The incident took place as an unidentified man boarded the ladies compartment on Sunday evening between Marine Lines and Charni Road stations of Western Railway and tried to snatch the bag of Michelle Mark, a United States national, police said.
According to news reports, the young man attacked her with a blade and slashed her face, neck and arms and fled after snatching her iPhone.
Other passengers in the compartment took the woman to authorities at Mumbai Central station.
Meanwhile, a senior officer of Government Railway Police alleged that Railway Protection Force (RPF) constable as well as the station master refused to help the woman, who had received minor injuries on hand and face, and asked her to go to GRP office instead.
Under the law, both RPF personnel as well as station master are responsible for offering medical help, the GRP official said, adding that he would be reporting the matter to higher authorities.
A case has been registered against the unidentified man and the woman was discharged from hospital after treatment.
The attacker was suspected to be a drug addict, police said adding, CCTV footage will be checked to ascertain his identity.
On July 26 this year, another woman was attacked inside the ladies compartment near Mahalaxmi station when she resisted a molestation attempt by a man.
With PTI inputs.