Julie Brooks-Girskiene I have never taken an international train though, do you have all of the same complications as flying?
In a word… No (or at least not in Europe).
If you take Eurostar between England and France then you 'check-in' and go through passport control before boarding but you don't have to check in bags and it's much quicker and easier. Or at least it used to be, I haven't taken it since Brexit.
Other train journeys within the EEA you just buy a ticket and get on. Depending on the journey you either cross borders without even noticing, or passport control and customs officers will get on at the last stop in the country you are leaving, pass through the train while it is travelling and do their checks, and then get off at the next stop in the second country.