Transit Crime Investigation Unit detectives have charged a man following an alleged affray on a train near Parliament Railway Station yesterday.
Emergency services were called to reports of an altercation on the Frankston line train shortly after midnight.
A 20-year-old man was located on the platform of Parliament Railway Station with life-threatening injuries and transported to hospital.
Police quickly responded, arresting a 26-year-old man in Hardwood Place.
The Cranbourne West man, who is not believed to be known to the victim, has been charged with intentionally cause serious injury and affray.
He was remanded to appear at Melbourne Magistrates' Court today.
Detectives believe there were several people in the train carriage and on the platform at the time who are yet to speak with police and are urging them to come forward.
Anyone who witnessed the incident, has footage or any information is urged to contact Crime Stoppers on 1800 333 000 or submit an online confidential report at www.crimestoppersvic.com.au.