The calculated distance (air line) between Randfontein and Ga-Rankuwa is approximately 43 miles respectively 70 kilometers.
By car or train, the actual journey to Ga-Rankuwa is certainly longer, as only the direct route (as the crow flies) between Randfontein and Ga-Rankuwa has been calculated here.
Air line (approximately)
70 kilometers
38 nautical miles