The incident reportedly took place aboard line G2610 shortly after the train departed from Taiyuan, in northern China’s Shanxi Province on 14th September, at around 4:33pm.
It reportedly began after the elderly couple, identified as Ms Tian and Mr Zhang, took the young woman’s seat and then assaulted her after she made them move.
After the young woman, named as Ms Li, boarded the train, she allegedly found that the elderly man was sitting in her seat and he asked her to take his instead.
However, the 23-year-old refused and asked to have her assigned seat back.
The man apparently moved but Li claims the two then began hurling insults at her and kicking her seat.
She turned around to ask them to stop but they continued verbally abusing her.
Soon, the argument escalated into a physical altercation.
Phone footage shows the two women in a fierce brawl as Li tries to defend herself from the elderly woman, who can be seen physically attacking her and shouting at her.
Her husband pushes Li off and attempts to restrain her as the wife continues yelling and smacking her on the head.
Another piece of footage shows the woman grabbing Li by the hair when a female passenger walks by and seemingly tries to break up the fight.
The trio continues brawling until a man arrives and intervenes.
But the two keep yelling at each other as he moves away as the footage ends.
Photos shared by Li show several scratches on her arm, neck and chin apparently caused during the fight.
She told local media: “Her seat was behind mine, and she was violently shaking it.
“This happened at least three to four times from the moment I boarded until the incident occurred.
“At that time, I was resting, so I turned around to ask her if she could stop.
“She began insulting me and then struck my left arm.
“After being hit, I prepared to use my phone to gather evidence, but she knocked my phone out of my hand, then restrained both of my arms and scratched and slapped me.
“The man accompanying her also assaulted me.”
Both parties sustained varying degrees of injuries from the scuffle, local media reported.
After the train arrived at its destination at 6:20pm on the same day, the police arrived on the scene and began investigating.
Li added: “Right now, I don’t know where the individuals who assaulted me are, and I don’t have their contact information.
“My current demand is that I hope the police can quickly identify the assailants, as their behaviour was quite severe.”