A man killed on a train in front of his teenage son was stabbed nine times, a court has heard.
Lee Pomeroy, 51, from Guildford, died in the attack on a train near the town on Friday.
Darren Pencille, 35, of no fixed abode, appeared at Staines Magistrates' Court charged with murder and possessing an offensive weapon.
Addressing the court, Mr Pencille said: "Innocent until proven guilty," adding: "I'm paranoid. I'm hearing voices."
Mr Pencille was remanded in custody to appear at Guildford Crown Court later on Monday.
Chelsea Mitchell, 27, from Willbury Road in Farnham, who is accused of assisting an offender, has also appeared in court.
She is accused of helping Mr Pencille leave the scene and change his appearance.
Ms Mitchell was also remanded in custody until the crown court hearing.
Magistrates were told Mr Pomeroy, an IT consultant, suffered nine stab wounds in the attack in front of his 14-year-old son.
Mr Pomeroy, who would have celebrated his 52nd birthday on Saturday, 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," they said.
Mr Pomeroy died on the 12:58 GMT train service between Guildford and London Waterloo which he and his son boarded at London Road station on Friday afternoon.