Hi,
I have a short question about train etiquette - specifically about the trains with reserved seats, or generally anything “above” the typical local commuter train.
Are you supposed to greet the passengers that are sitting next to the seat you’re taking? In Poland, when entering the compartment and taking the seat I’d usually say some kind of “good morning” to the fellow passengers, even if afterwards I’d go to sleep or put on headphones etc 
Same when leaving. But I wonder if it’s also the same in Japan, or are you supposed to strictly mind your own business and don’t bother people? I really love the idea of the whole train being basically the “silent zone”, but then I started wondering about details