Darren Pencille, a 35-year-old man from Farnham, has been charged with the murder of Lee Pomeroy, the 51-year-old who was stabbed on a Surrey train on Friday afternoon.
A British Transport Police (BTP) statement said Mr Pencille had also been charged with possession of an offensive weapon following the attack onboard a London-bound train from Guildford.
Mr Pomeroy, who lived in Guildford and owned an IT firm, was travelling with his 14-year-old son when he was stabbed.
Chelsea Mitchell, 27, was also charged on Sunday with assisting an offender.
“A man has today been charged with the murder of Lee Pomeroy, 51, following an investigation at Horsley station, Surrey,” said a BTP spokesperson.
“Darren Shane Pencille, 35, of Willbury Road, Farnham, has been charged with murder and possession of an offensive weapon in connection to a fatal incident on board a train from Guildford to London on 4 January.
“He has been remanded in custody and will appear at Staines Magistrates’ Court tomorrow.” Ms Mitchell will also appear at the Staines court on Monday.
A police manhunt led officers to a flat in Willbury Road on Saturday morning where they made two arrests.
The 51-year-old victim, who would have celebrated his birthday on 5 January, was described by his family as “an honourable man and would always help somebody who was in trouble”.
“He was a devoted family man and did everything for his family,” it said. They also asked for privacy as they attempted to come to terms with their loss.
Mr Pomeroy and his son boarded the 12.58pm train service between Guildford and London Waterloo at London Road station on Friday.
Police believe a brief row broke out, leading to Mr Pomeroy’s death. The suspect got off at Clandon station following the stabbing, but the train continued on to Horsley station where emergency services attended.
Assistant Chief Constable Sean O’Callaghan, of BTP, said no-one else was being sought in connection with the killing following the arrests.