A 35-year-old man has been charged with murdering father-of-one Lee Pomeroy on a train from Guildford to London.
Darren Shane Pencille, of Willbury Road, Farnham, was charged after detectives were granted extra time to question him following his arrest.
He was also charged with possession of an offensive weapon.
He has been remanded in custody and will appear at Staines Magistrates' Court on Monday.
Chelsea Mitchell, 27, of Willbury Road, Farnham, has also been charged with assisting an offender.
She has been remanded in custody and will appear at Staines Magistrates' Court On Monday as well.
Mr Pomeroy had been taking his only son, 14, to London for a day-trip ahead of his 52nd birthday, when he was stabbed to death on the 12.58pm service from Guildford to Waterloo on Friday.
Police were called at 1.15pm to Horsley station and paramedics battled to save Mr Pomeroy, but he was pronounced dead at the scene.
Following Mr Pomeroy's death, a number of British Transport Police officers remained in the Clandon area into the evening.
Mr Pomeroy has been describd as a "devoted family man".
In a statement, his family said: "He was an honest, bright person, who loved music very much, he knew history and art and he was a bachelor of science in Maths.
"He was devoted family man and did everything for his family. He was an honourable man and would always help somebody who was in trouble. He was a loving husband and father, he will be deeply missed by all his family.”
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