The driver and crew, with signallers, diverted the train to the slow line and halted it at Huntingdon within about 14 minutes of Peterborough departure, enabling swift police access.
There were no fatalities, and 10 people were taken to Addenbrooke's Hospital; nine victims were in life-threatening condition at the time.
Witnesses described passengers fleeing from a man with a large knife, with some seeking refuge in toilets to escape the rampage.