The Railway Safety Regulator (RSR) will release preliminary findings into the Kroonstad train accident on Monday, Times Live reported.
At least 19 people died when a Shosholoza Meyl train collided with a truck at a level crossing in the Free State town on Thursday.
The truck driver, who was allegedly drunk, is said to not have stopped at the level crossing as the train was approaching.
Following the accident, investigators were dispatched to the scene.
Spokeswoman for the Railway Safety Regulator, Madelein Williams told the publication that they were in the process of instituting a board of inquiry to establish the root cause of the occurrence and to provide recommendations in order to prevent similar occurrences.
"Preliminary findings into the collision will be released by the RSR on Monday‚ 8 January 2018‚" she said.