Transport Minister Blade Nzimande wants an urgent report on the Kempton Park train crash after 320 people were injured in the collision between two trains on Thursday.

Nzimande is seeking answers from the Rail Safety Regulator (RSR), his spokesperson Ishmael Mnisi said on Friday.

"Minister Nzimande further directed the Passenger Rail Agency of South Africa (PRASA) to prefer severe consequence measures in the event that the RSR report attributes the collision to human error," Mnisi said.

The trains were en route from Johannesburg's Park Station to Pretoria and, according to Metrorail spokesperson Lillian Mofokeng, were carrying around 4 000 commuters between them when the crash occurred at Van Riebeeck Park station.

Mofokeng said that of the 320 people injured in the crash, three commuters were taken to hospital with injuries regarded as serious, but not critical.

Initial reports indicate that the first train was stationary at Van Riebeeck Park Station due to technical problems when it was rear-ended by the second train.

She said Metrorail was trying to understand how the second train driver was allowed into a section where the existence of a stationary train had been reported to the depot.

They were using the controversial manual authorisation system at the time. Metrorail has said previously it is forced to use this method because of severe cable theft and infrastructure damage that has crippled electronic communication to the signalling network.

The method involves train drivers getting permission in writing or over the phone to pass robots on the line.

Mofokeng said the line was cleared on Thursday night and was fully operational for Friday morning's commute.

The investigation into what led to the crash will continue.

"We do not rule out the possibility of human error," said Mofokeng, adding that action will be taken if that was the case.

Nzimande also wants a Railway Asset Condition Assessment Report to assess the state of the network and wants PRASA to fill vacant safety positions to ensure there is tight supervision of train controllers.

This comes as calls mount for Nzimande to declare a state of emergency regarding mounting rail transport problems, which have included a series of train fires suspected to be arson in the Western Cape and in KwaZulu-Natal.

RSR spokesperson Madelein Williams told News24 the special directive includes instructions on manual authorisation and directs that the vacant positions regarding supervising these authorisations be filled.

"This is something we are definitely going to scrutinise," she said of the Kempton Park crash.