Euroloop

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The Euroloop subsystem is used to transmit the signal aspect to rail vehicles over the entire range of the distant signal distance . It thus expands the punctiform Eurobalise system in ETCS Level 1 . It is standardized at the European level by the ERA (Subset-044).

The central element is the leakage line called Euroloop at the foot of the rail. The data transmission takes place over the entire length of the loop, which can be up to 1000 m long and is terminated at the end . It is fed by the loop modem (LOOMO). The modem transmits in the frequency range from 9 MHz to 18 MHz and uses Direct Sequence Spread Spectrum for frequency spreading and for CDMA multiplexing . The data rate is 9567.4 bit / s. The telegrams sent come from a lineside electronic unit (LEU; trackside control unit) and their structure corresponds to the telegrams of the Eurobalises (see there). The telegram content is identical to that of the transparent data balise that is preceded by the loop.

A Eurobalise must also be arranged as an end-of-loop marker (EOLM) in the direction of travel in front of the loop, on the one hand as a position reference at the point (or instead of) the distant signal, and on the other hand for transmitting the CDMA code to the train. With this code the Loop Transmission Module (LTM) can receive the telegrams from the loop.

The LTM shares an antenna with the Balise Transmission Module (BTM). Its permanent 27 MHz field, which supplies and activates the Eurobalises with energy, is used in the Euroloop subsystem to activate the modem, which then modulates the telegrams continuously sent by the LEU and feeds it into the loop for 60 to 90 s.

history

ETCS was originally created as part of several research projects funded by the European Union , which were organizationally part of the A200 working group of UIC's own research institute ERRI. One of these research projects dealt with possible punctiform and (partially) continuous transmission systems. For the latter case, systems based on coded track circuits were originally planned, which were already widespread at the time (see article train control systems ). Due to the small amount of data that could be achieved, this proposal was rejected in favor of a conductor loop ( loop , routing type B3 according to specification ORE A46), as it was already used at the LZB . In this special loop patterns were (so-called. Instead of the usual today EOLM marker ) provided inside the loop. This proposal was also rejected.

For the solution with the leakage line, the same frequency range was originally specified as for the uplink of the Eurobalises (4.5 MHz) so that the same receiver could be used on the vehicle. However, it turned out that the reception of Eurobalise telegrams could be disturbed by the Euroloop. Due to the higher number of already installed balises, the Euroloop frequency range had to give way (with version 2.0.1 of the specification from September 2004) and Euroloops and LTMs built according to the old specification had to be adapted. In Switzerland, this affected around 400 track and around 2,700 vehicle equipment, which were adapted in mid-2010.

Due to a change in the TSI ZZS in May 2019, it was decreed that Euroloops should no longer be used on new lines to be equipped with ETCS.

use

The Euroloop is primarily used as a continuous form of transmission in sections in the context of ETCS Level 1. The transmitted data come from a decentralized LEU , usually coupled with a conventional signal . Technically, the Euroloop system can therefore be compared more with SELCAB than with the centrally controlled LZB.

The main reason for the introduction of the Euroloop was the exclusively punctiform action characteristics of a balise. This has a major operational disadvantage: if a vehicle receives, for example, a telegram with the information stop at 2000 m , this vehicle will stop somewhere a few meters beforehand, unless a slip path has been planned. Accordingly, with the Eurobalise alone it is not possible to issue another driving permit. This deficit can be remedied through the Euroloop. Relocated in front of the stopping area, it can be used to transmit a new travel permit before the next, practically inaccessible Eurobalise.

Instead of the Euroloop, ETCS also allows the use of radio-based transmission via GSM-R (so-called radio infill ) for this application . However, this requires additional, in the case of level 1, not necessarily available infrastructure.

If both Euroloop and radio infill are not used, classic main signals must still be provided. If the driver sees that such a pass allows him to pass, he may continue to drive at low speed (nationally different, e.g. 20 km / h) until the next Eurobalise. Only after this balise has been read out can the vehicle travel at full speed again. However, this approach reduces the average speed and thus the route capacity enormously.

In addition to being used for ETCS, Euroloop technology was also used in the past to implement automatic train operations.

literature

  • Michael Dieter Kunze: Subsystem on the infrastructure side . 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. 72-74 .

Web links

Individual evidence

  1. ↑ Uwe Dräger, Hansgeorg Kast: Functions and interfaces of Euroloop features of a European solution . In: signal + wire . tape 87 , no. 4 . Tetzlaff Verlag GmbH, 1995, ISSN  0037-4997 , p. 135-138 .
  2. ↑ European Train Control System ETCS - Status Report 2010. (PDF) Federal Office of Transport (BAV) , December 31, 2010, archived from the original on August 9, 2016 ; accessed on August 9, 2016 .
  3. ↑ Implementing Regulation (EU) 2019/776. (PDF) European Commission , May 16, 2019, accessed on February 1, 2020 .
  4. ↑ a b Burkhard Lege, Gerhard Hillenbrand: SST with EUROLOOP . In: signal + wire . tape 87 , no. 4 . Tetzlaff Verlag GmbH, 1995, ISSN  0037-4997 , p. 123-127 .