So for german system i have some suggestions, because jpvdveer's phrases should fit well for Switzerland, but in Germany they are a little bit different.
In most regional trains the announcements play automatically and in the same way on each stations :
When the doors open it says on the outside of the train "RB/RE/S nach destination". Then if you departed it says "RB/RE/S nach destination. Nächste Station next stop."
Before the next stop it says "Nächste Station next stop. Ausstieg in Fahrtichtung rechts ( right ) / links ( left )." Before destination it says : "Nächste Station next stop. Dieser Zug endet hier. Ausstieg in Fahrtichtung rechts ( right ) / links ( left )."
So this kind of announcements on local trains should work very well with your automated announcement system if the correct phrases are implemented as they work the same way on each stop and are computer voices anyway. Maybe the side of exit could be solved with sliders, which the player can move for each stop because your system could not know, on which side the platform is. Or you cancel this detail information ...
The announcements on long distance trains are more individual as they are spoken by human and everybody does it a little bit different. But the information included is the same. They welcome the people like this after departure :
"Meine Damen und Herren, ich begrüße sie recht herzlich an Bord des ICE/IC/EC auf der Fahrt nach destination. Wir wünschen eine angenehme Reise. Unseren nächsten planmäßigen Halt next stop erreichen wir voraussichtlich um arrival time at next stop."
A few moments before arriving they say something like "Meine Damen und Herren, in Kürze erreichen wir next stop. Wir verabschieden uns von allen Fahrgästen, die hier aus- oder umsteigen und wünschen einen angenehmen Tag. Der Ausstieg hier in next stop befindet sich in Fahrtrichtung links / rechts."
This is a very simple construct, because there could be a lot more information like an advice to the onboard restaurant, information on delay or the connection trains on the next stop.
So they are a lot more complicated. Maybe you could implement standart announcements with the information given every time and a pool of additional announcements which are added randomly to these to not have every announcement the same. If you need some of this phrases, i could create some for you.
