A helicopter airlifted the driver to a nearby hospital at 9am on Thursday morning, said emergency services spokesperson Johan Pieterse. He was trapped inside the train after the crash.
"Many are walking wounded and already left. There are 20 people in serious condition and one, the driver of the second train, is in a critical condition," Pieterse said.
He said 20 people were seriously injured in the crash at about 7am, and that 150 people were still able to walk, although injured.
Police at the scene said one of the trains was stopped on the railway line between Cor Delfos and Saulsville when it was hit from behind by another.
Among other things damaged were the powerlines on top of the trains.
Earlier, Pieterse said the railway line between Cor Delfos and Saulsville had been completely closed because of the accident. Train services had been interrupted as a result of the accident, whose cause was being investigated, he added.
South Africa signed a $5.8-billion contract with France's Alstom in December to supply 3 600 new train cars as part of a 10-year programme to overhaul its ageing rail network. – Sapa, Reuters