I am not really into this whole yuri angle; or rather its cute, but not the reason I really like this manga.
It gives me those vibes of nostalgia to the time I was regularly commuting to uni (I moved closer later) and where you have weird bonds to those people commuting with you.
Like, you never talk to them, except when the train is delayed or there are some other emergencies. Neither of you want to talk either, cause you just want to get home or to your job/school and just want to relax, sleep or read along the way. And if someone were to talk to you, you might have to chat with them every day. But you acknowledge them and greet them usually with a nod and a smile if your eyes meet. And if the train/bus is overcrowded, you'd rather sit with them, cause you know they are cool and when they have to get off.
Still, if they are not there the next semester or if you commute at a different time, you kinda miss them.