Create Links
Use the New Link dialog to create a link between a predecessor activity and a successor activity, and to assign the properties of a link.
Ways to access
Open a Link List from the Tilos Explorer and click Add Link on the right side.
Within the Activity Links tab, click 'Add Link'.
Options
General settings
Predecessor - Select an Activity that needs to occur before another Activity; this is the Activity where a link starts.
Notes:
To help you select the right predecessor and successor Activity for the link, this information is shown for the activities when you click in the list: Activity ID, name, predecessor, and successor (similar to what is shown for Gantt charts).
You can right-click in this list, select Incremental Search, and enter a specific text ‘string’ by typing the characters. Find the next matching string in the list (including in the following columns) by pressing the down arrow key.
Successor - Select an activity that needs to occur after another Activity; this is the Activity where a link ends.
Link Type - Select a required link type:
Start to Start - Make the successor activity start when the predecessor starts.
Start to Finish - Make the successor activity finish when the predecessor starts.
Finish to Start - Make the successor activity start when the predecessor finishes.
Finish to Finish - Make the successor activity finish when the predecessor finishes.
If you select this link type, you can check the Calculate end date of the successor box (below) to set the duration of a successor Activity so that its end date = the end date of its predecessor Activity. This setting will respect any lead or lag times associated with the link.
Calculate meeting point - This option can only be set for finish activities; it calculates the meeting point of two Activities working towards each other on the time and distance axis. Read the chapter Scheduling Activities - Calculate Meeting Point.
Note: Calculate meeting point can only be used if no advanced activity modeling (profile) is set. For a profile-based activity, it will be implemented later.
Lag - Enter a positive or negative time span (for a lead time) to keep a distance between the two activities.
Lag time unit - Define the lag time's units. Some lags appear in working time units; others appear in calendar time units, depending on the 'Calculate lag by' option.
Link category - Select a link category to control the link's line style and color.
Layer - Specify the layer on which to place the link. Links can be hidden or displayed using the settings in the Display tab. If you place links on different Layers, individual links can be hidden and shown.
Link-specific settings
Calculate lag by - Select an enhanced method to calculate the reschedule:
Calendar time - Enter the lag for the links in calendar time units only.
Working time of predecessor - Enter the lag for the links in working time units only.
Working time of successor - Enter the lead for the links in working time units only.
% work duration of predecessor - The field lag gets disabled and the percentage value for the lag gets entered in a separate date field.
Equipment mobilization - The field lag is disabled. The lag is calculated based on the fact that a certain moving time of the resource is needed to move from the end distance coordinates of one Activity to the start distance coordinates of the successor Activity. This move is done by applying a fixed speed or a distance profile. The lag represents the driving time from one place to the next. The following extra options can be set.
Fixed speed - If this option is set, the equipment speed for the whole distance is constant.
Speed profile - If a fixed speed is not set, then a distance profile can be selected. Additionally, a speed data field that contains the station-based speeds for the movement of the equipment can be selected.
Distance to successor - The field lag gets disabled. The lag is calculated based on the distance between the predecessor and the successor. Tilos makes sure that for the whole distance range, the two Activities do not overlap at all; the successor always follows the predecessor. The result of the cheap distance calculation is the lead lag in working time units and based on the link type set. This ensures that the CPM-based reschedule algorithm can calculate proper float values, like standard links would have been used. The following extra options can be set:
Distance lag - Define the gap in distance units between the two activities.
Predecessor is at - The field lag is disabled and gets calculated. The successor start time gets synchronized with the time that the predecessor is at the given location. These extra options can be set:
Predecessor has length - The field lag is disabled. The successor start time gets synchronized with the time that the predecessor has a user-defined performed length
Time lag - Add working time to the calculated lag from the distance option. This option does not work in combination with a seasonal profile.
Synchronize duration - Transfer the duration of the predecessor to the successor; the successor's duration is adjusted. The algorithm used for this calculation is:
When the calculation model for the Activity is set to Duration - Adjust the work rate so that the given work can be completed within a given duration.
When the calculation model for the Activity is set to Work rate - Copy the duration from the source Activity to the destination Activity.
Distance link: Ignore time settings - Define that the link only transmits the according distance coordinate to its successor Activity. The link sets on distance values, and no time calculation for the successor is performed. Usage: If a main process conditions the distance to be worked and some other Activities may follow or go ahead, working on the same distance and length, you can control that with a distance link to ahead or following Activities. Distance links are not producing loops in time schedule.
Update train setup on reschedule - Add to the resource assignments inside a chain of Activities (e. g., Activity 1 is the train ride into the construction side - Activity 2 is the work - Activity 3 is the drive out). If the resource setup on the main activity changes in the others also change. If this option is set, then the predecessor's resources having a role assigned gets copied to the successor. This is done only if the train setup of the successor is set to support the train. If no role is assigned to the resources, they are not copied.
Synchronize distance - Transfer the distance coordinates of the predecessor to the successor. Thus the successor is moved also in distance.
Note: Synchronize duration and Synchronize end date (see below) cannot both be checked at the same time.
Move the successor - Synchronize the distance coordinates of link source and destination, e. g., for a finish to start link, the end distance coordinate of the predecessor is set to start distance coordinate of the successor. The length of the successor is kept so the end distance coordinate changes as well.
Size the successor - Synchronize the distance coordinates of link source and destination, e. g., for a finish to start link the end distance coordinate of the predecessor is set to start distance coordinates of the successor. The distance coordinates are not changed so that lengths of the Activity get changed.
Start and end distance - Synchronize those distance coordinates. Start and end distance coordinates of predecessor and successor will be the same after a reschedule.
Size the successor (support train) - This option works similar to the size successor option, but makes some extra calculation to cover the train setup. This option gets automatically set if the dialogue: Create logistic Activities is used to create the links.
The distance calculation can also reflect offset. In track renewal with track renewal trains, a manhole has to be done. In this case, enter an offset of, e.g., 20 m.
If the shape is a parallelogram or a triangle, then lead and lag for the predecessor and successor can be selected and is reflected in the total offset calculation. It is added to the manual calculation.
Skip on import - Prevent the link from being actualized in case of an import.
Driving link
Calculate end date of successor - For a Finish to Finish link, set the duration of a successor Activity so that its end date = the end date of its predecessor's Activity, similar to using the Synchronize Duration function. Use this when you want a master Activity to control the parallel Activities in duration. The other Activities will finish at the same time as the master Activity. If you change the position of the green Activity, e.g., the size, the surrounding Activities are updated.
Note: This is only enabled if the duration can be set.
Example
With Calculate end date of successor enabled, when the duration and end date of the master predecessor Activity (green) is changed, the linked successor Activities (beige) change duration in response.
Note: If the start of the successor is >= the end of the predecessor, an error will be added to the error list when you reschedule.
Set quantity by predecessor - Set a successor Activity to automatically use the same material volume as its predecessor Activity. Use this to couple quantities for scenarios such as:
balancing mass haulage cut and fill quantities
setting a consistent volume for a surface where the first run is compaction, the second run is grading, and the third run is paving
Using this option, the quantity set for a predecessor is recalculated for all following Activities on the schedule.
Note: All material volumes (e.g., cut and fill quantities) are considered to be in compacted states; there is no accounting for bulkage, swell, or shrinkage.
Note: This link must be made prior to synchronizing duration, and the setting only applies if no progress has been made on the predecessor Activity.
Note: Synchronize end date and Synchronize duration cannot both be checked at the same time. To enable Set quantity by predecessor, the conditions are:
Link type = Finish to Finish
Calculation method on Activity = None, work rate, or length (not any duration)
Retain settings - Keep link settings from the previously used links. Then you can select whether or not you want to keep specific settings.
Next topic: ---
Further information
Calculate Intersection Points
Links From Distance Coordinates
Synchronize Activity Rates