This is the shocking moment a woman was caught on video threatening to stab commuters and using the N-word as she hurled abuse at fellow passengers.
The worrying video shows a young woman dressed in a lilac outfit calling a man a "f***ing Algerian c***" - before telling him she'll attack him.
Leaning over the seats she tells the unseen man she will spit on him and added: "You see me - I will cut your head off [...] I will stab you in the f***ing face".
Fellow worried passengers continue to record the explosive argument which happened on the over-ground service from Basildon in Essex to West Ham.
She can be seen launching herself at one commuter - who can be seen pushing back.
She turns on passengers, including the man who filmed the attack and she was involved in the pushing incident with, calling him a "bitch arse n***er".
But then disputes she's racist - because she is "from Kenya".
She alleges in the clip she started arguing with the first man because he "raised his hands" at her pal - but there is no evidence of this in the footage.
A police investigation has been launched into the incident which happened on Friday night.
One of the passengers, a 30-year-old a software engineer from London, said: "It was very difficult.
"I was trying not to have any physical contact with her, but I wanted to protect myself, and she was being violent towards someone else.
"I'm black and I'm a guy, so I know I have to tread that very fine line very carefully.
"No one wants that kind of ambiguity.
"At the time I wasn't paying attention to the fact that she was threatening my life.
"I wasn't thinking about my safety at that point I just wanted her to stop picking on the guy.
"I was cross about her behaviour and that the situation had escalated.
"It felt real but I ignored it because I didn't feel terrified of her and I'm still not.
"The more she said it, I wondered if she has experience of stabbing people, or being involved in things like that, so I knew then I had to report it.
"Whatever is going on, a dialogue is better than that physical and racial abuse.
"It was very concerning: when she realised we were filming she kept saying he had done stuff to her, but I don't think he had anything to do with her - she was just making it up to try and cover herself.
"I hope people take from this just to be nice to each other.
"We all come from different places but we are basically the same.
"It felt like a betrayal that she said she's half Kenyan.
"In that case she should know better."
The man said the woman in lilac, and her pal, made unkind remarks to someone else at the station as they got on the train at the same time as him and three of his relatives.
he said there was some discussion between the women and the man she is seen picking on at the start of the footage.
In the clip, she can be seen moving towards him, and he can be seen putting his hand up and asking her to step back.
She can be heard calling him a "dirt n***er" and can be seen calling a friend and asking them to bring "rams" - slang for knives.
The British Transport Police said officers are investigating the incident and have asked anyone with information to contact them.
A spokesperson said: 'British Transport Police received a report of a racially aggravated public order offence on-board a train near West Ham Underground station at 11.31pm on Friday 16 July."