A 112 people were injured after two Metrorail trains collided this morning in Selby, Johannesburg.

Thembisa Lukee, 42, who owns a creche right next to the railway tracks said she heard a loud bang at around 7am.

"People were screaming and crying. It was a big shock for all of us," she said.

Lukee said she rushed to assist the injured and gave them sugar water for their shock.

"There were school kids and old people lying on the ground. Because this place is hidden I helped the ambulances to come in to take the injured to hospital," she said.

Prasa spokesperson Lillian Mofokeng confirmed the trains' head-on collision. Mofokeng said one train was travelling from Faraday station towards New Canada while the other was from Naledi, Soweto.

"A total 112 commuters, mostly without valid train tickets, sustained minor injuries, and seven with serious but not critical injuries are receiving medical attention at four local various hospitals," Mofokeng said.

She said at this stage the cause of the accident was still unknown but was being investigated.

"A board of enquiry will be instituted to determine the root cause of the accident and Prasa will be closely working with the Railway Safety Regulator."

The Metrorail team is currently on the scene investigating and clearing up the tracks.