A 57-year-old lawyer was arrested for allegedly sexually assaulting a minor girl on the Thiruvananthapuram-Chennai Express, police said.
The advocate allegedly assaulted her when she was asleep.
The girl woke up and raised an alarm, following which her family nabbed him and informed the Travelling Ticket Examiner.
The Chennai-based lawyer had boarded the train from Coimbatore on April 21 night, police said.
He was handed over to railway police here, which registered a case against him under The Protection of Children from Sexual Offences Act (POCSO Act), 2012.
The lawyer was later lodged in a prison in Coimbatore.