Three people, believed to be security guards, were seriously injured after being thrown off a train at the Cleveland station in Johannesburg on Thursday.
Emergency services spokesperson Malcolm Midgley said one was critically injured and the other two seriously when they were flung off the train at about noon.
He said people on the scene linked the incident to the security-guard strike, saying the victims were apparently guards not taking part in the industrial action.
This was the third or fourth such incident in the Cleveland area this week.
On the West Rand, two security guards were seriously assaulted on Wednesday evening in another incident that appeared to be related to the strike.
West Rand police spokesperson Captain Joseph Mogoai said the pair were accosted by a gang of 10 people — thought to be striking security guards — on a train between Witpoortjie and Roodepoort.
They were attacked and beaten with sjamboks. Both were in a stable condition in a nearby hospital on Thursday morning.
No arrests have been made since the incident.
Several security guards not taking part in industrial action have been attacked by strikers in the past weeks and several have been murdered.
A number of incidents have taken place on trains, with some guards stripped naked before being severely beaten and then hurled off the train.
Several of the victims have died. — Sapa