Robert Buckland, 18, of no fixed address, was convicted last January of the attempted murder of Alison Kennedy, 28.
Ms Kennedy, a charity worker from Northern Ireland, was travelling in a deserted carriage to see her sister in Surrey in March last year when Buckland attacked her from behind, embedding a Bowie-style hunting knife deep into her skull.
Judge Geoffrey Grigson said at the Old Bailey in London yesterday today that doctors were satisfied Buckland was suffering from mental illness and the condition was susceptible to treatment. He would therefore make an interim order that the 18-year-old should be examined at Broadmoor for a minimum of 12 weeks, before being sentenced.
But he added: "Even with a defendant as young as you, given the horrific nature of the crime, my prime duty is to protect the public."
Buckland had fantasized about knifing a woman in the head while still at school the court had been told. When he spotted Ms Kennedy sitting alone in a carriage, he had found his real-life victim. She is still suffering physical and psychological effects from the attack.
Judge Grigson told Buckland: "You should understand whatever conclusion the doctors come to, it is for the court to decide at the end of the day, whether such an order is a suitable means of dealing with you."
He had heard from Dr David Mawson, consultant psychiatrist at Broadmoor, that there was "much to be learned about the defendant - many important background details need to be researched ... We do not know yet the purpose, the motive behind the attack and the nature of the risk he poses to others."
Buckland had intended to kill Ms Kennedy. When she turned and rose from her seat, holding the knife in her head, he ran away scared and tried to jump from the train, the court had been told during his trial. Ms Kennedy was left to stagger along the train for help with the five-inch blade still in her skull.
Although she will never fully recover, Ms Kennedy now hopes she can get on with her life. Immediately after Buckland's trial, she said she felt "a great sense of relief at the result and a great sense of satisfaction to be here to see it for myself". She said she thought she was going to die in the attack.
She had worked in London as an arts festival co-ordinator after obtaining a degree in arts and design and completing a post-graduate course in sculpture. She returned to work for the Multiple Sclerosis Society in Northern Ireland as an education officer last year and was described as "a dedicated and forward planning young person".
Buckland had left home at 16 after trouble with his stepmother but by March last year he was fed up with sleeping rough. He was on his way to Guildford to seek a bed for the night when he spotted Ms Kennedy. He had admitted wounding her with intent to cause grievous bodily harm, but denied attempted murder.Reuse content