Hang on tight to mommy's hand, so you don't get hit by the train.
Don't let go of mommy's hand. You don't want to fall and get run over by a train.
この場合、次のような言い方ができますよ。
ーHang on tight to mommy's hand, so you don't get hit by the train.
「電車し轢かれないようママの手をしっかりつないでね」
to get hit by the train で「電車に轢かれる」
ーDon't let go of mommy's hand. You don't want to fall and get run over by a train.
「ママの手を離さないでね。転んで電車に轢かれたくないでしょ」
to get run over by a train で「電車に轢かれる」とも言えます。
ご参考まで！
カナダ 
