This summer I will be in Krakow and I want to take the train to Lviv. I live in the Netherlands and informed here how to get tickets for the train. Here they told me I can buy tickets here which are tickets for a vice versa trip which I will have to use in a month given a certain starting date. They told me however that it is not possible to reserve a seat/bed on the train and that when I get there it is possible that the train will be full. Since I have one day to get there, I have to questions:
1) Can I reserve the places on the train in advance?
2) Are the trains normally full in the summer?