Sounds like a debugging exercise is needed:-
The first thing you need to establish is whether or not the train is actually activating the trigger you have set.
I do not know how much experience you have had with track triggers and session rules but you may want to check the Trainz Wiki page at https://online.ts2009.com/mediaWiki/...Track_Triggers
Next check that the Play Sound rule is correctly set and is working. I have never used the Play Sound rule but I would use the Message Popup Rule instead (which does allow sounds to be added). That way there will be a visual indication (even if the message just says "Activated") that both the rules have been activated.
Development: Trainz Plus - b119450
Testing: Trainz Plus beta - b119450
GTX1050Ti, RTX3060Ti and RTX3050Ti, Win 10 & 11