In many cases, the running direction of a vehicle carrying out a vehicle journey does not have to be regarded separately. This is the case if all vehicle journeys are carried out in the 'ahead' mode (one-way vehicle, especially all buses and some trams) or if the running direction is irrelevant (railcar operation in rapid transit). Anyhow, in some cases it is requested, that the running direction of the vehicle combination is always the same, for example, because the station wagon of a train is expected to stop at a fixed position at the platform or because the vehicle dynamics of push-pull trains depends on the running direction.
Thus it is optionally possible to take the running direction into account for line block checks and manual line blocking Visum. For this purpose, for each turn in the network it has to be specified if this turn means a change of the running direction. Useful data can be provided by turn standards (Nodes and turns) based of turn types.
Thus, each movement in the network inherits information on running direction changes. Along a line route which means in the course of a vehicle journey a running direction change occurs especially where a turn with the property Is change of running direction is traversed. If a line block takes the running direction into account (attribute Regard running direction), these changes of the running direction will be visualized in the line block display.
Image 189: Display of a change of the running direction in the course of vehicle journey block items. The line route makes a U-turn in the station "TFS"
Accordingly, the empty trip block items obtain information from the network whether running direction changes occur in their course. If the empty trip is based on a system route, the running direction changes are located in the same manner as for vehicle journeys and will similarly be visualized in the line block display. If there is no system route, then the route search determines whether an even or an odd number of direction changes appears; only this is relevant to line blocking. Thus, empty trip block items with an odd number of running direction changes are centre-subdivided in the view.
For user-defined block items the information whether running direction changes are included is explicitly stored with the attribute Is change of running direction . Hence, also a rotary journey (U-turn or triangle-shaped) can explicitly be modeled as user-defined block item.
If the running direction has to be regarded for a line block, the line block check will verify the item end - item start changeovers in the sequence of line block items and define the running direction at the beginning of the activity for each block item. A direction fault is recorded if a vehicle journey section is run in either direction by this line block on different calendar days. For a closed line block, a direction fault is additionally recorded if the running direction changes after the closed line block has been completed.
The line blocking procedure cannot directly evaluate the change of running direction information. Thus it cannot intentionally generate line blocks without direction faults. In the line blocking procedure, the parameter Regard running direction works as follows:
- Regard running direction: Subsequently to the line blocking procedure, the line blocks are checked for direction faults. If applicable, the appropriate fault status is set.
- Do not regard running direction: For the line blocks, the attribute Regard running direction is set to 'false'.
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Attribute |
Description |
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Is change of running direction |
If attribute default values from the turn standard are allocated to a turn, the original turn attribute values will be replaced by the allocated default values for the selected attributes. This makes the default value allocation easier. To all turns of the U-turn type, for example, the property Is change of running direction can be allocated. |
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Attribute |
Description |
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Is change of running direction |
The value of this attribute indicates, whether traversing this turn means a change of the running direction. This applies to line routes and system routes as well as to the change of direction determination for empty trips during the line block check. Furthermore, this attribute is evaluated for the item end - item start changeovers in the sequence of line block items within a line block. |
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Attribute |
Description |
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Is change of running direction |
This is true if the line route item is located at a node, where the line route course uses a turn with the property Is change of running direction. |
