Station block

The station block is part of the securing of train journeys of a railway in a station . In addition to electrical dependencies within the signal box (route definition), it also creates the dependencies between several signal boxes in a station. It can be found in all interlocking designs if there are routes in the station in which several interlockings are involved. In stations that are only secured by a signal box, the station block is limited to route definition and route resolution.

On the open road is Streckenblock applied.

description

The station block secures the train journeys within the station and ensures that

a train journey can only take place with the cooperation of the dispatcher , even if several interlockings - in Germany usually dispatcher interlocking and guard interlocking , in Austria and Switzerland usually command and control interlocking - are involved in setting up and securing a route,
the signal with which the train journey is to be permitted can only be set to travel with the consent of the bodies involved in setting, securing and checking the route,
the moving devices belonging to a route - switches and side protection measures - remain under lock and key even when the signal is reset to "stop".

functionality

The signaling dependencies between the command post and the guard interlocking are made with the station block functions

Issuing and receiving commands
Giving consent and receiving consent
Route definition and route resolution

manufactured.

Issuing / receiving commands

With the issuing of the command, the dispatcher instructs the switch attendant to check the route and to set the signal with which the train journey is to be permitted to move. The dispatcher can only issue orders if he himself has created the prerequisites in the part of the station that belongs to his area of testing and responsibility. This can be a route specification, but also just the closure of central switches of the station. The issuing of commands can also depend on the consent of other interlockings, the condition of the route block (e.g. in Austria) or the previously established route at the interlocking (e.g. in Hungary or earlier in the Netherlands).

Orders are received at the dependent signal box when the dispatcher issues orders. This gives the switch attendant the opportunity to set the signal to "run". With some types of construction (for example in Austria, Germany or Poland) it is only when the order is received that the switchman can finally secure the route, which is the prerequisite for being able to set the signal to "run".

approval

With the usual division in Germany (but also in Poland) into a dispatcher and guard interlocking, the switch attendant gives the dispatcher his consent to set up and secure a route. The switch attendant can only issue the approval if he has secured the part of the route that belongs to the control area of the guard interlocking with the route lever. In this way, he ensures that the required track systems in his test area are free of vehicles and that the switches are set. The completed blocking of the consent submission field also leads to the definition of the route lever that was previously operated.

The approval of the point keeper corresponds to the receipt of approval. This unlocks the route lever, which is locked in the basic position, in the dispatcher interlocking and thus gives the dispatcher the opportunity to secure the route and set the signal to "move" or, in the case of larger systems, to issue a command to another interlocking.

Route dependencies by means of approvals are also set up between dispatchers among each other at larger stations with station sections. In addition, they are set up at stations with intermediate switches or tracks that are difficult to see, for example at alternative stations in the mountains, and between signal boxes to secure routes.

From a technical point of view, the two processes “command” and “consent” are identical.

Route definition

The route definition also defines the folded route lever, with which the route is mechanically locked, in a block-electrical manner. The route definition is retained even if the signal with which the train journey was permitted is reset to "Stop".

The route resolution dissolves the block electrical route definition again. It is either activated automatically by the train after it has passed a train action point on the track, or it is operated by an employee - a dispatcher or switch attendant - who can check whether all the conditions for the route clearance are met.

If one signal box is responsible for the entire station, the consent and command functions are omitted. The station block then only consists of route definition and resolution.

Switzerland

In the SBB regulations , the expression “station block” can no longer be found in any valid regulations and is no longer taught in the training to become a dispatcher. This has to do with the fact that there are no longer any train stations in the SBB network in which guards and command stations still exist separately from one another. Even the inspection by the dispatcher to ensure that the tracks are free has now been carried out across the board by automatic track vacancy detection systems. The remaining functions “route definition” and “route resolution” are therefore not referred to separately as “station block”.

The so-called operating limit can be seen as a relic from those times. It divides the station along an imaginary line at the level of the reception building into two service areas, which in earlier times represented the two control areas of two signal boxes at the same station. This operating limit is still present today in the Domino type relay interlockings . It has the effect that a route from one side of the station to the other side can only be set in one step if the target signal is the one immediately after the operating limit. If there are several main signals or dwarf signals behind the operating limit, a route to the other end of the station can only be set in two steps: (1) from the start signal to the first signal behind the operating limit; (2) from the first signal beyond the operating limit to the target signal.

In the case of electronic interlockings (Simis C, Simis W, Elektra), however, this operating limit no longer applies.

literature

Anita Hausmann, Dirk H. Enders: Basics of rail operations . 2nd Edition. Bahn Fachverlag, Heidelberg / Mainz 2007.

Web links

Basics of signal box technology - station block. Retrieved January 4, 2015 .