On Tuesday (September 9), two 16-year-olds were on a Thameslink train between Streatham and Tulse Hill.
The teenagers were approached by two older men who demanded their phones and items of clothing.
The teenagers refused and were physically attached and punched by the two men.
The two men also allegedly threatened to kill them.
The British Transport Police is appealing for witnesses to come forward if they saw the incident or have any information.
Anyone who can help should contact the British Transport Police by texting 61016 or by calling 0800405040, quoting reference 697 of 9 September.
Anyone who wishes to report anonymously can contact Crimestoppers on 0800 555 111.
A spokesperson for the British Transport Police said: “Officers are appealing for witnesses after two teenagers were threatened and attacked on a train to Tulse Hill.
“At around 9.40pm on Tuesday 9 September, two 16-year olds were on a Thameslink train between Streatham and Tulse Hill.
“They were approached by two older men, who demanded their phones and items of clothing.
“When the teenagers refused, they were physically attacked and punched by the two men who also threatened to kill them.
“If you witnessed this incident or have any information, contact BTP by texting 61016 or by calling 0800 40 50 40, quoting reference 697 of 9 September.
“You can also contact Crimestoppers anonymously on 0800 555 111.”
