At the start of a train trip, people search for a good seat, and some of them take a careful look at the people nearby who have already chosen their seats to see if they will make good neighbors.
It might help if we each wore a little sign saying in what ways we will and will not be likely to disturb other passengers, such as: Will not talk on cell phone; will not eat smelly food.
Included in mine would be: that I will not be talking on my cell phone at all, aside from perhaps a short communication to my husband at the beginning of the trip home, summarizing my visit in the city, or, more rarely, a quick warning to a friend on the way down that I will be late; but that I will be reclining my seat back as far as it will go, for most of the trip, except when I am eating my lunch or snack; that in fact I may be adjusting it slightly, back and up, from time to time throughout the trip; that I will sooner or later be eating something, usually a sandwich, sometimes a salad or a container of rice pudding, actually two containers, though small ones; that I am as tidy as I can be with the salad, but it is awkward and difficult; that I am tidy with the rice pudding, taking small bites, though when the sealed top of the container is removed it can make a loud ripping noise for just a moment; that the sandwich, almost always swiss cheese, with in fact very little cheese, mostly lettuce and tomato, will not be noticeably smelly; that I may be somewhat more restless than some other passengers, and may clean my hands several times during the trip with a small bottle of hand sanitizer, sometimes using hand lotion afterwards, which involves reaching into my purse, taking out a small toiletries bag, unzipping it, and, when finished, zipping it up again and returning it to my purse; but that I may also sit perfectly quietly for a few minutes or longer staring out the window; that I may do nothing but read a book through most of the trip, except for one walk down the aisle to the restroom and back to my seat; but that, on another day, I may put the book down every few minutes, take a small notebook out of my purse, remove the rubberband from around it, put that rubberband around my wrist, and make a note in the notebook; that I may keep unscrewing the top of my water bottle and taking a drink of water, especially while eating my sandwich and right afterwards; lastly, that after a day in the city I may untie my shoelaces and slip my shoes off for part of the trip, especially if the shoes are not very comfortable, then resting my bare feet on top of my shoes rather than directly on the floor, or, very rarely, that I may remove my shoes and put on slippers, if I happen to have a pair of slippers with me, keeping them on until I have nearly reached my destination; but that my feet are quite clean and my toenails have a nice bright, dark red polish on them.