Yesterday (09.07.2020) in the 6:02 train Bern-Zürich one person refused to wear a mask. This person got in the train in Olten. She sat in front of me, in a row of individual seats in a 2nd class coach, not keeping the 1.5 m distance. I asked her politely to wear a mask. She just replied 'no'. I asked her to find another seat where she could keep the 1.5 m distance with other passenger. She replied 'no' again. I found a SBB staff and told her the situation. She came and asked this passenger why she was not wearing a mask. She replied that she forgot to get one mask. The SBB staff reminder where to buy a mask at the station, but she did not take further actions. She said that she can do nothing, because she is not the Police. Another passenger kindly gave her a mask, that she accepted to wear. After the SBB staff left, the passenger sitting in front of me asked me whether I was Swiss started and started insulting me. I did not reply to her verbal aggression, but I felt very intimidated. I do not know what is the point of asking passengers to wear a mask if there is no consequences if they do not do it, and they can become aggressive with other passengers if they are asked to do it. I am astonished by the passivity of the SBB staff in this regards.