenation information

The chaining information for each of the chained balise groups is composed as follows:

  • the identity of the balise group
  • the nominal distance between the reference points of the balise group named "location reference" and the previous group in the list (or the LRBG for the first distance),
  • the laying accuracy (“accuracy”) of the balise group in relation to the danger point ahead. If a balise group contains two reference balises, this tolerance must cover both balises.
  • the direction in which the balise group is traveled. (Normal or opposite direction, "nominal" / "reverse")
  • the necessary reaction if the data of the expected balise group are not consistent: emergency braking ("train trip"), service braking or no reaction.

The driver must be informed of the reason for the braking. The braking may also only be released again when the vehicle is stationary. After the service braking has been completed, all location-related information in the on-board device must be deleted.

ETCS package 5 ("Packet 5") is used to transfer information on linking ("Linking Information") from the route to the train. This contains the following variables for the chaining:

  • Q_SCALE (scale to be used for distance dimensions , 2 bits, values: 10 cm, 1 m, 10 m)
  • D_LINK ( incremental distance to the next chained balise group, 15 bits, value range from 0 cm to 327,670 km); the distance ("linking distance") refers to the first balise of the two linked balise groups
  • Q_LINKORIENTATION (identifier for the orientation direction, 1 bit, 2 values: "0" if the train is traveling on the balise group in the opposite direction, "1" if the train is traveling on the balise group in the control direction)
  • Q_LINKREACTION (Linking reaction in the event of inconsistent data from the target balise group of the chaining, 2 bits, 3 values: Trip (TR) / emergency braking, service braking, no reaction)
  • Q_LOCACC (balise laying accuracy as limit deviation to be considered in both directions in meters, 6 bits, values ​​from 0 to 63 m)

Up to 29 further iterations of this group of variables can be transmitted as part of the package, the number of which is announced via the 5-bit wide variable N_ITER . A concatenated data packet can contain up to 30 concatenated balise groups. For example, a 30 km long driving permit can be issued if the mean distance in the chain of balise groups is only one kilometer.

Without concatenation information, the assumed balise installation error is determined by the national value Q_NVLOCACC . This is 12 m in the Deutsche Bahn network.

Processing on the vehicle

Single balise around 50 m in front of an ETCS stop board at which a double balise can bring trains to a stop even without active chaining. This enables trains with concatenation information to correct the confidence interval for their self-location. This makes it easier to get closer to the signal.

If the vehicle does not have any linking information, all balise groups may be taken into account. Otherwise it may only consider balise groups that

  • marked as chained and contained in the chaining information or
  • are marked as not chained.

Linked balise groups with the identifier "ID unknown" may only be taken into account if the On-Board Unit detects the chaining direction from the balise group itself, the balise group is driven over with the announced direction and the balise group contains repositioning information that is valid for this direction of travel.

The vehicle may only take into account chained balise groups contained in the chaining list,

  • from the earliest possible place at which the front safe Zugspitze ( max safe front end ) reaches the place of the balise group to
  • to the latest possible place at which the minimum safe front end has passed the location of the balise group,

which means that the confidence interval provided by the odometry for the position of the Zugspitze overlaps the search window (“expectation window”) for the position of the balise group. The former contains the position uncertainty of the previously linked balise group, the uncertainty of the position detection as well as the accumulated uncertainty of the path measurement and takes into account the distance between the Zugspitze and the balise antenna. The latter is defined by the nominal interlinking distances and the positional uncertainty of the balise group sought. The vehicle should expect one balise group after the other, according to the sequence of the linked list. It should jump to the next balise group in the list if the balise group was found within the search window or if a "linking consistency error" was found. If a linked balise group is found before the search window, the vehicle should check its linking consistency and jump to the next balise group in the linking list. As soon as the minimum safe Zugspitze has passed the search window of the last linked balise group, there is effectively no more chaining information.

The on-board device must be able to store at least 30 chained balise groups. A newly transmitted link information completely overwrites the stored link information unless the link information was transmitted as an infill, i.e. with a position reference to a group that has not yet been reached.

Planning and project planning

As part of the validation of ETCS track equipment, the correct mapping of the topology in the ETCS messages is checked. a. the chaining distances between the balise groups. In the ETCS topology, these can be mapped, for example, in a node - edge model, with the nodes corresponding to the linked balise groups and the edge lengths corresponding to the chaining distances.

Others

With the ETCS equipment in Luxembourg with ETCS Level 1 (Full Supervision), the chaining enables some of the data points to be laid with only one instead of two balises, since the necessary directional information can be derived from the chaining.

A manufacturer-independent interoperability test was carried out for the ETCS equipment in the Netherlands in 2003. a. different infill and repositioning groups between signals were tested using different chaining parameters.

The linkage is also used in the ETCS-like train control system S-Bahn Berlin (ZBS). The data point at the beginning of a signaling section announces the data points within the section. The linking reaction to data points that cannot be found or is faulty depends on the significance of the data point and ranges from a message to an emergency brake. The balise distances on which the linkage is based were checked as part of special “linking trips” by driving over them.

Web links

Individual evidence

  1. ^ A b Olaf Mense, Henri Feldt: Proposal for the introduction of ETCS Level 1 Limited Supervision at DB AG . In: signal + wire . tape 102 , no. 9 , September 2010, ISSN  0037-4997 , p. 6-13 .
  2. ↑ a b Also Germany with ETCS Level 2 . In: Eisenbahn-Revue International . No. 2 , 2016, ISSN  1421-2811 , p. 76-78 .
  3. ^ Ines Hamberger: ETCS operation of the Westbahn between Vienna and Salzburg . In: ZEVrail . tape 140 , no. 8 , August 2016, ISSN  1618-8330 , p. 292-297 .
  4. ↑ a b c Günther Koch, Jörg Schütte, Benedikt Wenzel: SAT.valid: Tool-based testing and validation of ETCS track equipment . In: signal + wire . tape 106 , no. 3 , 2014, ISSN  0037-4997 , p. 18-22 .
  5. ^ A b Klaus Hornemann, Bernd Fröhlich: Application of the Eurobalise at DB Netz AG . In: Signal + Draht Spezial . October 2015, ISSN  0037-4997 , p. 16, 17, 19 ( PDF file ).
  6. ↑ Christoph Lackhove, Benedikt Schreier: Project planning assumptions for ETCS cost estimation . In: ZEVrail . tape 134 , no. October 10 , 2010, ISSN  1618-8330 , p. 420-427 .
  7. ↑ ETCS specification , subset 023, version 3.3.0, section 4
  8. ↑ Norbert Apel, Jenny Strahl: Basic principles of Odometry . In: Peter Stanley (Ed.): ETCS for engineers . 1st edition. Eurailpress, Hamburg 2011, ISBN 978-3-7771-0416-4 , pp. 126-130 .
  9. ↑ a b c ETCS specification , subset 026, version 3.6.0, section 3.4.4.1
  10. ↑ a b c ETCS specification , subset 026, version 3.6.0, section 7.5
  11. ↑ ETCS specification , subset 026, version 3.6.0, section 8.4.2.1
  12. ↑ ETCS specification , subset 026, version 3.6.0, section 3.4.4.3
  13. ↑ ETCS specification , subset 040, version 3.4.0, section 4.2.4.8.1
  14. ↑ a b ETCS specification , subset 040, version 3.4.0, section 4.2.4.8.2
  15. ↑ ETCS specification , subset 026, version 3.6.0, section 3.6.4.3.1
  16. ↑ ETCS specification , subset 091, version 3.6.0, section 8.3.2.1
  17. ↑ ETCS specification , subset 026, version 3.6.0, section 3.6.4.1
  18. ↑ ETCS specification , subset 036, version 3.1.0, section 4.4.6.2.5
  19. ↑ ETCS specification , subset 036, version 3.1.0, section 4.2.5.1
  20. ↑ a b c Jürgen Haas: Fallback level for line equipment ETCS Level 2 without signals . In: signal + wire . tape 107 , no. 10 , 2015, ISSN  0037-4997 , p. 6-10 .
  21. ↑ Stefan Berger: Trainguard MiniLEU S11 - experiences with the lineside electronic unit . In: signal + wire . tape 106 , no. 9 , 2014, ISSN  0037-4997 , p. 22-24 .
  22. ↑ Reiner Behnsch, Jörg Peter Osburg, Detlef Schwarz: Mixed ETCS equipment concept for the Basel node . In: signal + wire . tape 103 , no. December 12 , 2011, ISSN  0037-4997 , p. 12-18 .
  23. ↑ ETCS specification , subset 026, version 3.6.0, section 3.4.4.2
  24. ↑ ETCS specification , subset 026, version 3.6.0, section 3.6.4.2 b, 3.6.4.2.1 and Fig. 13a.
  25. ↑ a b ETCS specification , subset 026, version 3.6.0, section 3.16.2.6
  26. ↑ ETCS specification , subset 026, version 3.6.0, section 3.14.1.6
  27. ↑ a b c ETCS specification , subset 026, version 3.6.0, section 7.4.2.2
  28. ↑ ETCS specification , subset 026, version 3.6.0, section 7.4.1.1
  29. ↑ ETCS specification , subset 040, version 3.4.0, section 3.3.1.5
  30. ↑ a b c d ETCS specification , subset 040, version 3.4.0, section 4.3.2.1.1, i)
  31. ^ Richard Kahl: ETCS Level 2 . In: Jochen Trinckauf , Ulrich Maschek, Richard Kahl, Claudia Krahl (eds.): ETCS in Germany . 1st edition. Eurailpress, Hamburg 2020, ISBN 978-3-96245-219-3 , pp. 204 .
  32. ↑ ETCS specification , subset 026, version 3.6.0, section 3.4.4.4.1
  33. ↑ ETCS specification , subset 026, version 3.6.0, section 3.4.4.4.2
  34. ↑ a b c d e ETCS specification , subset 026, version 3.6.0, section 3.4.4.4.3
  35. ↑ ETCS specification , subset 026, version 3.6.0, section 3.4.4.4.5
  36. ↑ a b ETCS specification , subset 026, version 3.6.0, section 3.4.4.4.6
  37. ↑ ETCS specification , subset 026, version 3.6.0, section 3.4.4.2.1.1
  38. ↑ ETCS specification , subset 026, version 3.6.0, section 3.4.3.2.2
  39. ^ Henri Werdel, Jean-Jacques Kolb, André Feltz, Hans Kast: Equipping the entire Luxembourg railway network with ETCS Level 1 . In: signal + wire . tape 95 , no. 9 , 2003, ISSN  0037-4997 , p. 19-24 .
  40. ^ Nick Cory: Current ETCS projects in the Netherlands . In: signal + wire . tape 96 , no. 6 , 2004, ISSN  0037-4997 , p. 17-25 .
  41. ↑ Britta Bandke: A new train control system for the S-Bahn Berlin (ZBS) . In: signal + wire . tape 93 , no. 10 , 2001, ISSN  0037-4997 , p. 30-34 .
  42. ↑ Dirk Peukert: ZBS route equipment - new train control system for the Berlin S-Bahn . In: ZEVrail . tape 139 , no. 4 , April 2015, ISSN  1618-8330 , p. 116-125 .