I really can't stand people on the train who can't sit still in their seats, keep shuffling around in their bags, and work on their laptop while their elbows get in their neighbors' way.
ご質問ありがとうございます。
"I really can't stand people on the train who can't sit still in their seats,"＝「電車で、席に静かに座れない人々が耐えられない」
"keep shuffling around in their bags,"＝「バッグの中をごそごそして」
"and work on their laptop while their elbows get in their neighbors' way."＝「そしてラップトップを使用しながら、肘が隣人の迷惑になっている人達を。」
ご参考に。
I hate people who are so busy doing all kinds of things on the train, especially when they are sitting right next to you. They are such a nuisance to everyone.
この場合、次のような言い方ができますよ。
ーI hate people who are so busy doing all kinds of things on the train, especially when they are sitting right next to you. They are such a nuisance to everyone.
「電車で忙しそうにいろんなことしている人が嫌い。特に隣に座ってやられるとすごい嫌だ。みんなの迷惑だよ」
people who are so busy doing all kinds of things on the train を使って「電車でずっとがさがさ何かやっている人」を表現できます。
ご参考まで！
アメリカ合衆国 
カナダ 
