The victim has fractured on of her legs and head.
The Mumbai Police said the girl had boarded the Kalyan-bound train at the Chhatrapati Shivaji Maharaj Terminus (CSMT) on Sunday morning.
The survivor told the police that she jumped off the train after she failed to pull the chains to prevent advances of her perpetrators.
The victim told the media, “The ladies compartment was empty and a man in pink shirt had boarded the train. On asking him to deboard, he started molesting me.”
“I was shocked and in state of fear. The train had crossed CSMT and on seeing railway workers I decided to jump,” added the victim.
The girl was rushed to a city-based hospital by Government Railway Police.
According to doctors the girl has suffered a fracture on her heel and received 20 stitches.
An FIR has been registered against an unidentified person.