@amberfirefly a problem in Europe is that train connections tend to be poor, especially between countries and also expensive. Much more expensive than flying :( :(
Having tried it, I found that essentially traveling by train is only possible for rich travelers.
I believe that train connections is one of the few things that the Soviet Union did get right and I hope the EU will have affordable train trips in the future. It would increase cohesion of the union too I think.