Daily Expression
Ａ:	どうしたんですか。ずいぶんお疲れのようですね。
Ｂ:	今朝もすし詰めの電車だったんだ。もう本当に疲れたよ。
Romaji:
Ａ:	Dooshitandesuka.　Zuibun otsukare no yoodesune.
Ｂ:	Kesa mo sushizume no densha dattanda.　Moo hontoo ni tsukareta yo.
Translation:
Ａ:	What’s the matter with you?　You look so tired.
Ｂ:	The train was very crowded again this morning and I am tired of it.

すし詰め ／ Sushizume:
Originally it means "a pack of Sushi”, as that take-away-style or Sushi in a square box. This expression shows a situation that many people/things are squeezed into a small place as there is no space any more.
Another example
ペーター:	今日初めてすし詰めのバスを経験しました。
鈴木:	そうですか。スイスではそんなに込まないんでしょうね。
Romaji:
Peetaa:	Kyoo hajimete sushizume no basu o keeken shimashita.
Suzuki:	Soo desuka. Suisu dewa son’nani komanaindeshoone.
Translation:
Peter:	Today I experienced a very crowded bus for the first time.
Suzuki:	Did you? I guess buses are not so crowded in Switzerland.
A similar English expression is “packed like sardines”.