The Railway Police identified the victim as Sapna Shukla, resident of suburban Ghatkopar.
The incident took place at the platform number 1 of Kurla station Tuesday evening.
The accused Subhashish Malik (19), in a bid to snatch her chain from behind, pushed her onto the tracks and she was run over by the train, they said. She was declared dead at the hospital.
People on the platform and Railway Protection Force personnel chased down the accused. He was booked under section 304 of IPC (culpable homicide not amounting to murder).
The incident was captured on CCTV cameras.
According to a report in Mid-Day, the victim was working for HDFC Life Insurance Company and had settled in Mumbai from Lucknow one and a half years ago. The accused, on the other hand, originally belonged to Orissa and wanted to earn lots of money before returning to his hometown.