Half control distance
The half control distance describes a form of signaling at Deutsche Bahn in which two adjacent main signals are at half the braking distance.
introduction
Due to the long stopping distance of a train stop must pointing signals from the drivers by a precursor signal to be announced, which depending on the route in the main orbits m at a distance of 700-1300 m stands in front of the main signal. Since distant signals must be set up at least at the braking distance , a shortening of the distant signal often leads to a reduction of the maximum speed allowed.
A main signal regulates the entry into a train following section , in which as a rule at most one train may be at any one time. Since in Germany the distant signal always announces the next following main signal, the distant signal can at most be moved to the location of the preceding main signal and combined with it at one location. Since there can be no further main signal in between, the smallest possible distance between two main signals (which determines the length of a train path section) corresponds to the largest possible distant signal.
On heavily used routes there is sometimes a desire for a closer signal spacing in order to form shorter train sequence sections. The aim is to increase the capacity and performance of the infrastructure by allowing more trains to run in shorter succession. For this purpose, the half-control distance was developed, in which these requirements can be met via graduated signal patterns even with shorter to half the main signal distance. In the following sketches a length of 500 m is assumed.
functionality
In the core area of the half-control distance (in the figure in the area of signals 5 to 9), the full braking distance is ensured by announcing a main signal indicating a stop over two signal segments.
If signal 9 shows the signal aspect stop (Hp 0), the signal aspect expect stop (Vr 0) is shown on the distant signal of signal 5. In order to comply with the rule that a distant signal always announces the next main signal, signal 7 must be switched off operationally. To do this, the signal is switched to a beacon. The distant signal announces the following main signal. The distant signal has an additional white light that shows that it is a repeater of the distant signal.
Main signals showing travel are only announced via a signal section, since braking does not have to take place here, the shortened distance is not problematic.
The transition from the normal signal distance to the half-control distance (in the figure the area between signal 3 and signal 5) takes place via a special half-control announcement signal (called AN in the figure). The signal designation usually begins with an A. The signal is already in the half-control distance. This signal shows identification light when the following main signal shows stop. If two signal sections are free, i.e. the distant signal is expecting travel (Vr 1), it changes to the signal aspect travel. The signal cannot indicate stop because it cannot be announced in the normal braking distance. It also does not limit any track vacancy detection section.
use
The half-control distance was created by the Deutsche Bundesbahn in the 1950s, it is only used in its route network and in connection with the H / V signal system. Although the half-control distance was originally planned for the Ks signal system , the decision was made here to use the additional signals Zs 3v and Zs 3 to signal braking curves over several block sections with a small main signal distance. This downward signaling over several block sections was already used by the Deutsche Reichsbahn with HI signals . Your advantage is that the signal locations are much more flexible.
However, the half-control distance is only rarely used in the H / V signal system on particularly heavily used routes, for example in the area around Stuttgart Hbf station , on the main S-Bahn line in Cologne, in Düsseldorf, at Mainz-Kastel station in the Rhine -Main area and on the Munich S-Bahn line S1 in Oberschleißheim .
A further compression of the train sequence is possible with systems of the driver's cab signaling , in which conventional trackside signals can be partially or completely dispensed with and (almost) meter-accurate driving clearances and speed information can be transmitted to the driver's cab. This means that, in extreme cases, two trains can approach each other up to the length of their slip path (here usually 50 m). In Germany, liner train control is used in conjunction with CIR-ELKE system software. Such high-performance blocks are used, among other things, on the main line of the Munich S-Bahn and the line between Karlsruhe and Basel . A similarly dense block division is also possible with ETCS Level 2 .
literature
- Lothar Fendrich (Ed.): Railway Infrastructure Manual. Springer, Berlin / Heidelberg 2007. ISBN 978-3-540-29581-5 , p. 579.
- Jörn Pachl : System technology for rail transport - planning, controlling and securing rail operations. Vieweg + Teubner, 2008. ISBN 978-3-8351-0191-3 , pp. 53-55.
Individual evidence
- ↑ Jörn Pachl: System technology of rail traffic - plan, control and secure rail operations. Vieweg + Teubner, 2009. ISBN 978-3-8351-0191-3 , p. 54