Translation:It's noisy inside the train.
2020.4.29 〜には is the same as 〜に except with the は it puts more emphasis on 〜。
The general structure for using うるさい is
〜が＼は うるさい so
電車の中は うるさい。 is the preferred way to say it. However,
電車の中に おじさんが うるさい。 The old man in the train is noisy.
電車の中には おじさんが The old man In The Train is noisy. (I would hesitate to use all caps IN THE TRAIN here. Maybe an underline?)
Hope this helps.
"There is" shows existence, while "it is" defines or tells what the thing is being. I know I didn't explain that well, so I'll show a few examples:
"There is a bug" would mean that a bug exists anywhere in the world, but most likely near the speaker, otherwise they would not have said it.
"It is a bug" would mean that whatever you were previously talking or looking at, is a bug.
If you were to say "there is noisy on the train", that would be incorrect, as an adjective cannot "exist" in the same way that nouns can, so only "there is noise on the train" makes sense, and might not imply quite as much that's it's too loud, and it would be a different sentence in the Japanese translation.
As I noted elsewhere, it's more like the person is saying "(You're) noisy (and that's bad)!" but the translators did more than just translate: they localized the phrase. So, its meaning was still held with "Shut up!" when used in that way, but it's not really the meaning of the word itself.