I witnessed a funny exchange in the train recently. We were not in a "silence" carriage, but for whatever reason, nobody was talking, except this one guy who was talking to someone on the phone about cars, among other things. Out of nowhere, an elderly lady cussed him out for his "dirty talk about cars" and his orange jacket. He told her quite bluntly to mind her own business because they weren't in a silence carriage, so he could talk all he wanted. She shut up, he continued talking, but a bit quieter this time. Everybody was happy.

Mostly people tend to be fairly quiet and ignore other people while traveling, unless they already have a conversation partner.

Yes this! Just try talking in a "silent carriage" on the train. That said, on a non-silent carriage, unless the talk is offensive, people tend to live and let live in my experience.