In Sweden there's usually a quiet area on trains and you can book a "quiet seat" in advance as well which I did last weekend because I wanted to study. I only had time to enjoy the peace and quiet for five minutes. A girl who was talking on her mobile took a seat near me. I thought that she would finish her call as the train pulled out, but she didn't. People around me exchanged looks and started to move about. No one said anything.
In the end the people around me annoyed me more than the girl on the phone. It was so frustrating that they kept quiet even though it was clear they got disturbed. I took a deep breath and asked the girl if she knew that she was in the quiet area. She didn't and finished her call. The other passengers didn't show any appreciation of me. Back to silence.
Usually I'm also one of the passive people on trains, so I'm very proud that I said something. I wouldn't say it's just Swedish people keeping their mouth shut instead of acting. It would probably happen in the UK too, or what do you think?