Speaker phone calls
How about a bit of train etiquette? Not much to ask in my view. If you are on a train, wear headphones. Be it YouTube or a Teams call. No-one else needs to hear it. They aren't even expensive, a few quid off Amazon (moral issues with rampant consumerism aside). While we are on the subject, just having a conversation moderately loudly, that's roughly the same. When I am prime minister I'm making all trains quiet coaches.