How to Use Track Triggers

What are Triggers?

Triggers are invisible markers (invisible in Driver Mode but visible in Surveyor Mode) that are placed on a track. They can be programmed to "trigger an event" when a train (any train or a specific train) passes over them in Driver Mode.

The "event" is a message that is transmitted by the trigger to certain Session Rules that have been programmed to "listen" for the message. When one of those listening rules detects the message, it can be forced into action by executing preset instructions.

(left) A Track Trigger in place on a track visible in Surveyor Mode. The "5.00m" is the trigger detection radius

Adding a Trigger

The Track Trigger is placed on the track using:-

• the Tracks tool, and
• the Trackmark Mode button.

Select the Trigger Object from the list of installed objects Click the Add Object button Click the track position where the trigger is to be placed.

Configuring a Trigger

As soon as a new trigger has been placed, its properties window will open on the screen. It will be given a default name and assigned to the currently active layer.

To change the assigned layer click on the layer box and select a new layer. To change the trigger name click on the default name and enter a new name. To confirm the changes click on the Tick icon on the bottom right of the window.

Triggers have a "detection radius" that controls how close a train has to approach to trigger the event. The smaller the radius the closer the train. This radius is set in the Advanced Properties section of the Tools window.

Click the Advanced Tab to open its properties. Enter a new radius value in metres. Click the Set Trigger Radius button Click on the trigger that has been placed on the track.

Creating a Trigger Event

Trigger events are handled by the Trigger Check Rule which is added to a session in the Session Editor.

• The Trainz Wiki Link Trigger Check Rule contains detailed information on this rule.

Open the Session Editor from the Surveyor Main Menu. Select the option Edit Session from the drop down menu list.

	Click the Add button then scroll down to select the Trigger Check rule Click the Tick icon.

This will add the Trigger Check rule to the session.

With the Trigger Check rule highlighted, click the Edit button. This will open its properties window.

For this example we will leave all settings unchanged and simply identify the trigger to be used.

	Click the Add trigger link and select the trigger you have previously added.

• Click the Tick icon on the selection list
• Click the Tick icon Trigger Check properties window.
  
  

To test your trigger event you will need to add a rule to the Trigger Check. When you are back in the Session Editor window, click the Add button to add a new rule.

	Scroll down the rule selection window to select the Message Popup rule Click the Tick icon.
	The Message Popup rule should now appear directly below the Trigger Check rule. The new rule will show a red cross because it has not yet been configured.

The Message Popup Rule has to be indented so that it becomes a Child of the Trigger Check Rule.

	With the Message Popup Rule highlighted, click the Indent (right arrow) button.

The Message Popup Rule is now controlled by the Trigger Check Rule but it still has to be configured to show a message.

• With the Message Popup Rule highlighted, click the Edit button.

Set the properties as shown:- CheckON Close previous message popup windows Select Option Button Custom text Enter a short text message (you are limited to about 6 lines of text) To add an icon to the message:- Click the link click here to set and either scroll down the list to find a suitable icon (some will not be suitable), or simply type "icon stop" in the text box Click the Tick icon.

The finished Message Popup.

Again, click the Tick icon to exit the Message Popup Rule then exit the Session Editor.

Add a consist to your layout a short distance from the trigger (but further away than its radius), save the surveyor session, and then test in Driver Mode.

Another example of using the Trigger Check Rule can be found in the Message Popup Rule Applications link below.

Related Trainz Wiki Links:

• Controlling Junctions in Sessions
• Message Popup Rule Applications
• Message Popup Rule Examples
• Navigation Point Applications
• Navigation Point Rules Examples
• Parent and Child Rules
• Using Variables in Sessions - Examples