I was getting off the train and my foot got caught on some guy's backpack strap that he left on the floor of the train. I almost fell over.
この場合、次のような言い方ができますよ。
ーI was getting off the train and my foot got caught on some guy's backpack strap that he left on the floor of the train. I almost fell over.
「電車を降りようとして、電車の床に置いてあったリュックの肩紐につまずいて転けそうになった」
my foot got caught on ... で「…につまずいた」
almost fell over で「転けそうになった」
ご参考まで!