Parameters of the line blocking procedure
All parameters required for line blocking without vehicle interchange are also taken into account for line blocking with vehicle interchange. For line blocking with vehicle interchange, additional settings are required (Line blocking: Configuration tab).
Element |
Description |
Block version |
In the drop-down list, you can select one of the line block versions of the network for line blocking calculation. The attributes Number and Code of the selected line block version are displayed (Attributes of line block versions). |
Line blocking time period |
The attribute Line blocking time period is displayed for the block version selected (Attributes of line block versions). Note If the line blocking time period differs from the analysis period, a warning will be displayed concerning potential subsequent PuT operational indicator calculations. |
Line blocking with vehicle interchange |
If the option has not been selected, line blocking is calculated without a vehicle interchange. Notes This option is only available if the Detailed line blocking add-on is activated. If the option is selected, three more tabs are displayed that are only relevant for line blocking with vehicle interchange (Line blocking: Configuration tab). |
Note: Other properties of the selected block version are displayed in the tabs. |
Line blocking: Basis tab
Element |
Description |
Consider only active vehicle journey sections |
If this option has been selected, only active vehicle journey sections are considered for line blocking. Note Additionally, you can reduce the amount of considered vehicle journey sections to the unbound vehicle journey sections only. |
Consider only unbound vehicle journey sections |
If this option has been selected, only unbound vehicle journey sections are considered for line blocking. Note Additionally, you can reduce the amount of considered vehicle journey sections to the active vehicle journey sections only. |
Take forced chainings into account |
If this option has not been selected, any existing forced chaining is ignored during line blocking. Vehicle journey sections which are linked by forced chainings are not considered and planned together but as separate activities. If this option has been selected, any existing forced chaining is ignored during line blocking. Vehicle journey sections linked by forced chainings are treated and planned as a single activity (Fundamentals: Forced chainings). |
Line blocking: Properties of line blocks tab
Note: Some of these settings are only provided if the Detailed line blocking add-on is activated (Enabling or disabling add-ons). |
Element |
Description |
Build closed blocks |
If this option has been, closed blocks are calculated (Fundamentals: Open and closed blocks). Note This option is only provided if no annual calendar has been selected. |
Start and end only permitted in depots |
If this option has been selected, blocks start at a depot and end at a depot. Start depot and end depot do not need to be identical. Note This option is only provided if the option Build closed blocks has not been selected. |
To the block start, add element of type |
If this option is selected, you can choose a user-defined block item type from the drop-down list (Creating a block item type). As the first block item, an item of the select type is added to each open PuT line block. Note The option is only provided if the Build closed blocks option has not been selected and if at least one user-defined block item type has been defined. |
To the block end, add element of type |
If this option is selected, you can choose a user-defined block item type from the drop-down list (Creating a block item type). As the last block item, an item of the select type is added to each open PuT line block. Note The option is only provided if the Build closed blocks option has not been selected and if at least one user-defined block item type has been defined. |
Regard running direction |
If this option is selected, the orientation of the line blocks with the property Regard running direction will be checked at the end of the line blocking procedure:
If one of these criteria is not satisfied, the status direction fault will be assigned to the line block. For line blocks generated by the line blocking procedure, the attribute Regard running direction is set = true. |
Secondary chaining criterion |
Via the options, you can influence the structure of transfers between vehicle journey sections in the line block (Fundamentals: Decomposition of the flow into blocks). Differentiated duration of layovers The distribution of the layover times is as irregular as possible, in other words, there are more short and long layovers than average layover times. The aim of this is to obtain long layovers which can be used as maintenance time slots. Even duration of layovers The distribution of the layover times is as even as possible. Such blocks are exceptionally resistant to disturbances. Line purity It is attempted to only run vehicle journeys of the same line in a block or to at least avoid line changes within a block as often as possible. No specific requirements In this dimension, no requirements are set concerning the result. Even line blocks Select this option if you want Visum to calculate line blocks that are as similar as possible for each calendar day of the block time period. This makes it easier to perform line blocking in real operation. In addition, line block readability is improved. Note This option is only available if your line blocking time interval is longer than a day. |
Duration of blocks (intended number of block days) |
If closed blocks are generated, you can use the options to influence the duration of the blocks (Fundamentals: Decomposition of the flow into blocks). Note These options are not available if Even line blocks is selected in the Secondary chaining criterion section. Preferably build long blocks Blocks have as many block days as possible. This means that the single vehicles traverse multiple line paths. In the most extreme case, all vehicle journeys of a partition are covered by a single line block. Preferably build short blocks Line blocks have as few blocking days as possible. No specific requirements In this dimension, no requirements are set concerning the result. |
Required user-defined block item types |
Minimum duration of user-defined activities The user-defined activities defined in the block version have at least the specified duration. |
Line blocking: Interlining tab
Note: In this tab, various settings of the block version are displayed (Attributes of line block versions). |
Line blocking: Layover times
In the top section of the tab, various settings of the block version are displayed (Attributes of line block versions).
In the Interpretation of pre and post preparation times section, you can make settings for the preparation time. This allows you to save vehicle costs or change the timetable.
Element |
Description |
Use pre/post-preparation time as specified |
If this option is selected, the layover time is used as specified for the block version (Attributes of line block versions). |
Soft interpretation of pre/post-preparation time |
Select this option to make settings for the interpretation of the layover time. Note This option is only available if you select Consider pre/post-preparation times on the Layover times tab (Attributes of line block versions). |
Allow negative layover time (i.e. timetable changes) |
Select this option to make settings for the interpretation of negative layover time. Note The entry of a negative layover time might lead to time faults during the block check (Fundamentals: Line block check). You can avoid this problem by adapting the timetable or creating additional vehicle combinations. |
Minimum fixed layover time/Minimum negative layover time |
Only one of these options is available. The fixed part of minimum the layover time in minutes that must not be fallen short of. Note This option is only available if, on the Layover times tab, under the attributes of the block version, the options Consider pre/post-preparation times (Attributes of line block versions) and Soft interpretation of pre/post-preparation time are selected. The share of the negative layover time that leads to a timetable change is indicated in minutes. The value is automatically given a minus sign. |
Variable portion of minimum layover time |
Value indicates the variable part of the minimum layover time, by which the layover time can be reduced if costs can be saved. Together, the fixed and variable parts form the minimum layover time. |
Save one vehicle combination if the time falls below the minimum layover time by less than |
Indicates the reduction in layover time with which one vehicle combination is no longer required. Example: The value 10 means it is more cost-efficient to accept a layover time fallen short of less than 10 minutes than to deploy an additional vehicle combination. A shortfall of exactly 10 minutes means the costs for the shortfall and the costs for an additional vehicle combination are the same. A shortfall of more than 10 minutes is only cost-efficient if more than one vehicle combination is no longer needed. Note A shortfall of layover time is penalized. The penalty costs can only be offset by vehicle cost savings. This is why there is only a shortfall of layover time if the penalty costs can be offset by vehicle saving costs. |
Line blocking: Transport systems tab
Element |
Description |
Same operator for next vehicle journey |
If this option has been selected, the succeeding trip can only be a vehicle journey which is run by the same operator. |
Same TSys for next vehicle journey |
If this option has been selected, the succeeding trip can only be a vehicle journey using the same transport system. |
Same line for next vehicle journey |
If this option has been selected, the succeeding trip can only be a vehicle journey of the same line. |
List |
The list contains all vehicle combinations of all possible combinations of the items operator, transport system, and line, depending on the options selected above. Empty trip-TSys Use the drop-down list to select the empty trip transport system for the respective combination. Note In the section Transfer empty trip transport system of the marked row, you can transfer the setting of one row to other rows. |
Transfer empty trip transport system of the marked row |
You can copy a transport system selected in the list to other vehicle combinations. Select the rows to which you want to transfer the empty trip transport system of the selected row:
|
Filter displayed combinations |
Use the selection list to switch on a filter with which you can filter the column Empty trip-TSys according to different criteria.
This option resets a previously set filter and all combinations are displayed.
This option only displays combinations for which there is at least one vehicle journey section in the current state of the network that has this combination of properties.
The filter only shows combinations where the default empty trip transport system is not selected. |
Line blocking:Costs tab
Element |
Description |
Costs of an activity |
In this list, you can enter the weight by cost component which shall be regarded during the cost calculation. |
Coefficient |
Weighting factor by cost component |
Attribute |
List of line block attributes, whose attribute value is regarded if the coefficient for the attribute is greater than 0. |
Cost rate |
Attribute values; each of them is multiplied with the particular coefficient and the line block attribute value. |
Value if no VehComb |
This user-defined value by cost component is used for vehicles for which no vehicle combination has been defined. |
Line blocking: Configuration tab
On this tab, you can specify a reference solution to be used and set further configuration parameters. Some options are only available for line blocking with vehicle interchange.
Element |
Description |
Maximum number of iterations |
Line blocking terminates after the entered number of iterations. |
Number of iterations without improvement |
As convergence criterion, enter the number of iterations, after which the solution must be improved to iterate further. |
Number of solutions per iteration |
The higher the number of solutions which are determined per iteration, the higher the quality of the result to be expected. Note Both the time required for the calculation and the required memory capacity will increase in this case, however. |
Random seed |
In the case of otherwise unchanged settings, you determine a different result with a new starting value. With the same starting value and unchanged settings you can reproduce an existing result. |
Use reference solution |
If the option has not been selected, a reference solution is used for the line blocking. If the option has been selected, you can select and use a block version of the network in the list as reference solution. The attributes Number and Code of the selected line block version are displayed (Attributes of line block versions). Notes
|
Output extreme solutions found (Pareto-Optima) |
If this option is selected, the extreme solutions (Pareto-Optima) found in the course of optimization are saved. These extreme solutions would be optimal with a different weighting of the objective function components. An additional block version is created for each extreme solution. The evaluations of the extreme solutions are output as notes. Regardless of this, the final solution that is optimal according to the current weighting is written to the selected target block version and the evaluations of the extreme solutions are output as notes. |
Line blocking: Objective function tab
On this tab, you determine the weight of each single component of the objective function (Fundamentals: Solution evaluation via objective function). Some components are only available for line blocking with vehicle interchange.
Element |
Description |
Component |
In each row, this column contains a cost component of the objective function.
Note The criterion is available only if mandatory user-defined line block item types are required in the block version.
|
Factor |
In this column, you can enter a factor for each component after double-clicking the respective row. This way, you specify the weight with which the component enters the objective function. |
Weight (%) |
This column outputs the automatically determined share of the total weight 100% for each user-defined factor. |
Line blocking: Settings for objective function components tab
On this tab, you can specify the use of attributes.
Element |
Description |
Section Number of vehicle units |
Attribute for number of vehicle units Use the button to select the vehicle units attribute which determines the number of vehicle units. |
Section State of charge |
Minimum state of charge In the input field, enter the value for the minimum state of charge that is used in the calculation of the objective function. |
Volume and capacity section |
Attribute for volume of vehicle journeys items Use the button to select the vehicle journey items attribute which determines the volume. For dimensioning of the vehicle combination use Select the desired option in case the volume of a vehicle journey section is higher than the capacity of the scheduled vehicle. This option refers to the objective function component Consideration of volumes. Average volume If this option has been selected, the average capacity overload over all vehicle journey items of the section will be evaluated. Peak volume If this option has been selected, the peak capacity overload over all vehicle journey items of the section will be evaluated. You specify how the vehicle capacity is included in the calculation. You can also specify not to account for the vol/cap ratio. Use total capacity Select this option for consistent use of the total capacity as capacity. Use the seat capacity Select this option for consistent use of the total seating capacity as capacity. Capacity switchover due to the attribute value Select this option to choose an attribute of vehicle journey items whose value indicates the criterion used to determine the capacity.
Attribute for destination vol/cap ratio factor Use the button to select the vehicle journeys attribute which determines the desired vol/cap ratio. |
Operating times section |
Desired operating times between... In the input fields, enter a lower and an upper value in hours for the total duration of the operations. Output of the operating time windows in attribute An operation can be composed of various activities outside the depot. Select an attribute in which to store a consecutive integer that is identical for activities in an operation. This combines the activities. Note The section is displayed only if mandatory user-defined line block item types are required in the block version. |