I too have been politely requested to delete a photograph which accidentally contained the image of a passerby. It wasn't in a rail context, I was taking a typical tourist shot in Luzern. After that I checked up and discovered the following in the Switzerland entry on Wikimedia Commons's guidance on personality rights in photographs:
Taking a picture of a person in a public space: Requires consent (see explanation below)
Publishing pictures of a person in a public space: Requires consent (as per above)
Commercial use of a published picture of a person in a public space: Requires consent (as per above)
Swiss civil law contains a general clause for protection of personality rights, which may be restricted only with the consent of the person affected. This applies to the right to the own image, even if a picture is taken in a public space. In principle, any unauthorized picture which aims to depict the person as such is considered an infringement of personality rights (according to the jurisprudence of the Swiss Federal Court). Therefore, just taking a person's photograph is an offensive act and consent must be obtained from any person recognizably depicted as an individual, unless their appearance is merely accidental and has nothing to do with the purpose of the image. Consent can be given expressly (either written or verbal) or implied through actions. It is generally recognized by case law and legal doctrine that consent is implied for pictures of public figures, at least when performing their public functions or activities (not necessarily also in private situations). Consent is also implied for people consciously and voluntarily exposed to the public in some kind of public event. As an exception, predominant and mostly public interests (e. g. public information, science) will allow an unauthorized picture to be admitted.
The Swiss personality right to privacy does not protect financial interests. Therefore it makes no difference in terms of the right to one's own image if a picture is used commercially or in a non-profitable way.