In my opinion the main "low hanging fruit" Europe has with trains are international birders, especially if they're trying to compete with flying.
Trains in Poland work great, trains in Germany work pretty well but every train I've taken between Poland and Germany has been delayed. The standard thing is that while you're in Poland they claim the delay is because of previous delays in Germany and while you're in Germany they blame delays from Poland.
If you're trying to do something more advanced like get across Germany to Belgium or France & eventually the UK the it gets quite annoying.
Trains in Poland work great, trains in Germany work pretty well but every train I've taken between Poland and Germany has been delayed. The standard thing is that while you're in Poland they claim the delay is because of previous delays in Germany and while you're in Germany they blame delays from Poland.
If you're trying to do something more advanced like get across Germany to Belgium or France & eventually the UK the it gets quite annoying.