Two final points worth noting:
1: The train company initially refused to recognise the what he said was even sexist.
2: Her response (from which I think we can infer that she has the same 'real problems as the rest of us):
"I found it offensive for several reasons. I didn't hear the man's remark, my boyfriend told me what had happened after we got off the train So it kind of felt like a joke about me, more than a joke meant as a way to laugh with me. Also, it's obviously a sexist joke and I really can't see what's funny about sexism.
And finally, I think that it really bothered me because it's not an isolated event, it's really part of a continuum of violence against women. I feel like it was part of a normalised sexism that people don't take seriously, although it actively contributes to reinforcing gender stereotypes.
My boyfriend told me their argument wasn't valid because he got the same problem as me with opening the doors on other occasions in the presence of a staff member, and they would always say something along the lines of 'oh yeah these buttons are a bit difficult'
I'm fully aware that this is not the worst episode of sexism that someone could think of, but unlike what many comments suggested on my post, I think it's still legitimate to denounce this type of behaviour/jokes while also fighting for the bigger picture".