More than 300 people were injured when two trains collided at Van Riebeeck Park Station near Kempton Park in Gauteng.
Metrorail said 32 of the 320 commuters who were injured, suffered serious injuries but were not critical.
The state-owned company said a board of inquiry would be appointed to investigate the crash which happened when a train rear-ended a stationary train which was experiencing problems.
The Rail Safety Regulator has already dispatched a team to begin the probe into Thursday night's accident.