A man accused of throwing stones at 10 people on a train has been linked to three other knife incidents, police said.
Anthony Williams, 32, of the homeless shelter, was charged with 10 attempted murders in Doncaster, Cuncastershire on Saturday.
The British Transport Police (BTP), which is leading the inquiry, said it was linked to the launch of a 14-year-old boy in Peterborough on Friday night.
Two incidents in which a man entered a barber shop in the city – even at one time holding a knife – were also linked.
BTP also explained that the attacks were also linked to the rail service, which made an emergency stop at Huntingdon, with the fourth incident on a DLR train on Saturday.
Mr Williams has been charged with an 11th count of attempted murder in the incident, after a 17-year-old man was stabbed on a train in East London.
Dep Ch Con Stuart Ciundy said the BTP was increasingly seen by police across the rail network to “reassure” staff and the “travelling public”.
The BTP said that a 14-year-old boy was reportedly stabbed by a man in Henry Penn while walking in the City Center and was taken to the hospital at around 19:10 GMT on Friday.
Cambridgeshire police said the offender had left the scene at the time of the call and despite searches, the offender has not been identified.
The same evening, at around 19:25, the police said that a man with a knife entered a barbershop in Fletton in the town. The incident was reported two hours ago.
The person is no longer at the scene so the force did not send officers, said BTP.
The next day, around 09:25 on Saturday, the same barbers ‘reported a person who entered the shop while he was still on the scene.
Officers arrived within 18 minutes but he left the scene.