I tend to remove my shoes during long train journeys, for the sake of comfort. That is not something that many people do here in the UK. I expect some people would regard it as anti-social.
I was pleased to find on the way back from London today, that I was sat next to a young man who had removed his shoes.
Interestingly, although he was wearing sneakers without socks, I could not smell anything offensive. I think people do exagerrate how much feet tend to smell.