Ghocaughie72
It depends, the answer to your question is answered in detail e.g. => here (scroll down to “Reservations…”)
Your app screenshot already refers to the train operator’s website, who of course would like to sell as many reservations as possible. For this particular tourist train, you would book a seat
=> here
I can’t help with any recent experience, how full the train would be on a weekday like tomorrow with a not-too-stellar weather forecast.
