Human error may have played a role in this week's collision between two trains at Peelton near King Williams in which two people were killed.
They were Prasa employees, Piet Baloyi and Yingwani Shivambu.
Several other people were seriously injured, including a train driver and an assistant who jumped off the train just before the crash.
The Rail Safety Regulator says the preliminary report into the accident will be finalised on Friday.
Spokesperson, Babalwa Mpendu, says their inspectors completed their preliminary investigation of the crash site.
"What we can tell is that we know for sure that both trains were given authority on the line which is a single line and therefore it should not have happened. This should never have happened and resulted in the accident" she said
