According to reports, the incident happened after the accused, who is said to have been drunk, entered the ladies compartment and started molesting the woman.
The woman had boarded the train at Churchgate while the accused got into the compartment at Mahalaxmi and allegedly started molesting her. According to reports, the woman was the only passenger in the compartment.
The victim, who works as a nurse in a city hospital, raised an alarm as soon as the train reached Lower Parel.
The man tried to escape, but the other passengers in the train caught hold of him and handed the accused over to the police.