People here don't know the meaning of the word overcrowded!
When riding a crowded train abroad, you want to say something like "It's not nearly as crowded as trains in Japan". One of the above suggested sentences may fit your situation.
海外で混みあった電車に乗ったときに、"It's not nearly as crowded as trains in Japan"（日本の電車ほど混んでいないよ。）と言うことができます。
この場合、例のフレーズを使うといいでしょう。
This train isn't nearly as bad as the crowded trains in Japan.
This train is not as crowded as the trains in Japan.
This train is really good compared to how crowded the trains are in Japan.
This train isn't nearly as bad as the crowded trains in Japan.
This train is not as crowded as the trains in Japan.
This train is really good compared to how crowded the trains are in Japan.
This train's not as crowded as the ones in Japan.
If you think this train is crowded, you should see the ones in Japan.
This isn't nearly as crowded as the ones in Japan.
You should see the trains in Japan if you want to see what crowded really looks like.
You wouldn't believe how crowded the trains in Japan are compared to this one.
This train isn't nearly as bad as the crowded trains in Japan.（日本の電車と比べたら大して込んでないよ）
This train is not as crowded as the trains in Japan.（この電車は日本の電車ほどは混んでないよ）
This train is really good compared to how crowded the trains are in Japan.（日本の電車の混み具合に比べたらこれはいい方だよ）
This train's not as crowded as the ones in Japan.（この電車は日本の電車ほどは混んでないよ）
If you think this train is crowded, you should see the ones in Japan.（この電車が混んでいると思うなら、日本の電車を見た方がいいよ）
This isn't nearly as crowded as the ones in Japan.（日本の電車と比べたら大して込んでないよ）
You should see the trains in Japan if you want to see what crowded really looks like.（"crowded"（込んでいる）がどういう状態なのか日本の電車を見れば分かるよ）
You wouldn't believe how crowded the trains in Japan are compared to this one.（日本の電車はこれよりもはるかに混んでいるから）
1) This is not nearly as crowded as Japanese trains.
「日本の電車に比べたらこんなの全然混んでいないよ。」
not nearly as crowded as で「及ばない・到底...でない」
2) This is nothing compared to the trains in Japan.
「こんなの日本の電車と比べたらなんて事ないよ。」
This is nothing で「大した事でない・なんて事ない」
ご参考になれば幸いです！
"As bad as" is a way to make a comparison by saying that two things are equal."Isn't nearly" means not close to or not comparable to. I hope that this helps. :)
"As bad as"（同じくらい悪い）は、二つのものが等しいことを伝える言い方です。
"Isn't nearly"は「近くない」「比較にならない」という意味です。
お役に立てると幸いです。
When something is busy and full of people it is said to be 'crowded' meaning there are crowds of people
Not nearly means it is not as much as something else
混雑して人でいっぱいになっている状態は、'crowded' で表せます。これは「'crowds of people'（大勢の人）がいる」という意味です。
'not nearly' は「～ほどではない」という意味です。
It's no where near as crowded as in Japan. - "No where near" means it is very different. "Crowded" means a lot of stuff of people in one area. "Tokyo city is very crowded".
Japan is way more crowded than this. - "way more"means more by a lot, not just a little.
This doesn't even compare to Japan. - "doesn't even compare" it is so different that you cannot compare them.
It's no where near as crowded as in Japan.（日本の混みように比べたら大したことない）
→"No where near" は「全然違う」という意味です。"Crowded" は、一つの場所にたくさんの人または物が集まっている状態をいいます。
"Tokyo city is very crowded".（東京はすごく混み合っている）
Japan is way more crowded than this.（日本はこれよりもはるかに混んでいる）
→"way more" は「はるかに／ずっと」という意味です。
This doesn't even compare to Japan.（日本はこれとは比べものにならない）
→"doesn't even compare" は「違いすぎて比べることができない」という意味です。
In comparison with the trains in Japan this train is completely different
This train is jam-packed but the trains in Japan especially Tokyo are beyond comparison
We say "in comparison" when we want to compare something to something else. We are highlighting the similarity between the number of people on trains in Japan and wherever we are at this moment
"Jam-packed" is a way of saying "completely full" to the point that nothing or nobody else can fit. It is very informal and it has British origins. We can definitely use this expression to explain how full the trains are in Tokyo during rush hour.
"in comparison" は、あるものを比べたいときに使うフレーズです。日本の電車に乗る人の数と、別の場所の電車とを比較しているということです。
"Jam-packed" は、もう他に誰も乗れないような満員であることを表す言葉です。とてもカジュアルで、イギリスを起源とした言葉です。ラッシュ時間の東京の電車のことを伝えるのにぴったりです。
英会話講師のKOGACHIです(^o^)/
おっしゃられている内容は、
This is not nearly as crowded as Japanese trains.
「これは日本の電車に近いレベルの混み具合までいってない」
のように表現できます。
以上ですm(_)m
少しでも参考になれば幸いです(#^^#)
お困りの時は、いつでも気軽にご質問ください(^0^)/
★★どうぞよろしくお願いもうしあげます★★
see you soon♪
イギリス 
アメリカ合衆国 
日本 
アイルランド 
