Language is so interesting! "In the train" isn't a thing. We would say "on the train" but honestly "in the train" would make more sense. We aren't actually on it haha.
And if I were to try to use "in the train" I'm trying to think what that would even mean. Maybe in the engine, or some structural part of it? Like you're trapped? Lol
Im not leaving a comment on this particular question but it seems like theres some confusion on the word "En" because you can be ON a train or AT the airport but we us "En," and for the English speaker thats comprehended as IN. So IN a hotel makes sense. But being IN a bus or IN an airport seems a little harder to wrap our heads around.
for native English speakers it's a simple case of horses for courses and translating "En" to the equivalent English equivalent which colloquially is the "correct" word to use in those circumstances. so, we can be in the hotel and , although we physically are in the bus or in the train, we would use the words on the train. also on a boat or ship, but in a car, or a balloon or a lift , but on an escalator. then again we would be at the theater or the cinema or the racetrack or the football stadium, but in the disco or the ballroom...etc etc