Medium soft
As a Medium soft in the will control technology of the railway sector a crossover in a station called, in some cases, not part of a drive-in still from at least driveway and that's not the signal depending on subject. It is not completely cleared when entering and represents a special case to be considered when planning interlockings .
According to the DB Netz rules and regulations , a middle switch is "a switch in a station track that lies between the Zugspitze and the start signal when exiting or that can be occupied by the train".
Special feature of middle turnouts
As a rule, turnouts used by trains are part of an entry road (from a start signal of the free route to the destination signal in the station) or an exit route (from a start signal from the station to the free route). The signal dependency ensures that a start signal for a train journey can only be set to " run " when all the switches between the start and destination signals are locked in the required position for the respective route .
Mean turnouts represent a special case. These are turnouts that are in the area of the usual stopping place of a train or between the usual stopping place and the exit signal . They must therefore be included in the safeguarding of all routes that lead into and out of the relevant track. They are locked when an entry road is set up and remain locked as long as they are not broken up by the train when it comes to a stop in front of or on it in the station track. This would not be problematic if, after the train has entered, the exit road is set for the train to continue its journey. Middle switches remained closed as part of the entry road until the journey continued. No further precautions would be required.
A distinction is made between false and true middle switches:
- Intermediate turnouts that are located in the direction of travel in front of the regular route closing point are referred to as fake center turnouts. Their lock is released when the route is closed after the switch has been cleared. Such middle switches are cleared in the course of the entrance, the entrance road can completely dissolve (after clearing the route closing point) before / when the train stops at the regular stopping place.
- Real middle switches , on the other hand, are located in the direction of travel of the train after the end of the route in the destination track. In the case of a route signal box, the locking of a central switch is also released after the train has stopped on the target track (after the route train terminal has been cleared); As an occupied turnout, it is secured against switching in interlockings with automatic track vacancy detection, so the missing lock is per se uncritical. Due to the route resolution, however, there is no flank protection for the driven train. In particular, if there are no shunting routes at the station in question, inattentive staff could make a flank drive.
In the case of both real and fake middle turnouts , the speed displayed on the exit signal must also be viewed as a function of the middle turnouts.
In modern interlockings based on the track plan principle with gap-free, automatic track vacancy detection, however, middle switches remain closed after an entrance due to the non-resolving partial route, so that the side protection remains in place. If the train continues in the same direction, this remaining partial route of the entrance will be resolved with the clearing of the central switch in the course of the exit. When removing the train unit as a shunting drive, the partial route is also broken up. On the other hand, if you continue to travel in another direction, if this option was not taken into account when planning the interlocking, an auxiliary route resolution is required. Route signal boxes such as GS II DR track diagram signal boxes are more flexible in this regard and therefore less problematic.
Train formations from a previous shunting route , necessary complete dissolution of the entry route (e.g. for changing locomotives or train re-routing) or other operating cases in which a central switch is not closed by the entry route when the subsequent exit route is closed can also be problematic . The center points in front of the exit signal must be fully included in the signal dependency in all operating cases. In order to secure all necessary partial routes, central turnout partial routes are set up, which are set together with the exit route and extend to the exit signal. The MWT is sometimes preceded by a central turnout partial train route (as a shunting route), which is later upgraded to a partial train route (including flank protection).
Middle turnout partial routes are to be set up according to the DB rules, if the turnout is in a train station in the route before the start signal and additionally
- the turnout must be closed before the start signal shows a main signal travel concept (e.g. change of direction, wings, strengths / weaknesses, formation of trains / provision) or
- the route of the train leads from a normal stopping point over the switch and, in addition, the speed permitted for driving on the switch in the relevant line must be taken into account when signaling the travel aspect at the start signal.
Implementation in signal boxes
Simplified electronic interlockings (ESTW-R) cannot handle intermediate switches . In route signal boxes, central switches are locked both when setting routes into and out of the station track in question. There is a gap in interlockings without automatic track vacancy detection, since these intermediate switches can be switched when a route leading into the relevant track is disconnected, although they can and usually are occupied by vehicles.
Individual evidence
- ↑ Stephan Respondek: Terms . Directive 482.0009. December 11, 2016, p. 8 .
- ↑ a b c d Hans-Joachim Zoeller: Manual of ESTW functions . The security level in the electronic interlocking. 2nd Edition. Eurailpress , Hamburg 2005, ISBN 978-3-7771-0388-4 , pp. 35-38 .
- ↑ a b c d e Ulrich Maschek: Securing rail traffic . 4th edition. Springer Vieweg, Wiesbaden 2018, ISBN 978-3-658-22877-4 , p. 126-128, 192 f .
- ↑ Volker Surminski: List of Abbreviations . Directive 413.9701. Ed .: Deutsche Bahn. December 16, 2013, p. 3 .
- ^ Christian Wilhelmi: Middle turnout road (MWT) . October 1, 2012, p. 1 f .