Initial investigations by the Railway Safety Regulator into the Pretoria passenger train crash showed that a communication breakdown between officials was the cause of the crash.

Three people were killed and over 600 others injured when two trains travelling on the same line collided on Tuesday.

One train entered the section between Pretoria North and Mountainview station wrongfully, after the officer and driver failed to comply with language policy when authorising entrance.

The section between Mabopane and Pretoria has been closed until further notice.

Metrorail announced on Wednesday that 18 buses were assigned to accommodate affected commuters.