@mcadv do you read what people are asking???
@David G. to your question:
Reservation not required for both trains (EC), please note that for the EC from Trieste to Ljubljana you have to pay a supplement for the Italian part (2,60€), you can buy it online via ÖBB tickets.oebb.at (one way ticket, and at 1x adult add as discount Interrail/Eurail Globalpass). You should be able to buy it also on board of the train.
On the same website (tickets.oebb.at you can buy a reservation for both trains if you want with the seat only option (3€/train).